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Workbook

EduKit PA

Project kit

Process automation

With CD-ROM

Festo Didactic

563971 EN

Use for intended purpose

This system and the workbook have been developed and produced exclusively for training and further

education in the field of process automation and technology. The respective training companies and/or

trainers must ensure that all trainees observe the safety precautions which are described in the

accompanying manuals.

Festo Didactic hereby excludes any and all liability for damages suffered by trainees, the training company

and/or any third parties, which occur during use of the system in situations which serve any purpose other

than training and/or vocational education, unless such damages have been caused by Festo Didactic due to

malicious intent or gross negligence.

Order no. 563971

Revision level: 04/2009

Authors: Bernhard Schellmann, Hans Kaufmann

Editors: Jürgen Helmich, Klaus Kronberger

Graphic design: Doris Schwarzenberger

Layout: 05/2009

© Festo Didactic GmbH & Co. KG, 73770 Denkendorf, 2009

Internet: www.festo-didactic.com

e-mail: [email protected]

© Adiro Automatisierungstechnik GmbH, 73734 Esslingen, 2009

Internet: www.adiro.com

E-mail: [email protected]

The reproduction, distribution and utilisation of this document, as well as the communication of its contents

to others without explicit authorisation, is prohibited. Offenders will be held liable for compensation of

damages. All rights reserved, in particular the right to file patent, utility model and registered design

applications.

© Festo Didactic GmbH & Co. KG 3

Table of contents

Introduction _______________________________________________________________________________ 9

Training content _____________________________________________________________________ 5

Learning objectives ___________________________________________________________________ 6

References to German school syllabi and vocations ________________________________________ 6

Obligations of the trainees ____________________________________________________________ 11

Risks associated with the modular production system _____________________________________ 11

Guarantee and liability _______________________________________________________________ 11

Use for intended purpose _____________________________________________________________ 12

Safety precautions __________________________________________________________________ 12

Transport __________________________________________________________________________ 14

Unpacking _________________________________________________________________________ 14

Scope of delivery ____________________________________________________________________ 14

Visual inspection ____________________________________________________________________ 14

Maintenance _______________________________________________________________________ 15

Updates ___________________________________________________________________________ 15

Part A – Plant construction

1. Process description_________________________________________________________________ A-3

2. Planning __________________________________________________________________________ A-9

3. Installation _______________________________________________________________________ A-43

4. Commissioning ___________________________________________________________________ A-47

5. Marketing and sales _______________________________________________________________ A-51

6. Evaluation of learning objectives for plant construction __________________________________ A-55

Part B – Practice-based learning: manual measurement, open-loop and closed-loop control

1. Manual measurement _______________________________________________________________ B-3

2. Manual open-loop control __________________________________________________________ B-13

3. Manual closed-loop control _________________________________________________________ B-37

4. Evaluation of learning objectives for manual measuring, open-loop

and closed-loop control ____________________________________________________________ B-47

Table of contents

4 © Festo Didactic GmbH & Co. KG

Part C – Practice-based learning: automated measurement, open-loop and closed-loop control

1. Basic principles ____________________________________________________________________ C-3

2. Automated measurement ___________________________________________________________ C-13

3. Automated open-loop control _______________________________________________________ C-25

4. Automated closed-loop control ______________________________________________________ C-41

5. Evaluation of learning objectives for automated measurement, open-loop

and closed-loop control ____________________________________________________________ C-59

Part D1 – Plant construction with solutions

1. Process description________________________________________________________________ D1-3

2. Planning _________________________________________________________________________ D1-9

3. Installation ______________________________________________________________________ D1-43

4. Commissioning __________________________________________________________________ D1-47

5. Marketing and sales ______________________________________________________________ D1-51

6. Evaluation of learning objectives for plant construction _________________________________ D1-55

Part D2 – Practice-based learning: manual measurement, open-loop and closed-loop control with solutions

1. Manual measurement ______________________________________________________________ D2-3

2. Manual control __________________________________________________________________ D2-13

3. Manual control __________________________________________________________________ D2-37

4. Evaluation of learning objectives for manual measurement, open-loop

and closed-loop control ___________________________________________________________ D2-47

Part D3 – Practice-based learning: automated measurement, open-loop and closed-loop control with solutions

1. Basic principles ___________________________________________________________________ D3-3

2. Automated measurement __________________________________________________________ D3-13

3. Automated open-loop control ______________________________________________________ D3-25

4. Automated closed-loop control _____________________________________________________ D3-41


and closed-loop control ___________________________________________________________ D3-59


Introduction

Festo Didactic’s process automation and technology learning system is aimed at various educational

backgrounds and vocational requirements. The systems and stations included with the modular production

system for process automation (MPS® PA) facilitate training and vocational education which is based on

real-life company situations. The hardware comprises industrial components specifically prepared for this

purpose.

The process automation project kit provides you with a suitable, practical system with which you can convey

key competencies including:

· Social

· Technical

· Procedural

In addition, teamwork, willingness to cooperate and organisational skills are also part of the training.

The learning modules focus on realistic project phases. These include:

· Planning

· Installation

· Wiring

· Commissioning

· Operation

· Open-loop control technology

· Closed-loop control technology

· Maintenance

· Troubleshooting

Training content

The following subject areas are covered:

· Mechanical

– Mechanical layout of a system

· Process engineering

– Read and prepare flowcharts and documentation

– Piping connections for process engineering components

– System analysis

· Electrical engineering

– Create electrical circuit diagrams

– Correct wiring of electrical components

· Sensor technology

– Correct use of sensors

– Measurement of non-electrical, process engineering and control technology quantities

· Commissioning

– Initial commissioning of a process system

– Initial commissioning of a controlled system

Introduction


· Open-loop control technology

– Controlling actuators

– Relay circuits

· Closed-loop control technology

– Fundamentals of closed-loop control technology

– Expansion of measuring chains into closed-loop control circuits

– Analysis of regulated systems

– Use of regulators

· Troubleshooting

– Systematic troubleshooting of a process system

– Inspection, maintenance and servicing of process systems

Learning objectives

· Become familiar with the setup and the mode of operation of the fill-level system.

· Read and expand flow diagrams.

· Read and expand simple electrical circuit diagrams.

· Become familiar with the setup and mode of operation of a pressure gauge.

· Become familiar with the setup and mode of operation of a pump.

· Become familiar with the setup and mode of operation of a flow sensor.

· Record and analyse characteristic curves.

· Become familiar with the terms “open-loop control” and “closed-loop control”.

· Become familiar with the concepts of discontinuous control (2-step control) and continuous control.

· Become familiar with the essential work steps in the field of plant construction, from planning to

operation.

References to German school syllabi and vocations

Type of school Planning, engineering, assembly, marketing

Commissioning, production system

Open-loop control technology

Closed-loop control technology

Secondary schools, 10th grade SU 2 SU 2

Vocational secondary schools,

9th grade

SU 2, 4 SU 2, 4 SU 2, 4 SU 4

Vocational secondary schools,

10th grade

SU 1 SU 1 SU 2 SU 2

SU = syllabus unit

Introduction


Vocations according to learning content

Planning, engineering, assembly, marketing

Commissioning, production system

Control technology Regulation technology

System engineer LC 7 LC 8, 9 LC 10, 11 LC 10, 11

System technician, sanitary,

heating and air-conditioning

LC 5, 6 LC 7 LC 10 LC 10

Chemical laboratory technician LC 12 LC 12

Chemical technician LC 4 LC 4, 5 LC 8 LC 5, 8

Electronics technician LC 6 LC 3 LC 7

Electronics technician for

automation

LC 10 LC 10 LC 6, 7 LC 10

Qualified personnel for water

supply technology

LC 4, 13 LC 4 LC 4, 14 LC 4, 14

Precision mechanic LC 8, 16a LC 8, 16a

Industry mechanic LC 6 LC 13

Mechatronics technician LC 10 LC 9 LC 4, 7 LC 7

Pharmaceuticals technician LC 7 LC 7

Process technician for glass

technology

LC 9 LC 13

LC = learning content

Teachware, EduKit PA process automation project kit including evaluation of learning objectives

Introduction


Hardware flow chart, EduKit PA process automation project kit

Introduction


Sample room layout

Introduction


Classification into groups within the product range

Important note

The fundamental prerequisites for the safe use and trouble-free operation of the EduKit PA project kit

include knowledge of basic safety precautions and safety regulations.

This workbook includes the most important instructions for the safe use of the EduKit PA project kit. In

particular, the safety precautions must be adhered to by all persons working with the EduKit PA project

kit.

Furthermore, all pertinent rules and regulations for the prevention of accidents, which are applicable at

the respective location of use, must be adhered to.

Introduction


Obligations of the operating company

The operating company undertakes to allow only those persons to work with the EduKit PA project kit who:

· are familiar with the basic regulations regarding work safety and accident prevention and have been

instructed in the use of the EduKit PA project kit, and

· have read and understood the section concerning safety and the safety precautions.

· In the event that the EduKit PA project kit is not monitored by the operating company itself, an

appropriate person must be designated who, on the basis of his technical qualifications, is capable of

evaluating the functionality of the station as well as the dangers which result therefrom, for himself and

all trainees.

All staff should be tested at regular intervals on their safety-awareness at work.

Obligations of the trainees

All persons who have been entrusted to work with the EduKit PA project kit undertake to complete the

following steps before beginning work:

· Read the section on safety and the safety precautions in this manual

· Familiarise themselves with basic regulations regarding work safety and accident prevention

· Familiarise themselves with the specific dangers associated with compressed air, without which the

equipment would not be feasible, and accordingly ensure their own safety

· Disconnect the station from mains power when cleaning work or inspections are requested by the

person in charge.

Risks associated with the modular production system

The EduKit PA project kit is laid out in accordance with the latest state-of-the-art technology as well as

recognised safety rules. Nevertheless, life and limb of the user and third parties may be at risk and the

machine or other property may be damaged during its use.

The EduKit PA project kit may only be used:

· For its intended purpose

· When its safety functions are in perfect order

Faults which may impair safety must be eliminated immediately!

Guarantee and liability

Our “general terms and conditions of sale and delivery” always apply. These are made available to the

operating company no later than upon conclusion of the sales contract. Guarantee and liability claims

resulting from personal injury and/or property damage are excluded if they can be traced back to one or

more of the following causes:

· Use of EduKit PA project kit for other than its intended purpose

· Incorrect assembly, commissioning and/or operation of EduKit PA project kit

Introduction


· Use of the EduKit PA project kit with defective safety equipment or with incorrectly attached or non-

functioning safety and protective equipment

· Non-compliance with instructions included in the manual with regard to transport, storage, assembly,

commissioning, operation, maintenance and setup of the EduKit PA project kit

· Inadequate monitoring of system components which are subject to wear

· Improperly executed repairs

· Disasters resulting from the influence of foreign bodies and acts of God

Festo Didactic hereby excludes any and all liability for damages suffered by trainees, the training company

and/or any third parties, which occur during use of the system in situations which serve any purpose other

than training and/or vocational education, unless such damages have been caused by Festo Didactic due to

malicious intent or gross negligence.

Use for intended purpose

This station has been developed and manufactured exclusively for training and vocational education in the

fields of automation and technology. The respective training companies and/or trainers must ensure that all

trainees observe the safety precautions which are described in the accompanying manuals.

Use for intended purpose also encompasses:

· Compliance with all instructions included in the manual

· Completion of inspection and maintenance tasks

Safety precautions

General

· Trainees should only work at the station under the supervision of a trainer.

· Observe specifications included in the data sheets for the individual components and in particular all

safety instructions!

· Teachers and trainers must be capable of assessing the experiments they supervise or execute with

electrical energy, as well as any potential danger using their knowledge and training (e.g. with regard to

their own specialty, regulations and standards).

Electrical

· Electrical connections must only be established and interrupted in the absence of voltage!

· Use low-voltage only (max. 24 V DC).

· Correct polarity must be assured when connecting certain electrical components, especially sensors.

These components may be destroyed in the event of polarity reversal or short-circuiting.

· Electrical components are pre-wired at the factory, and are mounted onto an H-rail for direct attachment

to the rectangular profile. Alternatively, they can be shipped unwired as a kit. In either case, wiring work

must only be carried out by qualified personnel.

Introduction


· Do not pour water over any electrical components. If water is inadvertently poured over electrical

components, switch supply power off immediately. The entire system must be inspected for possible

damage by a teacher or trainer in this case.

· Avoid overloading the digital outputs with excessive current. Maximum current consumption of the

actuators used must be determined before they are connected.

Pneumatics

· Set system pressure to a value between 3 and 6 bar to operate the 2-way ball valve with a pneumatic

semi-rotary actuator. Do not exceed the maximum permissible pressure of 800 kPa (8 bar).

· Do not activate compressed air until all of the tubing connections have been completed and secured.

· Do not disconnect tubing while under pressure.

Mechanical

· Mount all of the components onto the profile plate.

· Make sure that piping and screw connections are carefully secured.

Process engineering

· Always fill the lower tank in the voltage-free state!

· Switch the 24 V DC supply power off and disconnect the power supply unit from the power supply (230

V DC).

· Use potable tap water (recommended), which ensures long-term, maintenance-free operation of the system.

· The maximum permissible operating temperature of +65° C for the tank must not be exceeded.

· The maximum permissible operating pressure of 0.5 bar for the liquid in the tubing may not be exceeded.

· The pump must not be allowed to run dry. The pump must not be used with seawater, contaminated

liquids or viscous media.

· Empty the liquid from the system by opening the drain valve after completing the experiments or before

changing the piping layout.

· Inspect the liquid and replace it at least once a week if contaminated.

· Clean the system as required, but in any case at least once a week. Do not use aggressive cleaning

materials or scouring agents.

· The liquid ages if the system is left at a standstill for a lengthy period of time. Always empty the tanks

and the piping before leaving the system at a standstill for a long period of time.

· No liquids must be allowed to remain in the system for long periods of time, because this may result in

the growth of bacteria such as the so-called legionellae.

Introduction


Technical data, system

Max. operating pressure in piping 50 kPa (0.5 bar)

Power supply for the station 24 V DC / 4.5 A

Profile plate 350 x 200 mm

Station height: with one tank

with two tanks

670 mm

1090 mm

Inside dimensions of the Systainer 490 x 360 x 272 mm (H x W x D)

Volumetric flow rate of the pumps 0 to 6 l/min.

Clean water tank Max. 3 litres

Flexible piping system DN15 (Æ 15 mm)

Transport

The EduKit PA project kit is shipped in a Systainer.

The freight forwarder and Festo Didactic must be notified without delay of any damage that occurred in

transit.

Unpacking

Carefully remove the filler material from the Systainer when unpacking the project kit. When unpacking the

project kit, make sure that none of the parts are damaged.

Examine the station for possible damage after unpacking. The freight forwarder and Festo Didactic must be

notified of any damage without delay.

Scope of delivery

Check delivered items against the packing slip and your purchase order. Festo Didactic must be notified of

any deviations without delay.

Visual inspection

Each time the system is started up, it must first be inspected visually.

Perform the following inspections before starting the EduKit PA project kit:

· Inspect electrical connections and wiring.

· Check piping, pipe connectors and pneumatic components, including tubing for correct fitting, leak-

proof sealing and condition.

· Check mechanical and pneumatic components for visible defects (cracks, loose connections etc.).

Eliminate any damages discovered during inspection before starting the station!

All regulations and instructions must be adhered to in order to ensure correct operation of the EduKit PA

project kit.

Introduction


Maintenance

The EduKit PA project kit is largely maintenance free. The following steps should be carried out at regular

intervals:

· Clean the entire project kit with a soft, lint-free cloth and check components for freedom of movement.

· Inspect liquid for contamination! The liquid may age if the project kit is left unused for any length of

time.

· The system should be drained completely if it is not used for a long period of time.

Updates

Current information on and supplements to the technical documentation for the EduKit PA project kit are

available on the Internet at www.festo-didactic.de/Service/MPS.

Introduction


© Festo Didactic GmbH & Co. KG A-1

Part A – Plant construction

1. Process description ________________________________________________________________ A-3

1.1 Technical reference _________________________________________________________________ A-3

1.2 Economic reference: market research __________________________________________________ A-6

2. Planning _________________________________________________________________________ A-9

2.1 Project management ________________________________________________________________ A-9

2.1.1 Work order, requirements specification ________________________________________________ A-9

2.1.2 Sequence planning and scheduling, project structure plan, performance specification ________ A-10

2.1.3 Purchasing materials and goods _____________________________________________________ A-13

2.1.4 Standards, regulations, data sheets __________________________________________________ A-14

2.1.5 Risk assessment __________________________________________________________________ A-21

2.2 Mechanical engineering ____________________________________________________________ A-22

2.2.1 Sketches and technical drawings ____________________________________________________ A-22

2.2.2 PI flow diagram ___________________________________________________________________ A-26

2.2.3 Parts list, mechanical ______________________________________________________________ A-28

2.2.4 Assembly plan, mechanical _________________________________________________________ A-29

2.2.5 Quotation and cost calculation ______________________________________________________ A-31

2.2.6 Test report _______________________________________________________________________ A-33

2.3 Electrical engineering ______________________________________________________________ A-35

2.3.1 Electrical circuit diagram ___________________________________________________________ A-35

2.3.2 Parts list, electrical ________________________________________________________________ A-36

2.3.3 Assembly plan, electrical ___________________________________________________________ A-37

2.3.4 Cost calculation ___________________________________________________________________ A-38

2.3.5 Test report _______________________________________________________________________ A-40

3. Installation ______________________________________________________________________ A-43

3.1 Work safety ______________________________________________________________________ A-43

3.2 Preassembly, mechanical ___________________________________________________________ A-44

3.3 Pre-wiring, electrical _______________________________________________________________ A-44

3.4 Final assembly with component labelling ______________________________________________ A-45

4. Commissioning ___________________________________________________________________ A-47

4.1 Mechanical testing, report __________________________________________________________ A-47

4.2 Electrical testing, report ____________________________________________________________ A-48

4.3 Overall commissioning _____________________________________________________________ A-49

4.4 System analysis: evaluation of test reports ____________________________________________ A-50

4.5 Shipping and product approvals, performance description _______________________________ A-50

Introduction

A-2 © Festo Didactic GmbH & Co. KG

5. Marketing and sales ______________________________________________________________ A-51

5.1 Quotations _______________________________________________________________________ A-51

5.2 Product presentation ______________________________________________________________ A-52

5.3 Documentation ___________________________________________________________________ A-52

5.4 Intellectual property rights __________________________________________________________ A-53

6. Evaluation of learning objectives for plant construction _________________________________ A-55


1. Process description

1.1 Technical reference

Information

The subject of plant construction will be examined in greater detail on the following pages. Although plant

construction encompasses several individual disciplines, they can be seen as a whole. Learners will be

introduced to the most important aspects of plant construction using a consistent method based on

practical examples. The knowledge acquired also provides them with an overview of the interaction which

takes place between a variety of professions, such as electrical engineering, mechanical engineering and

process engineering. The overall concept of the MPS-PA project kit is also intended to support the

vocational orientation of pupils and trainees and to encourage young people to pursue technical careers.

General learning objectives

Participants are familiarised with the following topics:

· Project management


· Mechanical and electrical engineering

· Creating flow diagrams and simple circuit diagrams

· Analysing results

· Mechanical and electrical assembly and wiring

· Commissioning with test report

· Marketing and sales



Information

Changing and maintaining fill levels are common daily tasks. These processes usually take place in the

background or within areas of a machine or system that is not immediately visible. Nevertheless, monitoring

process quantities such as fill level, pressure and flow rate offers a great deal of potential. Economy,

improved quality and more safety for personnel and machinery are only a few of the aims which can be

achieved by consistent process monitoring. Below are a few examples of applications in which these factors

play a role.

Pressure monitoring

Example: galvanising plant

The acid bath at a galvanising plant is continuously recirculated and filtered. A filter in the piping system

ensures that contamination and particles are removed. During operation, the contamination is deposited on

the filter and resistance within the piping system increases. As a result, pressure upstream of the filter rises.

Pressure is monitored via a sensor. When a specified pressure is exceeded, the filter must be cleaned or

replaced.



Flow monitoring

Example: water meter

A household water meter continuously measures the occupants’ water consumption by measuring the flow

rate in the fresh water supply line. The consumer relies on a uniformly accurate read-out of actually

consumed quantities. The water utilities are also dependent on the accuracy of the water meter. Deviation

results in a loss for one party and an erroneous gain for the other.

Fill level monitoring

Example: water tower

In order to ensure a constant supply of drinking water, ground, spring or lake water is pumped into water

towers where it’s stored before being distributed to cities and communities. The fill levels in these towers

should be kept as constant as possible, although varying amounts of water are withdrawn by households.

Water flows from the water towers via distributors into the storage tanks of domestic household water

systems. From there it is accessed directly via a water tap or it’s stored again, for example in toilet tanks.



Further examples of pressure, flow and fill level monitoring:

· Pressure must be held constant in water jet cutting systems, even in the event of fluctuating water demand.

· A certain amount of water must be added in order to achieve the desired consistency in a cement mixing

system. The volumetric flow rate is time-controlled and flows constantly.

· Cooling lubricant is pumped into a tank at the machine in order to ensure an uninterrupted supply to

machine tools. Cooling lubricant is withdrawn continually during the machining process. The fill level is

continuously monitored.

· Pumps deliver cooling water from car radiators to car engines in order to prevent them from overheating. A

storage container compensates for volumetric fluctuation due to thermal expansion and loss.

· Liquids are pumped from one tank to the next for storage in filling systems. When a given quantity of

liquid is withdrawn, for example, the fill level has to be evened out.

· Fountains are operated with the help of a pump and a storage tank.

1.2 Economic reference: market research

Information

There are approximately 14,500 water catchment systems in Germany. More than 60% of drinking water is

ground water; the rest comes from rivers, lakes, bank filtrate and springs.

For example, the supply of water for Baden-Württemberg is assured by a joint management authority

consisting of communities, cities and water utilities, namely Bodensee-Wasserversorgung (Lake Constance

water supply). Roughly four million people are supplied with water from Lake Constance, which is pumped

from a depth of 60 metres near the town of Sipplingen. Approximately 130 million m3 of water are

transported through a piping network that is 1700 kilometres long and includes roughly 30 tanks used for

intermediate storage. The largest water tank, with a capacity of 100,000 m3, is located in Baden-

Württemberg’s capital city, Stuttgart.

Task

– Find out about water supply in your city or area.

– Determine the course of the water before it arrives at all the households.



Information

The fill-level system simulates the supply of water from the withdrawal of raw water, for example from a

spring, to the filling of a water tower with the help of a pump up to consumption by households. Two tanks

are available for this project, one of which represents the elevated water tower, and the other the

household’s domestic water tank. The water has to be pumped into the water tower by means of an impeller

pump.

Volumetric flow rates, pressures and fill levels need to be recorded at the system. Variable valve settings

and electrical voltages are used in order to do this.


2. Planning

2.1 Project management

2.1.1 Work order, requirements specification

Information

The system is shipped as individual components and must be set up on-site, both mechanically and

electrically. Various experiments should be carried out, documented and assessed after the system has

been fully set up and tested. The following services, work sequences and documents are specified in the

work order to this end by the customer:

· Mechanical design

· Documentation (text and images)

· Develop and create circuit diagrams

· Generate parts lists/list of components

· Develop an assembly plan

· Plan and carry out wiring and connection of electrical components

· Determine material costs

· Prepare a presentation on the subject of water supply

· Create an approval checklist and report

· Design and implement a graphic evaluation

· Calculate, record and evaluate time required for activities

· Create data sheets for recording measured values

· System commissioning

· Measured value acquisition as an experiment

· Process calculations and technical questions

· Create technical drawings

· Produce components if necessary

2. Planning


2.1.2 Sequence planning and scheduling, project structure plan, performance specification

Information

First of all, in the planning the various tasks, as listed on the work order and the requirements specification,

must be organised and divided in the order in which they will be carried out. The requirements specification

is prepared by the customer and includes all the services to be rendered. The supplier creates the

performance specification on the basis of the stipulations set forth in the requirements specification. In it,

the supplier records the services to be rendered, the activities to be carried out, important dates for

presentations and meetings etc., deadlines for partial and full performance of the obligations and a project

structure plan. The project plan lists the respective activities arranged according to sets of tasks in the form

of a flow chart. These sets are subsequently arranged interdependently in chronological order. This

schedule is called the project sequence plan. The activity lists indicates the planned duration of each step

before the next one can be started.

Task

The performance specification should be put together during the concept phase (see worksheet for

shipment of a completed and functional fill-level system with two tanks). The performance specification is

enhanced during the planning phase.

– Complete the performance specification worksheet (concept phase).

– Create a project structure plan and use it to develop your project sequence plan with the required

procedures in tabular format with a rough time estimate. Use the list of services to be rendered from the

work order for orientation.

– Assemble a project team for the various tasks.

– Use the performance specification to describe the objectives of the project, the people involved, the

quality requirements with regard to setup and functionality of the system, general conditions,

deadlines, milestones and the scope of documentation.

2. Planning


Performance specification

Project name/designation:

Order no.

Customer:

Project employees:

Project no.

Schedule: Intermediate deadlines:

Assembly deadlines:

Completion deadline:

Terms and conditions of

payment:

o Advance payment:

o According to payment schedule:

Concept phase

Description of the product

Description of the range of

applications

Description of the function

Formulation of the

problem/requirements

Done

Technical data

Costs and target prices

Planning phase

Preliminary calculation of

manufacturing costs

Personnel and material costs

Project costs

2. Planning


Item Step designation Duration in days

Preceding activity

Team members

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

Project sequence plan

2. Planning


2.1.3 Purchasing materials and goods

Information

Two important aspects of the planning phase include the procurement of materials and goods. These steps

should be planned carefully and in detail. The timely completion of a project may depend on this in some

cases.

The first step of purchasing materials and goods involves finding a suitable supplier. A suitable supplier can

be selected using the Internet, as well as visits to, and meetings with, potential suppliers.

As a rule, the following steps are completed after selecting a supplier:

· Issue an RFQ:

At this point, product specifications need to be clarified and prices, lead-times and terms and conditions

of payment and delivery have to be negotiated.

· Issue a purchase order:

It’s important to include the correct information on the purchase order. This includes a precise product

designation, the quantity, the price and the delivery date, as well as terms and conditions of shipping

and payment.

· Dispatch the order confirmation:

The supplier sends you an order confirmation after he has received your purchase order.

· All the points which were agreed upon before the order was placed should be reviewed at this time.

Important points include the product designation, the price, the quantity, lead-time and terms and

conditions of payment.

· The goods arrive:

Goods are usually received by the good inwards department, where the shipment is inspected for

damage and/or defects. If any defects are detected, they must be recorded and documented. The

resulting documents must then be submitted to the liable party, i.e. the manufacturer or the supplier.

· The invoice arrives:

Before the invoice amount is finally paid, the prices on the invoice are compared with the prices on the

purchase order in order to rule out any possible errors. The order is closed once the invoice amount has

been paid.

· Carry out final costing:

The purchasing costs are used for final costing. This step is helpful to estimate future projects.

2. Planning


2.1.4 Standards, regulations, data sheets

Information

A process engineering system consists of numerous components from various manufacturers. The

components must comply with uniform quality standards. These standards are specified in accordance with

DIN and EN, as well as ISO, VDE and VDI.

The following standards are taken into consideration and the following data sheets are required to plan and

design the fill-level system in accordance with current knowledge as of 2008:

· DIN 10628 – standard for graphical symbols and flow diagrams for process plants

· DIN 19227, parts 1 and 2 – standard for the graphic representation of process, measurement and

control technology symbols

· DIN EN 22858 – standards for graphical symbols and identifying letters for mechanical components

· DIN EN 61346-2 – standards for graphical symbols and identifying letters for electrical components

· DIN ISO 1219-2 – standards for graphical symbols and identifying letters for pneumatic components

· Data sheets for piping, stopcocks and the impeller pump

· DIN EN 60617, DIN EN 61346-2 – standards for graphical symbols and identifying letters ...

· DIN ISO 1219, DIN EN 60848 – standards for engineering drawings of pneumatic components and

function charts

The standards and stipulations set forth by DIN and VDE as well as the safety precautions for working with

electrical current and voltage, must be observed for all electrical work.

Technical information about the components is included in the data sheets on CD-ROM.

Electrical components

The respective devices are designated in the electrical circuit diagrams in accordance with DIN EN 61346-2.

Type of equipment Identifying letter

Actuators (servo drive, actuating coil, electrical motor, linear motor) M

Diodes R

Auxiliary relays K

Terminals, terminal blocks, terminal strips X

Capacitors C

Circuit breakers, isolating switches Q

Power transistors Q

Indicators (mechanical, optical, acoustic) P

Relays K

Tubes, semiconductors

Contactors (for load) Q

Sensors in general, position switches, proximity switches, proximity sensors etc. B

Fuses F

2. Planning


M

OUT

0V

24V

IN

Anl

aufs

trom

-be

gren

zer

curr

ent l

imit

er

2A2

4.9/

24V

B

4.9/

0VB

24VA

_EX

T

/6.7 2C01

0V

A_E

XTXMA

29

XA

224

VA

XA

20V

A

XMA

21

1

2X4

10 24VA

/6.7 AGNDA

D D

Brü

cke

um

stec

ken

für:

Dig

ital

/Ana

log

Ans

teu

eru

ng

use

bri

dge

to

ch

oo

se d

igit

al/a

nalo

g co

ntr

ol

0VA

12

A A2A4

- (G

ND

)

A2

(AN

L)

R+

+

R-

43M

otor

Ans

teue

rung

Mot

or c

ontr

ol

XMA

21

XA2

O0

A1(

STA

RT)

0VA

1

2K10 7.

5

11 14

M2M

1

+-(

bk)

2

2 O1

1114

.4

2K1

+ 0VA

2K10 7.

5

21 22 7.7/ERR

24

2K1 .3

11 14

2M2+

2M3

+ 0VA

2M4

4 O3

0VA

2M

5

5 O4

0VA

6 O5

0VA

7 O6

0VA

BN

BU

BK

2PA

_ B

USY

+8 O7

0VA

/6.0

24V

B /6.0

0VB24

VA

0VA

FED

24VA

24V

0V

0VA

3 O2

++

Example of an electrical circuit diagram – MPS® PA mixing station, outputs

2. Planning


Pneumatic components

Pneumatic components are designated in circuit diagrams in accordance with DIN ISO 1219-2. All the

components included in any given circuit have the same primary identifying number. Letters are assigned

depending on each respective type of component. Consecutive numbers are assigned if several components

of the same type are included within a single circuit. Pressure lines are designated with a P and are

numbered separately.

Actuators: 1A1, 2A1, 2A2 ...

Valves: 1V1, 1V2, 1V3, 2V1, 2V2, 3V1 ...

Sensors: 1B1, 1B2 ...

Signal input: 1S1, 1S2 ...

Accessories: 0Z1, 0Z2, 1Z1 ...

Pressure lines: P1, P2 ...

Identifiers for pneumatic components also include a system number (“1-... ... ...”) which appears to the left

of the circuit number, the component identifier and the component number.

2. Planning


1M

1

1M

4

1

12

3

2

BN

BK

BU

RU

1 4 3

WH

2R

I

UP

1B

1

1V

1

1-2V

1

1-2V

21-

2V3

V103

V10

21-

1A1

_1B

9

_1B

7

_1B8

_1B6

13

SOLL

IST

2

PE

PRO

P_V

1-1V

3

max

. 2b

ar

1-1V

2

I

14

24

35

11

M5

1-3V

1

1-3V

21-

3V3

14

24

35

1

1-3A

1

V10

6

1M

6

1-4V

1

1-4V

21-

4V3

14

24

35

1

1-4A

1

Example of a pneumatic circuit diagram – MPS® PA filtering station

2. Planning


Process engineering components

Components are designated in the PI flow diagram in accordance with EN ISO 10 628 and DIN 19227-1.

M

P202

V207

V209

V211

B20

4

LS+

LA+

205

212

LS-

206

V210

M

P201FI FIC

202

201

LS-

204

B20

3

V203V2

04

LA+

211

LS-

203

B20

2

V205

V202

LA+

210

LS-

202

B20

1

V206

V201

LS+

201

LA+

213

V208

X201

X202

Example of a PI flow diagram – MPS® PA mixing station

2. Planning


EN ISO 10628 standard

The layout and function of a process engineering system are described in a piping and instrument flow

diagram (abbreviated PI flow diagram).

Apparatus or machinery Identifying letter

System section or machine if not assigned to one of the following groups A

Container, tank, hopper, silo B

Chemical reactor C

Steam generator, gas generator, oven D

Filtration device, liquid filter, sieve, separator F

Gear unit G

Lifting unit, conveying unit, transfer unit H

Column K

Electrical motor M

Pump P

Stirrer, stirring container with stirrer, mixer, kneader R

Centrifuge S

Dryer T

Compressor, vacuum pump, fan V

Heat exchanger W

Feed and separating equipment, other devices X

Actuator unit, other than electrical motor Y

Crusher Z

Identification of process engineering components

DIN 19227-1 standard

In addition to system components, process, measurement and control points are also included in PI flow

diagrams. The process related functions of the measured quantities are described by means of process,

measurement and control points per DIN 19227-1. The identifier should indicate the measured quantity or

another input quantity, how it’s processed, its direction of control action and its specified location.

A process, measurement and control point consists of a circle and is designated with an identifying letter (A to

Z). The identifying letters are entered in the top part of the circle and numbering is entered in the bottom part.

The order of the identifying letters is as per the table, “Process, measurement and control identifying letters

per DIN 19227-1”.

Example L I C

Lic

First letter Supplementary letter First subsequent letter

Fill level Display Automatic control

2. Planning


The identifying procedure for process, measurement and control points is freely selectable. Consecutive

numbering is advisable because each process, measurement and control identifier may only be used once,

even if there are several measuring points with the same measured quantity.

Further information can be found in DIN 19227, part 1.

Process, measurement and control identifying letters per DIN 19227-1

Letter Measured quantity or other input quantity, actuator “Processing

Subsequent letter Sequence: O, I, R, C, S, Z, A”

First letter Supplementary letter

A Error message

B

C Automatic control

D Density Difference

E Electrical quantities Sensor function

F Flow, throughput Ratio

G Distance, length, position

H Manual entry, manual intervention Upper limit value (high)

I Display

J Sensing of measuring points

K Time

L Level (also separation layer) Lower limit (low)

M Moisture

N

O Visible sign, yes-no statement

P Pressure

Q Material characteristics, quality Integral, sum

R Radiometric quantities Recording

S Speed, frequency Switching, sequence control, logic control

T Temperature Measuring transducer function

U Combined quantities Combined actuator function

V Viscosity Actuator function

W Weight, mass

X Other quantities

Y Calculation function

Z Emergency intervention, protection by means of

triggering, safety device, safety relevant message

+ Upper limit value

/ Intermediate value

– Lower limit value

2. Planning


Task

– Familiarise yourself with the standards and data sheets.

– Which information do the above mentioned standards and data sheets provide you with?

– Create a summary of the most important characteristics for each standard and the components used.

2.1.5 Risk assessment

Information

An important aspect of the planning phase is the risk assessment. All machinery and equipment

manufacturers are required to carry out a risk assessment for their machines and equipment. This is a legal

requirement and is stipulated in the EC machine directive. The directive states: “The manufacturer of

machinery or his authorised representative must ensure that a risk assessment is carried out in order to

determine the health and safety requirements which apply to the machinery. The machinery must then be

designed and constructed taking into account the results of the risk assessment.”

Below is an example of what a risk assessment might look like.

2. Planning


2.2 Mechanical engineering

2.2.1 Sketches and technical drawings

Task

– The scale of the overall drawing of the fill-level system is 1:5. Add the most important assembly

dimensions to the drawings so that it can be used later to set up the system.

Topview

2. Planning


Front view

2. Planning


Side view, right

2. Planning


– The rectangular profiles to which the tanks are attached are joined with retaining plates. Manually

sketch out the hole pattern for the retaining plates for M5 socket head screws.

– The retainer for the impeller pump has to be made. Calculate the length of the sheet metal.

a, b, c ... Lengths of bending sections

n number of bends

v compensation value; v = 3 mm for a sheet metal thickness of 1 mm and a bending radius of 4 mm

L = a + b + c + ... - n · v

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

2. Planning


2.2.2 PI flow diagram

Information

The piping and instrument flow diagram (PI flow diagram) depicts the technical equipment included in a

system with the help of graphical symbols which are connected using lines. The graphical symbols represent

the system components and the lines identify lengths of pipe, as well as electrical functions and signals for

process measurement and control.

The designation V101 from the PI flow diagram is a process designation. Process related tasks are described

in a process, measurement and control plan using graphical symbols, i.e. process, measurement and control

points. The identifier should indicate the measured quantity or another input quantity, how it’s processed,

its control action and its specified location. A process, measurement and control point consists of a round,

oval or hexagonal symbol and is assigned an identifying letter (A to Z). The identifying letters are entered in

the top part of the symbol and a number is entered in the bottom part. The order of the letters is specified in

the table entitled “Identifying letters for process, measurement and control technology” per DIN 19227.

Task

– Fill in the missing designations.

– Create a PI flow diagram for the system using the components from the table.

Components list

Identification Graphical symbol Meaning of the graphical symbol

B101

V102

Stopcock

FI101

PI103

Pressure measuring point with display

P101

2. Planning


PI flow diagram

PI flow diagram, EduKit PA project kit

2. Planning


2.2.3 Parts list, mechanical

Task

The components and their required quantities can be determined from the overall drawing and the PI flow

diagram for the purpose of creating a parts list. The part numbers are included in the data sheets and the

Festo Didactic product catalogue.

– Using this information, create a parts list for the basic mechanical setup of EduKit PA without electrical

components.

2. Planning


Item Quantity Name Part number

2.2.4 Assembly plan, mechanical

Information

In order to keep assembly of the system as simple as possible, components are grouped into sub-

assemblies.

Task

– Create an assembly plan for the basic setup of the fill-level system using the table on the next page.

– Write out a set of procedures, indicating how you would assemble the system. Sub-assemblies are

numbered consecutively with the designations B1, B2 and so forth. (The “Times” column refers to a task

in a later chapter and can be disregarded for this exercise.)

2. Planning


Sub-assembly

Item Work step Tool Work step carried out

Times

Assembly plan, mechanical

2. Planning


2.2.5 Quotation and cost calculation

Information

A fill-level system is required in another department within your company for training purposes. First of all,

you’ll produce a complete basic setup in the form of a prototype in the training department. The fill-level

system will then be sold to the respective department. Determine an estimated sales price in the form of a

simple cost calculation. Electrical and mechanical components should be listed separately. Use the

following quotation as a basis for your calculation:

Item Quantity Designation Unit price Amount

1 1 Basic mechanical components kit with aluminium

profiles, including all accessories

125.00 €125.00

2 2 Tank, MPS-PA-B tank, round 201.00 €402.00

3 1 Pump, 170712 474.00 €474.00

4 1 Flow meter, 691225 145.00 €145.00

5 1 Pressure gauge 15.90 €15.90

6 2 m Pipe, 304518 8.60 €17.20

7 5 Push-in connector, 170701 4.20 €21.00

8 5 T-distributor, 170702 5.00 €25.00

9 4 Push-in bracket, 690590 5.60 €22.40

10 6 Stopcock, 170703 19.70 €118.20

11 2 Blanking plug, 170705 1.90 €3.80

Net price €1369.50

Quotation (sample prices are not the same as actual prices!)

Task

– Calculate the costs for the fully assembled mechanical portion of the system. Costs are calculated

separately for the mechanical and electrical parts while the cost calculation for the electrical

components will be completed later (see 2.3.4). The prices of the components can be taken from the

above quotation. Manufacturing wages and overheads, as well as administrative and sales costs can be

based on figures provided by the appropriate people in your company, researched on the Internet or

estimated for the purposes of a rough calculation. Make a rough estimate of the time required for

assembly in order to determine labour costs. Use local hourly rates for this.

2. Planning


Term Explanation Pieces, hours Amount Total

Material costs (1) Procurement costs for materials,

components

Material overhead costs (2) Purchasing costs, warehousing costs,

bookkeeping

5% of (1)

Gross material costs (3) Total of (1) + (2)

Manufacturing wages (4) Wage costs allocated to the product

Manufacturing overhead costs (5) Depreciation, social security costs,

training costs, auxiliary materials, tools,

premises, payroll accounting

Manufacturing costs (6) Total of (4) + (5)

Special manufacturing costs (7) Production, fixtures, outsourced

processing (e.g. hardening)

Production costs (8) Total of (3) + (6) + (7)

Administration and sales (9) Administration, taxes, advertising costs 15% of (8)

Cost of sales (10) Total of (8) + (9)

Profit (11) . . . % of (10)

Net sales price Sales price without value added tax Total of (10) + (11)

Gross sales price Sales price with value added tax

Simple cost calculation for mechanical assembly

Task

– When you buy components, a difference is made between net and gross prices. What’s the difference?

Calculate the gross sales price for the above example.

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

– What’s meant by “overheads”?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

2. Planning


– What’s meant by manufacturing costs?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

2.2.6 Test report

Information

Once mechanical assembly has been completed, the fill-level system and all its components must be

inspected and approved (i.e. screw connections in the pipe fittings, straightness and parallelism of the

piping, tank mounting, profiles and the impeller pump).

In actual practice, test reports are used to document the functionality and the condition of the system. Test

report requirements are specified either by the customer or by currently valid standards.

Task

– Create a test and approval report with a word processing program which has space for the following

entries:

- Test points are numbered consecutively in a tabular report and the numbers are added to the

picture below.

- The list includes columns for each item number, the test point designation, a tick mark for approval

and comments.

- Space is provided at the end of the test report for the name of the inspector and the date.

- The comments column must provide adequate space for the entry of any defects detected during

inspection.

2. Planning


Mechanical assembly without electrical actuation

2. Planning


2.3 Electrical engineering

2.3.1 Electrical circuit diagram

Information

The impeller pump is turned on and off using a detented switch in the basic setup. The pump’s on/off status

is displayed by an indicator light. The impeller pump is supplied with 24 V DC power via a power supply unit.

Task

– Create an electrical circuit diagram for the system and identify all the components. All the system’s

electrical components must be designated in accordance with DIN EN 60617.

Circuit diagram

2. Planning


2.3.2 Parts list, electrical

Information

The parts list for the electrical components must be planned. The item numbers for the various components

are shown in the following figure.

Task

– Complete a part list for the entire electrical assembly. The part numbers can be taken from the data

sheets and the Festo Didactic product catalogue.

– Put a tick mark in the column “Components for basic setup” for each component required for this task.

– Which additional consumables will be required?

Estimate the amount.

2. Planning


Item no.

Quan-tity

Name Designation, standard designation

Components for basic setup

10

11

12

13

14

15

17

18

19

20

Blue wire, 0.5 sq. mm (cross section?) x

Cable binder (size?) x

Wire end sleeves

Bill of materials

2.3.3 Assembly plan, electrical

Information

To optimise work sequences, the order in which work steps are carried out to produce a product should be

planned and documented by the production planning department.

Task

– Arrange the work steps in a logical order with the help of the parts list.

List the wiring and assembly steps for the electrical components in the setup plan. Electrical

components are designated E1, E2, etc. (The “Times” column refers to a task in a later chapter and can

be disregarded for this exercise.)

2. Planning


No. Item no. Work step Tool Times

Assembly plan, electrical

– Add the connecting cables to the image of the electrical components to indicate how they have to be

wired according to the circuit diagram prepared earlier.

2.3.4 Cost calculation

Task

– On the basis of the quotation, determine an estimated sales price for the electrical components and

electrical wiring with the help of a simple cost calculation. Manufacturing wages and overheads, as well

as administrative and sales costs can be based on figures provided by the appropriate people in your

company, researched on the Internet or estimated for the purposes of a rough calculation. Make a

rough estimate of the time required for assembly in order to determine labour costs. Use local hourly

rates for this.

2. Planning



10 1 24 V DC indicator light with mounting bracket 17.00 €17.00

11 1 Electrical control switch with mounting bracket 17.00 €17.00

12 + 13 2 Electrical start pushbutton with mounting bracket 10.00 €20.00

14 1 Relay with two changeover contacts 18.00 €18.00

15 6 Screw terminals 1.07 €6.42

17 1 3-core safety laboratory cable 17.00 €17.00

18 1 Mountable plug block 2.90 €2.90

19 1 H-rail 1.90 €1.90

20 1 Rail for control components 24.00 €24.00

1 Table top power supply unit with power cable, 230 V AC,

24 V DC / 4.5 A

351.00 €351.00

Net price €475.22




components


bookkeeping

5% of (1)







Special manufacturing costs (7) Production, outsourced processing (e.g.

ready-wired components)




Profit (11) . . . % of (10)

Sales price Net price without value added tax Total of (10) + (11)

Calculation plan

2. Planning


2.3.5 Test report

Information

Once electrical assembly has been completed, the wiring, interconnection of the electrical components such

as switches and the indicator light and the mechanical attachment of the electrical components are

inspected and approved.

Task


entries:

- Test points are numbered consecutively in a tabular report and the numbers are added to the image

below.


and comments.



inspection.

2. Planning


Setup with electrical wiring

2. Planning



3. Installation

3.1 Work safety

Information

Work instructions specify in detail how certain steps have to be carried out. Work instructions are tied to a

specific process, a product or a workstation. They form the basis for ensuring that quality standards are met

when the company’s employees carry out their respective tasks. Initial basic instruction on safety in the

workplace and how each person should comply must be completed before specific work instructions are

handed out.

Observe the safety precautions in the introduction!

Safety instructions

Mr./Ms.

Department

Job

Received instructions in accordance with § 7 UVV, VBG 4 and on the basis of the activities carried out at the workstation.

Subject of instruction Date Instructed person (signature)

Supervisor (signature)

1. General instructions at the fill-level system

2. Instructions on handling liquids

3. Instructions for electrical components

4. Electrical start-up must only be carried out by

appropriately trained personnel.

5. General introduction to: Workshop use

Goods in/out

Working at a PC

Internet and e-mail

Telephone system

Accident prevention regulations specified by trade associations for precision and electrical engineering apply.

3. Installation


3.2 Preassembly, mechanical

Information

The components must now be assembled in accordance with the specifications in the assembly plan.

Task

– Complete the mechanical preassembly of the components of the fill-level system first. Supplement the

assembly plan you created in the chapter on “Planning” by assigning assembly procedures to

components. Use the technical drawings of the components as an assembly guideline. Engineering

drawings of the individual components are included on CD-ROM.

– Write down the assembly times in the assembly plan prepared earlier and modify it if necessary if you

use different steps or discover better alternatives.

3.3 Pre-wiring, electrical

Information

The components are preassembled in accordance with the basic electrical setup plan.

Task

– First of all, the electrical components are pre-wired. Proceed in accordance with the layout you have

already created. Follow the circuit diagram with regard to wiring. Then attach the electrical components

to the H-rail.

3. Installation


– Write down the assembly times and modify the assembly plan if necessary if you use different steps or

discover better alternatives. Make a note of any changes to the assembly plan.

3.4 Final assembly with component labelling

Information

All the mechanical and electrical components are put together in the final step.

Task

– During final assembly, screw or clamp all the mechanical and electrical components to the profile plate

and the rectangular profiles and connect the electrical components to each other (see CD-ROM).

– Supplement the components list with the component designations in accordance with the PI flow

diagram and the electrical circuit diagram. Write the designations of the components onto the adhesive

labels and attach them to the respective system components.

3. Installation


Item no. Graphical symbol Meaning of the graphical symbol Identification

1 P101

2

Measuring point for pressure

measurement with display (component:

pressure gauge)

PI103

3 FI101

4

7

Tank, container (2) B101, B102

Component list per PI flow diagram


10

Indicator light, start

11 S1

S1

12

Electrical pushbutton, start S2

13 S3

S3

14

Relay

Components list based on electrical circuit diagram


4. Commissioning

4.1 Mechanical testing, report

Information

The fill-level system has now been set up and should first of all be filled. Disconnect the system from the

power supply before commissioning. In order to prevent any unpleasant surprises, check the mechanical

components both before and during filling. Keep an adequate supply of rags on hand in order to mop up any

water which might escape.

Task

– Check the points listed below and acknowledge inspection.

Commissioning, report – mechanical

Characteristic, requirement for component Fulfilled Not fulfilled, comment

Stopcock V 105 closed

Impeller pump pipe connection complete and securely pushed in place

Stopcock V 101 for filling the upper tank from above closed

Stopcock V 103 for filling the upper tank from below closed

Stopcock V 102, lower tank return line, closed

Fill the upper tank, check for leaks

Check fittings and tighten further if required

Open stopcock V 102 (lower tank return line open)

Fill the lower tank, check for leaks


Place a bucket underneath, open stopcock V 105 and drain the tank

Inspector Date

4. Commissioning


4.2 Electrical testing, report

Information

Once mechanical inspection has been completed, the electrical components are tested to ensure they

function correctly. This is done by filling the system with water, so that the pump is prevented from running

dry. First, the water is only pumped around in a circular direction, i.e. from the bottom container via the

impeller pump and back into the lower tank from the upper tank.

Task

– Carry out all the commissioning steps.

– Evaluate your results and tick off the corresponding entry. If the function is not performed correctly,

make a note of the determined status or the sub-function. Discuss appropriate measures for eliminating

the cause of error with your trainer.

Commissioning, report – electrical

Function Fulfilled Not fulfilled, comment

Connect the 24 V and 0 V leads from the power supply unit to the terminals.

Electrical control switch wired

Indicator light wired

Pump wired

Secure wires with cable binder

Power supply unit connected to mains power (230 V AC)

Switch the power supply unit on, the indicator light on the power supply unit lights

up.

Control switch ON, indicator light switches on

Control switch ON, pump runs

Control switch OFF, indicator light does not switch on

Pump vented?

Control switch OFF, pump does not run

Power supply unit OFF, system is shut down

Inspector Date

4. Commissioning


4.3 Overall commissioning

Information

You have approved the system’s mechanical and electrical parts. Now start an initial, complete test run with

all of the system’s components.

Before each time you commission the system, carry out a visual inspection. Inspect the following before

starting the system:

· Electrical connections

· Correct fitting, leakproofness and condition of piping and pipe connectors

· Correct fitting and condition of compressed air connections, if pneumatic valves are used

· Mechanical components for visible defects (cracks, loose connections etc.)

· Fill level of tank B101

Eliminate any damage discovered during inspection before commissioning.

Supply the system with 24 V DC power via a mains power supply unit.

Task

– Carry out the following steps for (re-)commissioning:

1. Prepare the workstation.

2. Conduct visual inspection.

3. Inspect cable connections.

4. Activate supply power.

5. Fill the tanks.

6. Vent the piping system

– Set the stopcocks so that the following tasks can be carried out:

- Full upper tank B102 from above, stopcock V102 in tank B101 opened about 20%.

V101 open, V103 closed.

- Fill upper tank B102 from below, stopcock V102 in tank B101 opened about 20%.

Open V103, close V101.

4. Commissioning


4.4 System analysis: evaluation of test reports

Information

The test reports have to be analysed and conclusions must be drawn based on the work done while setting

the system up so that the system’s design and layout can be analysed and improvements made. The

commissioning test reports for mechanical and electrical components are available and overall

commissioning has also been completed.

Task

– Evaluate the test reports and pinpoint any problems.

Use the first practical test run to draw conclusions for further work with the system. Analyse the overall

layout of the system in order to determine whether or not the assembly and commissioning procedures can

be improved. Document your evaluations in writing.

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

4.5 Shipping and product approvals, performance description

Information

Once prototypes have been developed, the first samples are produced under series manufacturing conditions.

The product is not approved until the function, quality and performance features have been examined and

tested. Subsequent series manufactured parts must conform to the same quality standards as the first

samples.

The product must be approved by general management before it can be launched. All information relevant

for sales must be available as a basic prerequisite for the product’s introduction onto the market (see

chapter 5, “Marketing and Sales”).

4. Commissioning


5. Marketing and sales

5.1 Quotations

Information

A great variety of information is required in order to sell a product. For example, the text for a quotation

template must be prepared.

Task

– Find out how quotations are laid out and what information is included. Base yourself on the layout and

content of a quotation from your company or another manufacturer.

– Which details are included in a quotation?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

– Create a sample quotation for a customer who wants to purchase the project kit.

– What does the term “ex works” mean?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

4. Commissioning


5.2 Product presentation

Information

The way in which a product is presented plays an important role in how well it will sell. Companies invest

large sums of money in product marketing. The most important points are briefly discussed below.

Task

Various types of product presentations are created in small groups.

– Brochure, leaflet, foreign languages

A brochure or a leaflet should be printed for the project kit. Important content for any printed

information includes an overall view of the system, interesting partial views, a functional description,

features and technical data of the individual components and notes regarding the user-friendliness of

the piping system thanks to the push-in connector system.

Write the text for the functional description and the technical data in German and English, and add both

languages to the leaflet. The technical data for the various components are included on CD-ROM.

– Screen presentation

The system will be presented to a customer. Create a screen presentation which covers the most

important features and functions of the system. Use the texts for the brochure, but condense them for

the screen presentation. The screen presentation can also be laid out as a PDF file, so that it can be

printed out. Photos of the system are included on the CD-ROM.

– Internet presentation

Edit the screen texts and images so that they can be used in a start-up page for the Internet. Create an

HTML page for the project kit with the help of an HTML editor.

5.3 Documentation

Information

The technical documentation is intended to provide the recipient of the product with information and

instructions regarding the system or the product. In addition, the customer is also made aware of safety

precautions and provided with operating instructions for the system.

4. Commissioning


Task

– The entire project must be documented. The documentation should include the following information:

- System layout

- Description of functions

- Data sheets for the various components

- Experiment descriptions

- Tables with values and evaluations resulting from the experiments

- Findings

- Circuit diagrams

- Drawings

5.4 Intellectual property rights

Information

As a result of intellectual property legislation for the protection of industrial property rights, the holder of

the rights is granted the opportunity of prohibiting commercial exploitation of the protected objects by any

other party. The intellectual property rights are thus rights of prohibition. They are not – at least not

automatically – rights of use.

Task

– Which types of protective rights are there? Research this topic on the Internet.

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

4. Commissioning



6. Evaluation of learning objectives for plant construction

1. During which phase of system setup is the project structure plan used?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

2. What is the function of the project structure plan?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

3. Calculate the flat length for the pump bracket assuming a bending radius of 4 mm and a sheet metal

thickness of 2 mm. Use a compensation value of 4.5.

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

4. How are the following functions designated in a PI flow diagram?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

4. Commissioning


5. Sketch the graphical symbols for a PI flow diagram (see planning):

________________________________________________________________________________

____________________________________________________________________________________

_____________________________________________________________________________

6. Draw the PI flow diagram for pressure measurement while filling the upper tank from below.

4. Commissioning


7. Which information is included in a part list?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

8. What’s included in a tabular assembly plan?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

9. When you buy components, a difference is made between net and gross prices. What is the difference

between these prices?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

10. Name typical overheads.

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

11. What’s meant by manufacturing costs?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

4. Commissioning


12. During initial testing, you started the pump with a detented switch. Why is a detented start-up switch

impermissible in actual practice?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

13. Cite one safety precaution each for electrical, pneumatic and mechanical components and process

technology

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

14. Why is a commissioning report prepared after final assembly has been completed and before

commissioning? Cite two examples.

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

© Festo Didactic GmbH & Co. KG B-1

Part B – Practice-based learning: manual measurement, open-loop and closed-loop control

1. Manual measurement ______________________________________________________________ B-3

1.1 Project task: bath recirculation _______________________________________________________ B-3

1.1.1 Task description ___________________________________________________________________ B-3

1.1.2 Setting up the system, inspection _____________________________________________________ B-4

1.1.3 Experiment: mechanical pressure measurement _________________________________________ B-5

1.1.4 Evaluation and findings _____________________________________________________________ B-6

1.2 Project task: mixing system __________________________________________________________ B-9

1.2.1 Task description ___________________________________________________________________ B-9

1.2.2 Experiment: flow measurement ______________________________________________________ B-10

1.2.3 Evaluation and findings ____________________________________________________________ B-11

2. Manual open-loop control __________________________________________________________ B-13

2.1 Project task: controlling water supply using hand valves _________________________________ B-13

2.1.1 Task description __________________________________________________________________ B-13

2.1.2 Mechanical layout _________________________________________________________________ B-14

2.1.3 Setting up the system, inspection ____________________________________________________ B-16

2.1.4 Experiment: filling the upper tank from below __________________________________________ B-16

2.1.5 Experiment: filling the upper tank from above __________________________________________ B-17


2.2 Project task: controlling water supply using 2-way ball valve _____________________________ B-20


2.2.2 Mechanical layout, inspection _______________________________________________________ B-21

2.2.3 Plans ____________________________________________________________________________ B-22

2.2.4 Commissioning report _____________________________________________________________ B-25

2.2.5 Experiment: filling using a pneumatically controlled 2-way ball valve ______________________ B-26


2.3 Project task: electrical control of the pump in the water supply line ________________________ B-27



2.3.3 Relay circuit with pushbuttons ______________________________________________________ B-28

2.3.4 Electrical circuit diagram ___________________________________________________________ B-29

2.3.5 Electrical wiring and setup plan ______________________________________________________ B-30

2.3.6 Commissioning, electrical testing and report ___________________________________________ B-31

2.3.7 Experiment: filling while simultaneously withdrawing water ______________________________ B-32


2.3.9 Experiment: pump start-up performance and power _____________________________________ B-34


4. Commissioning

B-2 © Festo Didactic GmbH & Co. KG

3. Manual closed-loop control ________________________________________________________ B-37

3.1 From a control loop system to a control circuit _________________________________________ B-37

3.2 Project task: controlling the fill-level in the tanks _______________________________________ B-39



3.2.3 Experiment: manually keeping the fill level constant in the upper tank _____________________ B-40


3.2.5 Experiment: controlling the fill level using an analogue controlled pump ___________________ B-43


3.2.7 Experiment: pressure and flow control ________________________________________________ B-44


4. Evaluation of learning objectives for manual measurement, open-loop and

closed-loop control ________________________________________________________________ B-47


1. Manual measurement

1.1 Project task: bath recirculation

1.1.1 Task description

Information

Typical recirculating processes are used in all baths where liquids have to be filtered. For example, leisure

time applications include swimming pools and technical applications include acid baths and galvanising

plants. As the filter becomes more and more contaminated, resistance in the piping system increases

upstream of the filter in proportion to the degree of contamination. When a specified pressure is exceeded,

the filter must be cleaned or replaced. The relationship between resistance (degree of valve opening) and

pressure is determined by experimentation.

Task

– Modification in accordance with the PI flow diagram: modify the basic setup with two tanks so that the

experiments for manual measurement can be done using a single tank. Stopcock V103 represents the filter

for the purpose of the experiment. Filter permeability is simulated by opening and closing the valve.

M

P101

V102

PI103

FI101

V103

B101

V105



1.1.2 Setting up the system, inspection

Work step Done

Modify the piping layout in accordance with the photograph. Remove the piping to the upper tank and insert

blanking plugs into each of the push-in T-connectors.

Close stopcock V105.

Check to make sure that all piping connections are correct.

Check the piping connections to the impeller pump.

Make sure that the pressure gauge is installed directly downstream of the pump!

Fill tank B101 with 3 litres of water.

Connect the system to the power supply unit (24 V DC).

Test execution:

Stopcocks V103 and V102 are fully open and V105 is fully closed. The control switch is turned to the ON

position and the pump delivers water. Stopcock V103 is closed successively in the test setup.

After the experiment has been completed, pull out the main plug and remove the 4 mm safety cable from

the power supply unit.

The water must be drained from the system via stopcock V105 after testing.



1.1.3 Experiment: mechanical pressure measurement

Fill the tank and then start the pump. Stopcock V103 is open at first and is gradually closed. Stopcock V103

represents the filter for the purpose of experimentation. Filter permeability is simulated by opening and

closing the valve.

– Read pump pressure from the pressure gauge.

– Observe the volumetric flow rate at the sight glass in the flow meter.

Resistance (degree of valve opening) and pressure

Degree of valve opening as percentage, V 103

pe [bar] Q [l/min.]

Open 0.18

80% 0.32

60% 0.3

40% 0.26

20% 0.22

Closed 0.32



1.1.4 Evaluation and findings

Task

– Plot the pressure measured in the piping system relative to the degree of valve opening on the graph:

– How are pressure and volumetric flow rate within a piping system influenced when resistance within the

piping system is continuously increased?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

– Why doesn’t pressure continue to rise after the stopcock has been fully closed?

___________________________________________________________________________________________

___________________________________________________________________________________________

– Explain how an impeller pump works.

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________



– Why is it important to ensure that there’s no air in the pump?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

– Which types of pumps can be used in the field of process technology? Use information from various

manufacturers in order to research your answer. Create a table with typical characteristics, as well as

technical data and the range of applications, for a given type of pump.

Pump type (section drawing) Characteristics, technical data, range of applications



1.2 Project task: mixing system


Information

The ingredients fed to a mixing system are usually required in the defined quantity. Mixing systems of this

sort are used, for example, to mix cement. A corresponding amount of water must be fed to the cement

mixer in order to produce a specified concrete mix. The quantity is time-controlled. A prerequisite is that a

constant volumetric flow rate must be maintained, e.g. 60 litres per hour.

The relationships between resistance (degree of stopcock opening), the delivered amount of water and the

required amount of time can be determined by means of an experiment. Run the experiment using the

existing test setup with one tank.



1.2.2 Experiment: flow measurement

The relationships between resistance (degree of stopcock opening) and volumetric flow rate, as well as the

amount of water delivered within a specific period of time will be examined. In doing so, we’ll look into the

question of how long it takes to pump 2 litres of water into the upper tank with various degrees of opening

at stopcock V103.

Task

– Read the volumetric flow rate at the sight glass in the flow meter.

– Set volumetric flow rate to the required flow rate.

– Fill the upper tank.

– Measure the time it takes for the water level to rise from the 0.5 to the 2.5 litre mark.

– Enter measured time in the table.

Q [l/hr.] Time [s]

400

300

200

100

60

40

Volumetric flow rate per unit of time




Task

– Plot the measured time values and the volumetric flow rate settings on the graph.

– Describe your observations on the experiment in a few short sentences:

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

– How long would it take to pump 150 litres of water if the flow rate were set to 90 litres per hour?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________



– It takes 0.033 hours to fill the tank to the 2 litre mark. Calculate the volumetric flow rate for any desired

setting for stopcock V101 with the help of the measured time value. Check the selected volumetric flow

rate against the results of your calculation.

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________


2. Manual open-loop control

2.1 Project task: controlling water supply using hand valves

Water storage tank


Information

Water is pumped into a water tower from springs, rivers and lakes in order to supply households with

drinking water. Water is directed to domestic households from the tower. The upper tank will be filled with

water during the course of two experiments. There are two ways to fill a tank: either from above or below.

The influence of these two methods on the filling process needs to be examined.



2.1.2 Mechanical layout



Task

Modification according to the PI flow diagram

– Supplement the PI flow diagram with a second tank as shown in the photo on the preceding page.

– Set up the basic layout with two tanks according to the revised PI flow diagram.

M

P101

V102

PI103

FI101

V103

B101

V105




Work step Done

The basic setup with two tanks is required in order to conduct the experiments.



Inspect the piping connections.

Fill the lower tank with 3 litres of water.

Connect the system to the power supply units (24 V DC).

Experiment: fill the upper tank from below.

Close stopcocks V101 and V102, open stopcock V103 until the flow meter indicates 60 litres per hour.

Experiment: fill the upper tank from above.


Remove the 4 mm safety cable from the power supply unit and pull the mains plug.

After the experiment has been completed, the system is drained via stopcock V105.

2.1.4 Experiment: filling the upper tank from below

Task

– Close stopcock V103 until the volumetric flow rate is 60 litres per hour.

– Measure the time it takes to reach various fill levels as of 500 ml (first mark after the taper).

– Observe pump pressure at the pressure gauge.



Fill level [ml] Time [s] Fill level [ml] Time [s] Fill level [ml] Time [s]

600 1400 2200

700 1500 2300

800 1600 2400

900 1700 2500

1000 1800 2600

1100 1900 2700

1200 2000 2800

1300 2100 2900

Fill levels: filled from below

2.1.5 Experiment: filling the upper tank from above

Task


– Measure the time it takes to reach various fill levels as of 500 ml. Observe pump pressure at the

pressure gauge.


600 1400 2200

700 1500 2300

800 1600 2400

900 1700 2500

1000 1800 2600

1100 1900 2700

1200 2000 2800

1300 2100 2900

Fill levels: filled from above




Task

– Which fundamental influence does hydrostatic pressure have on pump performance?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

– Copy the measured values for filling from below and from above onto a diagram. Create a worksheet in

Excel with the measured values and the two line diagrams.

– However, filling from below takes longer than filling from above. What causes this?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________



– What effects can be observed at the surface of the water and with regard to turbulence during the two

filling processes?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

– Explain the relationship between the discharge rate and total head when an impeller pump is used.

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

– Calculate the pump’s total head. Refer to the data sheet on CD-ROM for technical data.

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________



2.2 Project task: controlling water supply using 2-way ball valve

Information

Process valves with pneumatic actuators are used more and more frequently in modern process engineering

because they offer a host of advantages compared with electric and hydraulic actuators. Pneumatic

actuators are easier to handle and they’re very sturdy and economical. They’re exceptionally well suited for

use in potentially explosive atmospheres. Please refer to Festo’s marketing manual, “ABC of Process

Automation”, for further information.

1: Pump 2: Water storage tower 3: End users

Operating principle


Information

When filling the upper tank, the volumetric flow rate can be changed by opening or closing stopcock V101 or

V103. The filling process and the control of the volumetric flow rate will now be partially automated by

means of a pneumatically actuated 2-way ball valve.

The upper tank is filled from above via the ball valve. Stopcock V102 for lower tank B101 is partially open

(20 %).



2.2.2 Mechanical layout, inspection

Task

– Close stopcock V105.

– The ball valve is installed parallel to stopcock V101 as a bypass. The valve is mounted onto the

rectangular profile and then connected to the piping system. The ball valve is opened and closed using

a pneumatic actuator. The regulating unit consists of a brass ball valve (2) with semi-rotary actuator (4),

a flange-mounted NAMUR valve (1) with solenoid coil (3) and a sensor box (5). The sensor box is used

for electro-mechanical position signalling to the control and regulating unit with visual display for the

user.

– Take into account addition information included in the data sheets on CD-ROM.

– Modify the piping layout so that the ball valve is correctly fitted.

– Check to make sure that all of the piping connectors are properly fitted.

– Check the piping connections to the impeller pump.

– Inspect the mechanical setup and create a test report (see CD-ROM).



2.2.3 Plans

Task

– Supplement the PI flow diagram for pneumatic control.

M

P101

V102

PI103

FI101

B102

V103

B101

V105

V101



Pneumatic circuit diagram

– Draw the pneumatic circuit diagram for the 5/2-way solenoid valve (1V1) with spring return and the

semi-rotary actuator (1A1).

– What requires special attention when connecting the three components, namely solenoid valve, semi-

rotary actuator and ball valve?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

Electro-pneumatic circuit diagrams

– Which possibilities exist for actuating the solenoid valve electrically?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________



– Draw circuit diagrams for the three possible means of actuation. Make a decision in favour of one

circuit. Mount the components onto the profile rail and wire the circuit. Explain your decision.

Variant 1 Variant 2

S5 “START” S6 “STOP”

Variant 3



2.2.4 Commissioning report

Task

The pneumatic components, the ball valve and the functions of all utilised mechanical and electrical

components such as switches, pushbuttons and impeller pump can now be commissioned and inspected.

The system is filled with water so that the pump is prevented from running dry. The water is pumped back to

the lower tank via the ball valve.

– Make a list of all of the characteristics and requirements for which the components have to be inspected

in the commissioning report. Tick the appropriate field after completing each inspection.



Electrical control switch and start and stop pushbuttons wired

Indicator light and pump wired, cable binders

Ball valve mounted to semi-rotary actuator and solenoid valve

Check pneumatic connection of the solenoid valve and the semi-rotary actuator

Connect the solenoid valve to the control switch/relay (variants 1 and 2).

Connect the solenoid valve to the pushbuttons (variant 3).


Switch the power supply unit on, the indicator light at the power supply unit lights

up.

Set control switch to “Pump on”, press the start pushbutton, the indicator light

switches on and the pump runs.

Variants 1 and 2: set control switch to “Open ball valve”, water flows into the tank.

Set control switch to “Close ball valve”, water stops flowing into the tank.

Variant 3: press “Open ball valve” pushbutton, water flows into the tank.

Press “Close ball valve” pushbutton, water stops flowing into the tank.

Press the stop pushbutton, the indicator light switches off and the pump stops

running.

Set control switch to “Pump off”, the indicator light goes out and the pump stops

running.

Inspector Date

Commissioning report



2.2.5 Experiment: filling using a pneumatically controlled 2-way ball valve

Task

– Fill the lower tank manually with 3 litres of fresh water.

– Connect the system to the power supply unit (24 V DC).

– Open the ball valve and stopcock V102 (approx. 20%). Switch the pump on.

– Control the filling process by opening and closing the ball valve. Decide on a specific fill level, for

example 2 litres, to which the upper tank should be filled. Switch the pump off upon when the fill level

has been reached and drain back down to 1 litre. Repeat the filling process.

– Determine the volumetric flow rate by measuring how long it takes to reach a fill level of 2 litres. Close

stopcock V102 to this end.

– Compare the filling process using the ball valve with the one using stopcock V101.


Task

– Which advantages does the semi-rotary actuator offer in comparison with adjustment by means of a

stopcock?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

– Which difficulties are experienced when trying to maintain a specific fill level?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________



2.3 Project task: electrical control of the pump in the water supply line


Information

Filling the water tower is closely associated with water being withdrawn by one or more households. This issue

can be clarified with the help of two experiments. In addition, control of the system should also be expanded

electrically. Wiring of the electrical components will be adapted in line with the task at hand.

The first experiment addresses the question of how the fill level of the upper tank can be kept constant

when varying amounts of water are withdrawn.

During the second experiment we’ll operate the pump with variable voltage values and clarify the

relationship between voltage, amperage and volumetric flow rate. Costs incurred during operation of the

system will also be ascertained.


The system will be operated using the basic setup with two tanks. There’s no need to remove the pneumatic

process actuator, although it’s not required for the experiment.

Work step Done






1st experiment: fill the upper tank from below.

Close stopcock V101, open stopcock V103 such that an initial flow rate of 60 litres per hour is indicated at

the flow meter.

2nd experiment: fill the tank using variable voltages for the pump.

Fill the upper tank from below, close stopcock V101, open stopcock V103 so that the flow meter indicates

60 litres per hour.





2.3.3 Relay circuit with pushbuttons

Information

The system will be expanded electrically. The detented switch will now serve as a mains switch. The

indicator light will still indicate the operating state.

The system will be started by pressing a green pushbutton and stopped by pressing a red pushbutton.

Briefly pressing the respective pushbutton is enough to start or stop the system.

Task

– Which type of circuit has to be set up when pushbuttons are used? Which additional component is

required?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

– Why do machines have to be controlled with a self-latching circuit instead of being operated with

switches?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________




Task

– The system has to be rewired for the following experiments. Draw the expanded circuit diagram with

two pushbuttons, a detented mains switch and an indicator light. Identify the components.

– Add the connecting cables to the image with the electrical components to indicate how they have to be

wired according to the circuit diagram.



2.3.5 Electrical wiring and setup plan

Task

– The system will need to be rewired for the following experiments. Assemble the electrical components.

They can be prewired before they’re mechanically attached to the profile. Proceed according to your

layout sketch and the setup plan you prepared in the “Planning” section of the chapter on “Plant

construction”. Base yourself on the circuit diagram with regard to wiring.

– Write down your assembly and wiring procedures. Fill out the following setup plan after you have

mounted and wired the components.


Electrical setup plan



2.3.6 Commissioning, electrical testing and report

Information

The new circuit with the pushbuttons and the functions of the existing electrical components, such as the

impeller pump, must now be started up and inspected. This is done by filling the system with water so that

the pump is prevented from running dry. The water is simply pumped around in a circular movement, i.e. out

of the bottom tank via the impeller pump and back into the lower tank from the upper tank.

Task

– Make a list of all the characteristics and requirements for which the electrical components have to be

inspected in the commissioning report. Tick the appropriate entry after completing each inspection.





Pump wired

Cables secured with cable binders



up.

Set control switch to “On”, press the start pushbutton, the indicator light switches

on and the pump runs.


running.



Set control switch to “Off”, the indicator light switches off and the pump stops

running.

Set control switch to “Off”, press the start pushbutton, the indicator light switches

off and the pump stops running.

Power supply unit “Off”, system is shut down

Inspector Date



2.3.7 Experiment: filling while simultaneously withdrawing water

The upper tank needs to be filled from below with a constant volumetric flow rate. Stopcock V101 is closed,

stopcock V103 simulates resistance in the system by being opened. It’s opened until the water flows into

the upper tank at a volumetric flow rate of 60 litres per hour. At the same time, the stopcock for discharge to

the user is open (approx. 20%).

– Measure the time it takes to fill the upper tank. Add the values to the table.


600 1400 2200 –

700 1500 2300 –

800 1600 2400 –

900 1700 2500 –

1000 1800 – 2600 –

1100 1900 – 2700 –

1200 2000 – 2800 –

1300 2100 – 2900 –

Filling with open discharge




Task

– Create a line diagram for fill level relative to time.

– What does the curve tell you?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

– What’s meant by the term self-latching circuit?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________



2.3.9 Experiment: pump start-up performance and power

The water level in the upper tank can be kept constant while water is withdrawn by changing the volumetric

flow rate. Volumetric flow rate will be influenced in this experiment by changing electrical voltage at the

power supply unit. You’ll need a power supply unit with variable output voltage for this experiment.

We’ll fill tank B102 with water from below. Stopcock V101 is closed. Stopcock V103 is opened to such an

extent that a volumetric flow rate of max. 400 litres per hour is achieved with 24 V DC. Stopcock V102 is only

partially opened (approx. 20%).

Task

– What are the volumetric flow rates when the pump is operated with various voltages ranging from 24 to

0 V DC?

– How does current consumption at the impeller pump change?

– Record the measured values and add them to the table.

Voltage U [V] Current I [A]

Electrical power P [W] = U · I

Volumetric flow rate Q [l/h]

Pressure pe [bar]

Hydraulic power P [W] = pe · Q

24

22

20

18

16

14

12

10

8

Filling using varying pump voltages




Task

– Draw a circuit diagram with a voltmeter and an ammeter.

– Create a diagram with two curves, one for volumetric flow rate Q and the other for electrical current I

relative to voltage U.

– What do the curves tell you about the pump’s start-up characteristics?

___________________________________________________________________________________________

___________________________________________________________________________________________



– What is the relationship between the three parameters current, voltage and volumetric flow rate?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

– Calculate electrical and hydraulic power, as well as efficiency, for a volumetric flow rate of 200 litres per

hour.

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

– What is the relationship between the impeller pump’s current consumption and its output performance?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

– How high are the electrical power costs when the pump is operated 8 hours a day for one month (30 days)

with a volumetric flow rate Q of 200 litres per hour? The cost of electrical power is roughly €0.17 per kWh.

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________


3. Manual closed-loop control

3.1 From a control loop system to a control circuit

Information

Our fill-level system includes open and closed-loop control processes. How they differ will become clear

when we consider their respective characteristics.

Every process has an input quantity and an output quantity. For example, if we switch on the power supply

unit which supplies electrical power to the impeller pump, electrical current (input quantity) flows and the

pump begins to rotate and deliver water (output quantity). The input quantity affects the output quantity.

Open-loop control

However, if the output quantity is not fed back to the input as a signal so that, for example, the power

supply unit is switched off when the tank is full, we speak of an open-loop control process. In the case of

open-loop control, a process is started and stopped without periodically comparing and changing the

variables to be controlled.

Closed-loop control

If we want to regulate the filling process with a closed-loop control process, we need to continuously record

the fill level, for example via observation or a sensor and continuously compare the current fill level (actual

value) with the desired fill level (target value). Whenever deviation from the target value is detected, an

attempt is made to match the controlled variable (actual value) to the reference variable (target value) by

means of appropriate control measures. This type of control has a closed control path, also known as control

circuit.

Comparison of a human being as a controller and automated control using fill level monitoring as an

example:

Human being as a controller Automated control

Specified value Setpoints

Observation Actual value detection (ultrasonic sensor)

Make note of value Archive

Open or close valve manually Transmit electrical manipulated variable to valve or pump

Regulator optimisation



Basic terminology for closed-loop control technology

Controlled variable x

The quantity to be controlled is designated controlled variable x. In our example this is the fill level or the

volumetric flow rate.

Manipulated variable y

Automated closed-loop control is only possible if the system can be manipulated and the controlled variable

influenced. The extent to which the controlled variable can be influenced is manipulated variable y. In the

case of closed-loop control of a fill level, the manipulated variable is the degree to which the stopcock is

opened, and in the case of closed-loop control of the volumetric flow rate, it’s electrical current at the pump.

Reference variable w

Reference variable w is also known as the controlled variable setpoint. It specifies the desired value of the

controlled variable. The reference variable may remain constant over time, but it may also change. The real

value of the controlled variable is called the actual value.

Disturbance variable z

All controlled systems are subject to disturbance. These are often the only reason that closed-loop control is

necessary at all. In our example, the stopcock for discharge to the consumer is opened and the fill level

changes or the valve setting for filling the upper tank is changed which results in a change to the volumetric

flow rate. These interfering influences are designated disturbance variable z.

The controlled system is the part of the overall setup within which the controlled variable must be matched

with the value of the reference variable. The controlled system can be represented as a system with the

controlled variable as the output quantity and the manipulated variable as the input quantity.

System deviation xd

The difference between the reference variable and the controlled variable is called system deviation xd or e.

This difference is calculated as follows: e = w - x

Closed-loop controller

It is the task of the closed-loop controller to keep the controlled variable as close as possible to the

reference variable. The value of the controlled variable is continuously compared with the reference variable

by the closed-loop controller. The value of the manipulated variable is calculated on the basis of this

comparison, as well as control response, and is read out.

Controlled variable xActual value

Manipulated variable ySystem deviation xd

Reference variable wSetpoint

( )Control responseAlgorithm

+

Basic function of a regulator



Control circuit

The control circuit contains all the components of the closed loop that are required for automated closed-

loop control.

Controlled system

Controlled variable xActual value( )

Controller Reference variable wSetpoint( )


Block diagram of a control circuit

Controlled system

The controlled system is the part of the machine or system within which the controlled variable is to be

matched to the specified value and the disturbance variables are offset by the manipulated variables. The

manipulated variable is not the controlled system’s only input quantity; interfering influences also occur as

input variables.

In order to select a closed-loop controller for a controlled system, the performance of the controlled system

must first be known. The control technician is not interested in the technical sequences which take place

within the controlled system, but only in system performance.

3.2 Project task: controlling the fill level in the tanks


In the case of water supply, households withdraw various quantities of water. Two experiments will be used

to clarify how a specified fill level can be constantly maintained in the upper tank. Closed-loop control is

possible in different ways:

· Open and close stopcock V101 or V103.

· Switch the pump on and off.

· Change voltage supplied to the pump.

During the first experiment, “manually keeping the fill level constant in the upper tank”, we’ll attempt to

regulate the fill level by switching the pump on and off. We can supply the pump with voltages ranging from

0 to 24 V using the power supply unit. The pump is switched on and off with the pushbuttons. Observe the

control process.

During the second experiment, “controlling the fill level using an analogue controlled pump”, we’ll operate

the pump with variable voltage ranging from 0 to 24 V DC, and thus control the volumetric flow rate and

influence the tank’s fill level within a certain period of time. You’ll need a power supply unit with adjustable

output voltage to this end.




Task


– Check to make sure that all piping connections are correct.

– Check to make sure that all electrical wiring connections are correct.

– Fill the lower tank with 3 litres of water.

– Connect the system to the respective power supply unit (max. 24 V DC).

– Carry out the experiment.

– Remove the 4 mm safety cable from the power supply unit and pull the mains plug.

– After the experiment has been completed, the system is drained via stopcock V105.

3.2.3 Experiment: manually keeping the fill level constant in the upper tank

The upper tank should always have a constant level of water of 2000 ml. Varying quantities of water are

withdrawn via stopcock V102 and supplied to a household (lower tank B101).

Task

– Switch the pump on and off with the pushbutton so that the fill level remains constant.




Task

Enter the following control technology terms to the block diagram of the system: actual value x, setpoint w,

manipulated variable y, switching difference sd, disturbance variable z, closed-loop controller, controlled

system.

M

P101

V102

PI103

FI101

V103

B101

V105

V101

Reference variable wSetpoint, fill-level

Controlled variable xActual value, fill-level

Manipulated variable yVoltage

( )

( )

( )

– A fill level of 2100 ml is established as an upper limit and 1900 ml is the lower limit. This results in a

switching difference sd of 200 ml. Why are these limit values specified?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________



– Establish the inequality for switching the pump on and off. Inequality is meant here as the “greater” or

“smaller” relation amongst the actual value, the setpoint and the switching difference.

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

– Represent the filling process graphically as a line diagram. Plot the fill level on the ordinate (Y-axis) and

time on the abscissa (X-axis).

– What do we call this type of control? In which types of devices do closed-loop controllers operate on the

basis of this principle? Provide several examples.

___________________________________________________________________________________________

___________________________________________________________________________________________

– Which features characterise this type of control?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________



3.2.5 Experiment: controlling the fill level using an analogue controlled pump

Once again, the tank should be filled to a constant level of water of 2000 ml. Varying quantities of water are

withdrawn via stopcock V102 and supplied to a household (lower tank B101). The volumetric flow rate is

influenced by changing speed, thus enabling the system to react to irregular withdrawals of fresh water from

upper tank B102.

– Vary the pump speed by increasing and decreasing voltage supplied by the power supply unit and

observe the volumetric flow rate.


Task

– Allocate the terms and characteristics from the description of the experiment to the control technology

terms.

Controlled variable: ____________________________ Manipulated variable: __________________________

Reference variable: _____________________________ Disturbance variable: ___________________________

– First of all, fill the upper tank from above with stopcock V102 fully closed. Then open stopcock V102

according to the specifications in the table and describe what you observe while controlling the process.

React to changes in the fill level by varying the power output voltage.

Stopcock V102 Control process, observations

Closed

10% open

50% open

100% open

Test report

– Why is this also known as continuous control?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________



– Create a graphic representation of the closed-loop control process. Draw a graph which shows the fill

level over a period of time as a strictly qualitative characteristic.

3.2.7 Experiment: pressure and flow control

Separately conduct pressure control and flow rate control, also known as volumetric flow rate control. Control

pressure and volumetric flow rate by varying the output voltage of the power supply unit between 0 and 24 V DC.

Set up the circuit according to the PI flow diagrams.

Pressure control

M

P101

PI103

V103

B101

V105



Flow rate control

M

P101

V103

B101

V105

FI101


Task

– Determine the manipulated variable required for maintaining constant pressure, as well as for

maintaining constant volumetric flow rate, with varying resistance (stopcock V103).

Target pressure (w) = 200 mbar

Target volumetric flow rate (w) = 100 l/hr.

– Add the voltage values for the various stopcock settings to the table. Conduct the experiment once with

constant pressure and once with constant volumetric flow rate.

– Mark the opening values of the stop cock on the rotary cap so that the experiment can be duplicated

exactly.

Setting for stopcock V103

Pressure control, voltage U (y) where pe = 200 mbar (w)

Flow rate control, voltage U (y) where Q = 100 l/hr. (w)

Open

20% closed

40% closed

60% closed

40% closed

20% closed

Values table



– What is the relationship between the stopcock setting and pressure or volumetric flow rate?

Constant pressure:

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

Constant volumetric flow rate:

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________


4. Evaluation of learning objectives for manual measurement, open-loop and closed-loop control

1. How do pressure and volumetric flow rate of a liquid respond when resistance is increased in the inlet

line which feeds the tank?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

2. 70 litres of water have to be recirculated using a volumetric flow rate of 200 litres per hour. How long

does the pump have to work?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

3. Which physical quantities determine hydrostatic pressure?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

4. Why does it take longer to fill the upper tank in our system from above than from below?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________



5. The filling nozzle at the top can be fitted at a level of, for example, 1.1 metres. How much pump

pressure would be required to reach this filling height?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

6. Describe how a self-latching circuit functions. Which components are required for such a circuit?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

7. The upper tank is continuously filled with water and a certain amount of water is discharged from the

tank. In a diagram, the process would be designated asymptotic, i.e. it approaches a specific value.

Sketch a graph which shows the fill level over a period of time as a qualitative characteristic.



8. Describe in your own words the procedures used for connecting an ammeter and a voltmeter in order to

record pump values.

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

9. You’re working with variable voltage within a range of 0 to 24 V. How do volumetric flow rate and

amperage I change when voltage is reduced from 24 to 0 V.

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

10. The maximum pump efficiency is h = 0.26. What is the meaning of this value with regard to our

experimental system and which effects does efficiency have in actual practice?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

11. Sketch a pneumatically actuated 5/2-way valve with spring return.

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________



12. Which fundamental advantages are offered by a 2-way ball valve with electro-pneumatically actuated

actuator as opposed to manual operation?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

13. Describe the terms “open-loop control” and “closed-loop control” using a radiant heater as an example.

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

14. How are manipulated variable y and controlled variable x related?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

15. How does a two-step controller work?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

16. Why is an excessively small switching difference disadvantageous?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________



17. What’s the fastest way to get the system adjusted to the setpoint?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

18. What is the control process called with which the manipulated variable can be continuously varied?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

19. Pressure needs to be kept constant within the fill-level system, even when the volumetric flow rate is

continuously increased. Which parameter must be changed within the system?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

20. How can the volumetric flow rate within the fill-level system be kept constant, even though the pump

needs to be operated in an energy-saving fashion?

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

© Festo Didactic GmbH & Co. KG C-1


1. Basic principles ___________________________________________________________________ C-3

1.1 Computer-aided control technology ___________________________________________________ C-3

1.2 System conversion for automated measurement and control ______________________________ C-5

2. Automated measurement __________________________________________________________ C-13

2.1 Project task: bath recirculation ______________________________________________________ C-13

2.1.1 Task description __________________________________________________________________ C-13

2.1.2 Setting up the system, inspection ____________________________________________________ C-16

2.1.3 Experiment: operating the pump with variable voltage values ____________________________ C-17

2.2 Project task: pressure measurement during recirculation ________________________________ C-17



2.2.3 Experiment: pressure measurement using a pressure sensor _____________________________ C-20

2.3 Project task: flow measurement _____________________________________________________ C-20



2.3.3 Experiment: flow measurement using a flow sensor _____________________________________ C-21

2.4 Project task: determine the fill level of the upper tank ___________________________________ C-21



2.4.3 Experiment: measuring the fill level using an ultrasonic sensor ___________________________ C-23

3. Automated open-loop control _______________________________________________________ C-25

3.1 Project task: filling process _________________________________________________________ C-25



3.1.3 Experiment: metered filling via the pneumatic actuator __________________________________ C-26

3.2 Project task: filtering process in a galvanising plant _____________________________________ C-26



3.2.3 Experiment: determining pressure and volumetric flow rate ______________________________ C-29

3.2.4 Experiment: creating a characteristic pump curve _______________________________________ C-30

3.3 Project task: water supply __________________________________________________________ C-33



3.3.3 Experiment: filling the tank from below using the pump _________________________________ C-34

3.3.4 Experiment: filling the tank from above using the pump _________________________________ C-35

3.3.5 Experiment: filling the tank from above while simultaneously withdrawing water ____________ C-36

3.4 Project task: dosing an amount of liquid ______________________________________________ C-37


3.4.2 Experiment: dosing an amount of liquid _______________________________________________ C-38


C-2 © Festo Didactic GmbH & Co. KG

4. Automated closed-loop control _____________________________________________________ C-41

4.1 Project task: controlling the fill level using a two-step controller __________________________ C-43



4.1.4 Commissioning ___________________________________________________________________ C-45

4.1.5 Experiment: controlling the fill level using a two-step controller ___________________________ C-45

4.2 Project task: controlling the fill level using a continuous controller ________________________ C-49


4.2.2 Experiment: controlling the fill level with a continuous controller __________________________ C-50

4.2.3 Experiment: controlling the fill level using a proportional controller ________________________ C-51

4.2.4 Experiment: controlling the fill level using an integral controller ___________________________ C-52

4.2.5 Experiment: controlling the fill level using a proportional-integral controller

(parallel P and I components) _______________________________________________________ C-54

4.3 Project task: refrigerating plant ______________________________________________________ C-56



4.3.3 Commissioning report _____________________________________________________________ C-57

4.3.4 Experiment: flow control using a proportional-integral controller __________________________ C-57


and closed-loop control ____________________________________________________________ C-59


1. Basic principles

1.1 Computer-aided control technology

Information

This is an introduction to automated control technology and is based on the knowledge of manual control

that has already been acquired. You’ll learn the basics of computer aided control with the help of practical

examples.

Every control circuit consists of a controlled system and a controller.

1 Setpoint specification

2 System deviation = setpoint - actual value

System deviation is calculated by means of a control function and is transmitted to the controlled system as a manipulated

variable

(3). The control function is generally processed with the help of software.

3 Manipulated variable

4 The manipulated variable must be boosted so that the actuator’s final control element receives a signal with which it can work.

5 The controlled system (e.g. fill level) is changed by means of the manipulated variable.

6 The controlled system’s actual value is measured and fed back to point 2.

In most cases, the actual value must be electronically converted.

Software solutions for a controller in a PC or a PLC work in a cyclical fashion, i.e. points 2 through 6 are run continuously.

1. Basic principles


Examples of controlled systems:

– Maintain a constant fill level in a tank

– Change and maintain temperature in a room

– Keep motor speed at a specified value

– Travel accurately to an axis position

– Maintain constant pressure in a piping system

Types of controllers:

· Discontinuous controller

These controllers are characterised by the fact that their manipulated variables are only capable of

changing between the on and off states, i.e. two-step controller.

· Continuous controller

With continuous controllers, the manipulated variable is infinitely adjustable, e.g. PID controller.

In conventional control technology, a difference is made between the following controllers according to how

the manipulated variable is determined (simplified excerpt).

Controller Graphic symbol Determination of the manipulated variable via the control function

2-step controller

The manipulated variable is compared with an upper and a lower limit

value.

P controller

System deviation is influenced by means of a factor.

I controller

The sum of all system deviations is influenced by means of a factor.

PI controller

The characteristics of the P-controller and the I-controller are combined.

PID controller

The manipulated variable is determined by the

D parameter based on the time factor by which system deviation is

changed.

1. Basic principles


Technical learning objectives

Participants will:

· Learn to convert electrical actuation to actuation with a PC

· Become familiar with how to set up and adjust sensor signals

· Become familiar with practical PC measurement technology

· Learn to differentiate between various types of controllers and control circuit performance

· Learn to use continuous and discontinuous control for automated measurement, open-loop and closed-

loop control

· Become familiar with using a PC as a control and regulating device in combination with FluidLab® PA

software

1.2 System conversion for automated measurement and control

Information

The system is, as in the section on “manual measurement, open-loop and closed-loop control”, equipped

with a control panel used for manual measurement, open-loop and closed-loop control. The system must

now be modified so that signals can be transmitted via the EasyPort PC interface. The depicted control panel

is not used for automated measurement and control.

1. Basic principles


The basic setup for automated measurement, open-loop and closed-loop control will be demonstrated using

pump control as an example:

Item 1 2 3

Digital pump control , on/off PC transmits Bit3 to

EasyPort.

EasyPort generates a voltage

signal (relay) of 0 V or 24 V.

Motor runs at nominal power

with 24 V.

Analogue control PC transmits a decimal value

(e.g. double word) which

corresponds to a voltage

within a range of 0 to 10 V.

EasyPort generates a control

signal of 0 to 10 V.

The motor controller boosts the

signal to within a range of 0 to 24

V. The motor runs at an infinitely

adjustable speed.

1. Basic principles


Task

The system will be equipped with a preassembled I/O board. Carry out conversion as described in the

following steps:

1. Switch off supply power.

2. Unplug the laboratory cable via with safety valve socket.

3. Unplug the pump motor.

4. Mechanical removal of the control panel from the rectangular profile

System with control panel System without control panel

1. Basic principles


5. Screw the preassembled I/O boards to the rectangular profile.

Important modules are required for operation via a PLC or via a PC and EasyPort, in order to process

measured values and control the actuator.

Assembly Figure Description

F-U converter for flow sensor

Depending on the flow rate, the flow sensor generates a

pulse frequency within a range of 40 to 1200 Hz. This

pulse frequency is converted to a voltage value within a

range of 1 to 10 V by the F-U converter.

Motor controller

The analogue manipulated variable of 0 to 10 V from the

EasyPort or a PLC is boosted to 0 to 24 V and an

appropriate amperage by the motor controller. Amperage

must be limited in order to ensure safe operation.

Modules on the I/O board

Further information is included in the data sheets on the CD-ROM.

1. Basic principles


6. Connect the EasyPort to the I/O board with a SysLink cable.

7. Connect the EasyPort to the PC (USB or serial cable).

8. Connect a 24 V power supply unit.

9. Connect the outputs for analogue and binary signals between the I/O board and the EasyPort.

1. Basic principles


10. Install the software.

– Install the EasyPort driver from the EasyPort CD-ROM.

– Install FluidLab® PA.

11. Test the system.

– Supply EasyPort with power.

– Start FluidLab® PA software.

Note

After starting the software, a message indicates whether or not a connection has been successfully

established. If this is not the case, check all connections within the system. Otherwise, exit the software

and disconnect the USB plug. Reinsert the USB plug after 5 seconds. Start the software again.

12. Select the “Setup” menu.

The outputs can be activated with the sliders in the user interface.

1. Basic principles


13. Assignment of inputs and outputs on the I/O board:

Name Device Abbreviation Note

Digital output 0 2-way ball valve with pneumatic

actuation

A0 Spring return

Digital output 2 Changeover relay A2 Relay = 0: pump is binary controlled

Relay = 1: pump is analogue controlled

(0 to 10 V)

Digital output 3 Pump A3

Analogue output 0 Pump AOUT 1

Analogue input 0 Fill level (ultrasonic) AIN 0

Analogue input 1 Flow sensor AIN 1

Analogue input 2 Pressure sensor AIN 2

1: I/O terminal 2: Analogue terminal 3: Relay 4: Motor controller

5: Measuring transducer 6: Starting current limiter 7: Motor clamp 8: H-rail

Complete layout plan

1. Basic principles



2. Automated measurement



Depending on the setup, water can be transferred to lower tank B101 or pumped into upper tank B102 with

the pump.

The pump can be operated by switching 24 V supply power on or off (output 3). Alternatively, it can be

variably supplied with control voltage within a range of 0 to 10 V (analogue output 0). The control signal is

boosted by means of a motor controller.

The type of control used (on/off or analogue) is selected with a changeover relay (output2).



Task

The pump will be connected and tested during the following experiment. Simply pumping water into lower

tank B101 is sufficient for this function test.

– Set up the fill-level system with one tank as specified in section 1.1.1, part A.

– Base yourself on the PI flow diagram.

– Before commissioning, make sure all the project kit’s modules and piping function correctly and do not

leak.

– Replace any damaged parts.

M

P101

V102

PI103

FI101

B102

V103

B101

V105

V101




– Plug the pump into the I/O board. The allocations are included in the circuit diagram on the CD-ROM.

– Set up the water circuit (see flow diagram).

Note

The pipe connection to tank B102 must be interrupted or equipped with a closed stopcock. Close V101

and V105, open V102 and V103.

– Fill B101 approximately half full with water.

– Connect the 24 V power supply unit to mains power.

– Switch the power supply unit on.

– Start the software (FluidLab® PA).

– Open the “Setup” menu in the software and operate the system using the buttons (see below).



2.1.3 Experiment: operating the pump with variable voltage values

– Select each of the values listed below and document your observations.

No. Digital outputs Analogue outputs (set at sliders)

Pump (observe)

1 A3 = on A2 = off 0 V

2 A3 = on A2 = on 0 V

3 A3 = off A2 = on 4 V

4 A3 = off A2 = on 8 V

5 A3 = off A2 = on 10 V

2.2 Project task: pressure measurement during recirculation


Pressure plays a significant role in fluid systems. In practice pressure changes due to reactions which occur

in mixtures, during filtration or recirculation, and must be continuously recorded and documented. In order

to be able to read out the value with the help of a PC, the pressure gauge with indicator is replaced by a

pressure sensor. As a rule, pressure sensors require 24 V DC supply power and generate an analogue

voltage signal within a range of 0 to 10 V, which is proportional to pressure.

The purpose of the pressure sensor is to measure liquid pressure directly downstream of the pump. According to

the data sheet, the sensor reads out a voltage of 0 to 10 V within a pressure range of 0 to 400 mbar.




– Switch the system off and pull the mains plug.

– Drain the water via stopcock V105.

– Install the pressure sensor downstream of the pump.

– Electrically connect the pressure sensor in accordance with the circuit diagram (CD-ROM).

– Valve settings: V101 and V105 closed, V102 and V103 open, remove piping to tank 102, insert a

blanking plug into the end of the pipe or install a stopcock in the bottom inlet and close it.

– Fill with water.

– Set up the software.

– Set the pressure value at the PC after opening the “Setup” menu:

– Determine factor and offset: calculate the physical display value:

Physical value = sensor voltage · factor + offset

If values are to be displayed in bar, the factor is calculated as follows:

The following data are specified for the sensor: a pressure range of 0 to 0.4 bar and a voltage range of

0 to 10 V.

04.0V0V10

bar4.0Factor =

-=



Default setting for the pressure duct: factor = 0.04 and offset = 0.0 (see figure)

1 Voltage read out by the sensor 2 Factor 3 Offset

4 The signal can be filtered (attenuated). The higher the number, the greater the attenuation.

In order to ensure correct representation of the scales in the diagrams, it’s important to always enter the

maximum physical value and the appropriate unit of measure (see the two right-hand columns in the

screenshot).

Task

At a pressure of 0 to 10 bar, the pressure sensor reads out a voltage within a range of 2 to 10 V.

– Calculate factor and offset.

=·-=

=-

=

voltage InitialFactorOffset

voltage Initialvoltage Finalvalue Final

Factor



2.2.3 Experiment: pressure measurement using a pressure sensor

– Operate the pump with the three following voltage values and make a note of what you observe at the

software pressure display.


Pressure display (observe)

1 A3 = on A2 = off 0 V

2 A3 = off A2 = on 5 V

3 A3 = off A2 = on 10 V

2.3 Project task: flow measurement


The purpose of the flow sensor is to measure the pump’s volumetric flow rate. Liquid flows through the

measuring transducer and causes a vane to rotate. The vane is equipped with an inductive sensor which

generates pulses. The pulses are converted into a voltage which is proportional to the volumetric flow rate

by an F/U converter. At a volumetric flow rate of 0 to 7.5 litres per minute, the flow sensor generates a

voltage signal within a range of 0 to 10 V.




– Install the flow sensor downstream of the pump.

– Connect the flow sensor electrically according to the circuit diagram (see CD-ROM).


– Start the software and open the “Setup” menu.

– Set factor and offset: the physical display value is calculated as follows:


Flow rate display in litres per minute, factor = 0.75, offset = 0



2.3.3 Experiment: flow measurement using a flow sensor

– Change the pump speed again by setting supply voltage to three different settings and make a note of

what you observe at the flow rate display in the software.


Flow rate display (observe)

1 A3 = on A2 = off 0 V

2 A3 = off A2 = on 5 V

3 A3 = off A2 = on 10 V

2.4 Project task: determine the fill level of the upper tank


The ultrasonic sensor measures distance and can be used to detect fill levels. The ultrasonic waves are

refracted at the surface of the water and returned to the sensor. At a distance of 50 to 270 mm from the

water, the sensor reads out a voltage within a range of 0 to 10 V. The ultrasonic sensor is attached to the

inside of the lid of tank B102, from where it measures the fill level.




M

P101

V102

PI103

FI101

B102

V103

B101

V105

V101

LIC102

– Mount upper tank B102 and lay piping for the system in accordance with the PI flow diagram.

– Mount the ultrasonic sensor onto the upper tank.

– Electrically connect the ultrasonic sensor in accordance with the circuit diagram (CD-ROM).

– Set the valves so that liquid can be pumped into the upper tank: V101 open, V103 open , V102 approx.

5% open.


– Set factor and offset

The physical display value is calculated as follows:




Depending on which physical quantity is to be displayed, factor and offset are entered as follows:

The following applies in the case of a sensor signal within a range of 0 to 3 litres and a voltage of 0 to 10 V:

Fill level in litres Factor = 0.27 Offset = 0.0

Fill level in mm Factor = 22 Offset = 0.0

Note

The sensor signal lies within a range of 0 and 2.7 l, which corresponds to 0 to 10 V. Due to the fact that

the bottom of the tank is conical, measurement begins as of the cylindrical portion of the tank and

roughly the first 0.5 l are disregarded in this example.

2.4.3 Experiment: measuring the fill level using an ultrasonic sensor

– Fill upper tank B102 according to the entries in the table and document your observations.

– Complete the table.

No. Digital outputs Tank B102, fill level

sensor (litres) Observation

1 A3 = off A2 = off Empty =

2 A3 = on A2 = off

Approx. 50% full =

100% full =

3 A3 = off A2 = off


3. Automated open-loop control

3.1 Project task: filling process


The automated filling process will be demonstrated with the help of the 2-way ball valve with pneumatic

actuation. The ball valve is installed between the upper and the lower tank. Information on operating the 2-

way ball valve can be found in section 2.2, part B, and in the data sheet (CD-ROM).

– Set the system up according to the PI flow diagram.

M

P101

V102

PIS+103

FIS+101

B102

V103

B101

V105

V107

LA+111

V112

V101

LS–114

LS–113






– Connect 2-way ball valve V102 according to the circuit diagram (CD-ROM).

– Complete tubing connections for pneumatic actuation (semi-rotary actuator) of the 2-way ball valve (at

least 5 bar compressed air).

– Fill the lower tank with water.

3.1.3 Experiment: metered filling via the pneumatic actuator

– Carry out the experiment as indicated in the table and document your observations.

No. Digital outputs Step Observation

1 A3 = on A0 = off Pump water into B102.

2 A3 = off A0 = off –

3 A3 = off A0 = on Water flows through V102.

3.2 Project task: filtering process in a galvanising plant


The acid bath at a galvanising plant has to be continuously recirculated and filtered. As contamination in the

acid bath increases, resistance upstream of the filter increases and circulating pressure rises. When a

specified pressure is exceeded, the filter must be cleaned or replaced. The cross section in the valve is

reduced with hand valve V103. This corresponds to a clogged filter in actual practice. We are thus able to

simulate filter contamination with hand valve V103.

The experiment is intended to demonstrate the relationship between resistance (filter contamination) and

pressure in the piping system.

The pump is controlled via the PC and pressure is measured with a pressure sensor. The characteristic

pressure curve is recorded in a time diagram.




– First, modify the system according to the PI flow diagram or the figure. A setup including one tank, the

pressure sensor and the flow sensor is required.

– Double check the piping layout and the electrical connections before commissioning.

– Test the pump, the pressure sensor and the flow sensor for correct functioning.

– Fill tank B101 with 2 to 2½ litres of water.

M

P101

PI103

FI101

V103

B101

V105

V102

P101

B101

FI101

PI103



Task

– Connect the EasyPort, start the software and select the settings menu.

– Enter and double-check factor and offset settings for the sensors.

– Enter the corresponding values in the table.

Setting checked Comment

Sensor settings Pressure bar Factor = 0.04 Offset = 0

or pressure kPa Factor = 4 Offset = 0

or pressure PSI Factor = 5.8016 Offset = 0

Volumetric flow

rate

l/min. Factor = 0.75 Offset = 0

Valve settings V101

V102

V103

– Create a commissioning report for the system.

Characteristic, requirement for component Fulfilled Failed, comments

Piping assembled and leak-proof

Pressure sensor installed

Flow sensor installed

Electrical wiring and connecting cables connected

Lower tank filled with 2 to 2½ litres of water

Software installed, sensor values adjusted

Test pump on/off with PC

Test the signal from the pressure sensor

Test the signal from the flow sensor



3.2.3 Experiment: determining pressure and volumetric flow rate

– Measure pressure and volumetric flow rate with changing line resistance.

– Carry out the steps specified in the table and document your observations.

Menu: Control and measure

No. Task Data from the diagram Note/observation

1 Pump on, A3 = on

Hand valve open completely

Pressure =

Volumetric flow rate =

2 Slowly close hand valve V103

3 Hand valve V103 closed Pressure =

Volumetric flow rate = 0 l/min.

4 Slowly open hand valve V103

1 Volumetric flow rate 2 Pressure

Diagram of the sensor signal while closing hand valve V103



Task

– What is the relationship between the pipe’s cross section, volumetric flow rate and pressure?

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– Why is volumetric flow rate reduced with a smaller cross section?

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– How would a significantly longer piping network influence the system?

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3.2.4 Experiment: creating a characteristic pump curve

In this section volumetric flow rate with changing line resistance and analogue pump control will be

examined. The pump can be operated with a control voltage within a range of 0 to 10 V with the help of a

motor amplifier. Control must also be switched on and off with the help of a relay.

1: Set changeover relay to 1 2: Preset voltage to 0 to 10 V

Sample settings in the settings menu



Menu: Select characteristic U-Q curve

– Carry out the experiments described below, document your observations in the table and create a

characteristic curve.

No. Task Data Note/observation

1 Increase voltage at the pump from 0 to

10 V, and then decrease it back to 0 V

again.

Voltage [V] Volumetric

flow rate

[l/min.]

2

2 Hand valve open all the way 4

3 Take values from the diagram 6

8

10

1 Voltage is increased from 0 to 10 V. 2 Voltage is decreased from 10 to 0 V.

Sample characteristic U-Q curve



Task

– How does the pump respond to rising control voltage?

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– What is the effect of varying the speed at which control voltage is changed?

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– What does hysteresis mean?

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3.3 Project task: water supply


Water is pumped into a water tower from springs, rivers and lakes in order to supply households with water.

Water is directed to domestic households from the tower. The upper tank will be filled with water during two

experiments. There are several different ways to fill the tank:

· The fill pipe enters the upper tank from below.

· The fill pipe enters the upper tank from above.

· The fill pipe enters the upper tank from above while water is simultaneously being withdrawn from

below.

M

P101

PIS+103

FIS+101

B102

V103

B101

V105

V107

LA+111

V112

B102

V103V107

LA+111

V112V102

V101

LS–114

LS–113

V101

LS–114


– Set the system up with two tanks as shown in the flow diagram. Connect and test the pump and the

ultrasonic sensor.

– Base yourself on section 2.4 during setup.

– Double-check the piping layout and the electrical connections.



3.3.3 Experiment: filling the tank from below using the pump


No. Task Done Observations

1 V101 closed

V107 closed

V103 open

V102 closed (A0 = off)

V112 closed

2 Fill B101 with 3 litres of water.

3 Open the “Control and measure” menu

in the software.

Pump A3 = on

4 After roughly 40% filling

Pump A3 = off

5 V102 open (A0 = on)

V112 open

Characteristic curve for filling from below



3.3.4 Experiment: filling the tank from above using the pump



1 V101 open

V107 open

V103 closed


V112 closed (while filling)

2 Fill B101 with 3 litres of water


in the software, pump A3 = on


Pump A3 = off

5 V102 open (A0 = on)

V112 open

Characteristic curve for filling from above



3.3.5 Experiment: filling the tank from above while simultaneously withdrawing water



1 V101 open

V107 open

V103 closed

V102 open (A0 = on)

V112 20% open

!



in the software, pump A3 = on


Pump A3 = off

5 V102 closed (A0 = off)

Characteristic curve for filling from above while simultaneously withdrawing water



Task

– Why is the surface of the water less turbulent when the tank is filled from below?

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– How could reverse flow through impeller pumps be prevented?

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– Why does the fill level rise more slowly when water is withdrawn simultaneously?

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3.4 Project task: dosing an amount of liquid


A certain amount of water must be fed to a mixture of solids in a cement mixer. The quantity is time-

controlled. A constant volumetric flow rate must be maintained as a prerequisite, for example 2 litres per

minute. The pump is controlled via a PC. The analogue output is used as the manipulated variable.

Volumetric flow is measured with a volumetric flow rate sensor. The characteristic curve is recorded in a

time diagram. One litre of water should be added to the mixture.

Task

– Set the system up with one tank in accordance with the PI flow diagram.

– Connect and test the pump, the pressure sensor and the flow sensor.

– Double-check the piping layout and the electrical connections before commissioning.



3.4.2 Experiment: dosing an amount of liquid

– Connect the EasyPort to the PC and start the software.

– Enter the appropriate settings in the settings menu.

P101

FI101

V103

B101

V105

V102

1: Activate the changeover relay 2: Adjust control voltage



– Carry out the work steps described below and record your observations in the table.

No. Work step Setting checked

Comment

1 Volumetric flow

rate sensor

Volumetric flow

rate

l/min Factor = _______

Offset = 0

2 Valve settings V101

V102

V103

3 Set to analogue

mode

A2 = on

4 Adjust

manipulated

variable

Volumetric flow rate

Q = 2 l/min.

Control voltage

U = = _______ V

Increase the

manipulated variable

until Q = 2 l/min.

5 Pump off A3 = off

A2 = off

6 Switch pump on

for 30 seconds

A3 = off

A2 = on

Control voltage

U = = _______ V

Measure with

stopwatch or read from

the diagram

7 Evaluate the

diagram.

Values from the diagram:

Volumetric flow rate Q = ___________ l/min.

Time t = ____________ sec.

Calculated water quantity over time: Q · t = ________



Sample solution for dosing procedure

Task

– Why isn’t the amount of water exactly correct?

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– How long does the pump have to run (Q = 2 l/min.) in order to deliver 0.5 litres of water?

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4. Automated closed-loop control

Information

A control circuit always consists of a control device (closed-loop controller) and a device to be regulated

(controlled system), for example a fill-level system.

Schematic diagram of a regulating system

Description

The task of the closed-loop controller (control function) is to control the controlled system so that it remains

at setpoint w. Actual value x is continuously measured and compared with setpoint w to this end. The

regulator calculates manipulated variable y. The manipulated variable influences the process via a final

control element.

Knowledge of the characteristics of the controlled system is essential for selecting and adjusting the

regulator. Characteristics of controlled systems are usually determined during a test run.

Discontinuous and continuous controllers:

The actual value is measured using analogue sensors for both types of controllers. In the case of

“discontinuous controllers”, the manipulated variable has only two states (on/off). In the case of “continuous

controllers”, the manipulated variable is displayed in an infinitely adjustable fashion (e.g. 0 to 10 V).

The characteristics of the controlled system, “tank B102”, will be observed as described below. The tank will

be filled from above via a piping system.



Case 1: tank has no drain

In this case, the tank represents an integral system during filling. The container is filled in a linear fashion.

Graphic symbol

Case 1: tank has a drain

If water is withdrawn at the same time via a drain valve, the tank represents a PT1 system (system with

equalisation).

Graphic symbol

Note

Due to the minimal fill level (hydrostatic pressure), the exponential function is not very distinctive.



Systems which demonstrate these characteristics are called 1st order systems. The characteristic variable is

time constant T [seconds]. It’s the time required to achieve approximately 63% of the final level. As system

performance varies, the control circuit also responds variously. In the experiments described below, we will

only examine the performance of a control circuit with a PT1 system.

Task

– How does the integral system perform when the pump is switched off during filling from above?

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– How does the PT1 system perform when the pump is switched off during filling from above?

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4.1 Project task: controlling the fill level using a two-step controller



to find out how a specified fill level can be constantly maintained in the upper tank. There are different

control methods:

· Switch the pump on and off: 2-step control.

· Change control voltage to the pump: analogue control.

Disturbance variables include, for example, opening and closing hand valves V101 and V103, as well as 2-

way ball valve V102 with pneumatic actuation.




– Set the system up with two tanks according to the PI flow diagram.

– Connect the pump, the flow sensor and the 2-way ball valve with pneumatic actuation and test them.


M

P101

V102

PIS+103

FIS+101

B102

V103

B101

V105

V107

LA+111

V112

V101

LS–114

LS–113



4.1.4 Commissioning

– Please check all the points listed in the following report and confirm completion of all tasks before

commissioning.

Task Completed Note/observation

Piping assembled and leakproof



Tank filled with 2.5 litres of water

2-way ball valve with pneumatic actuation installed


Factor = ____________

Offset = ____________

Test pump on/off using PC

Test the signal from the fill-level sensor

4.1.5 Experiment: controlling the fill level using a two-step controller

Fill-level control (discontinuous control) is to be carried out with the pump in binary mode (on/off). The

same experiment, i.e. maintaining a constant fill level by switching the pump on and off manually, was

conducted as part of the learning section on manual control. In the current example, the pump will be

switched on and off by a software controller.

Information

The values in the control circuit are specified in a standardised fashion, i.e. 0 and 1 or 0 and 100%. These

values are frequently converted to physical values for the user, for example so that the fill level can be

specified in litres or the water level in mm.

Designations within the control circuit:

Term Symbol

Setpoint w

Actual value x

Switching difference sd

Manipulated variable (pump on/off) y

As a rule, the value of switching difference sd is at the middle of the setpoint.



Fundamental performance of a control circuit as an example of a fill-level system with open outlet (PT1) and

a 2-step controller

Manipulatedvariable

Setpoint

Switching differenceSignal amplifier Controlled system Sensor

ProcessController

Actual value

w (0...1)

y (0...1) x (0...1)sd (0...1)

Where actual value ß (setpoint - switching difference/2) setpoint with storage = 1

Where actual value à (setpoint + switching difference/2) setpoint with storage = 0

2-step controller logic

Various settings must be entered in order to test performance. In order to be able to draw any conclusions

about the control circuit, it’s always advisable to change only one parameter at a time and then conduct the

experiment. The respective settings included in the following table are suggestions.



– Start the software and open the “Two-step controller” menu.

– Set digital output A3 according to the setpoints and the switching difference from the table.


Settings – standardised values (0 to 1) Observations

Setpoint w Switching difference sd Disturbance variable z:

hand valve V103

1 0.2 0.05 10% open

2 0.4 0.05 10% open

3 0.6 0.05

4 0.4 0.01 10% open

5 0.4 0.1 10% open

6 0.4 0.1 40% open

Sample solution for controlling the fill-level with a 2-step controller



Task

– How does switching difference affect control?

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– How does the interference variable affect the outcome of the experiment?

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Information about the practical use of 2-step controllers

2-step controllers are used wherever system deviation is reliable.

Examples: irons, refrigerators, heaters, solar systems, fill levels for cooling lubricant, fill levels in galvanising

systems and swimming pools etc.

These systems have a large time-constant, so that only minimal switching frequencies occur despite a small

switching difference.



4.2 Project task: controlling the fill level using a continuous controller


If no system deviation is permissible within the control circuit, continuous controllers must be used.

Continuous controllers are characterised by, for example, an analogue manipulated variable in the event

that the sensor has generated an analogue signal. Depending on the control function, the manipulated

variable is calculated by means of various mathematical formulas.

Schematic diagram of a control circuit with a continuous controller

A fill-level system with open outlet (PT1 performance), for example, is used within the control circuit.

Manipulated variable

Y = ...Control function Signal amplifier

Controller

Actual valueSetpointw (0...1)

y (0...1)

Controlled system

Process

Sensor

x (0...1)

The following controller functions (selection) could be used:

Controller Graphic symbol Function

P controller

y = kp · e

kp = adjustable amplification factor

e = system deviation w - x

I controller

y = esum · TA/Ti

Adjustable integral time (Ti)

esum = sum of system deviation e

System deviation e is added up during each cycle.

PI controller

Y = kp · ( e + esum · TA/Tn)

Adjust kp and reset time (Tn)

TA = sampling time, programme cycle time

PID controller

Y = kp · (e+ esum · TA/Tn+ (e-e_alt) · Tv/TA)

Adjust derivative time (Tv),

e_alt = system deviation from the previous cycle

Note

The pump must be operated in the analogue mode for continuous control. Control voltage from the

EasyPort to the motor control is between 0 and 10 V. Changeover relay K1 must be set with A2 = 1 to this

end.



4.2.2 Experiment: controlling the fill level with a continuous controller

In this experiment the fill level will be controlled with a continuous controller. In the example included in the

chapter entitled “Manual control of fill level”, the fill level was kept constant by varying the power supply

unit’s output voltage. The manipulated value will now be read out by the software. The experiment should

be carried out with four different controllers.

Various settings must be entered in order to test the performance of the control circuit. In order to be able to

draw any conclusions, it’s always advisable to change only one parameter at a time and then conduct the

experiment. The settings included in the following table are suggestions.

– Start the software and open the “Continuous control” menu.

– Check the software settings: set changeover relay A2 = 1 and specify the setpoint.

– Carry out the experiment with P, I and PI controllers.

– Add your observations to the table.

Depending on the software revision level, the setpoints may also have to be entered in a sub-window.



4.2.3 Experiment: controlling the fill level using a proportional controller

Note

Empty B102 before each start-up!

– Select each of the values listed below and carry out the experiment.

– Document your observations.

Settings Observations

No. Setpoint w, physical

Setpoint w (standardised)

Amplification kp

Disturbance variable z, hand valve V103

1 1 litre 0.3 0.5 10% open

2 1 litre 0.3 2 10% open

3 1 litre 0.3 10 10% open

4 1 litre 0.3 5 0% open

5 1 litre 0.3 5 20% open

6 2 litres 0.2 5 100% open

Sample solution for fill-level control with a P controller



Task

– Which characteristics is the control circuit (P controller, PT1 system) displaying?

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4.2.4 Experiment: controlling the fill level using an integral controller

Note

Empty B102 before each start-up.

Software setup

The manipulated value of the I controller is calculated as follows:

Y = total of all system deviation (e:sum) x sampling time (TA)/integral action time (Ti)

This formula makes it clear that Y is quickly changed by the controller when Ti is small, and Y is changed

slowly, i.e. the controller is sluggish, when Ti is large. Make sure that Ti does not drop to 0, otherwise Y

would be undefined in this case. Switch the software to “I controller”.

The physical setpoint depends on the size of the tank and whether the unit of measure of the fill level will be

in litres or in mm.








Integral action time (Ti)


1 – 0.3 1 10% open

2 – 0.3 0.5 10% open

3 – 0.3 0.1 10% open

Note

It is possible that no stabilisation occurs in an actual system and that continuous oscillation takes place.

Sample solution for controlling the fill-level with an I controller



Task

– What is the effect of integral time?

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– What can we say about system deviation?

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4.2.5 Experiment: controlling the fill level using a proportional-integral controller (parallel P and I

components)

In order to take advantage of the positive characteristics of both the P and the I controller, the two will be

combined. This can be done in two different ways:

The controllers are connected in parallel in the combination shown on the left and in series in the combination

on the right. In actual industrial practice, the combination shown on the right is used in accordance with DIN

19226.

Note


– Select each of the values listed below for the PI (DIN) controller and carry out the experiment.





No. Setpoint w (standardised)

Amplification kp

Reset time Tn Disturbance variable z, hand valve V103

1 0.5 litres 00.5 1 sec. 10% open

2 0.5 litres 1 1 sec. 10% open


4 0.5 litres 3 0.1 sec. 10% open

Sample solution for controlling the fill-level with a PI controller

Task

– What can we say about reset time Tn?

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4.3 Project task: refrigerating plant


The throughput of a coolant (volumetric flow rate) in a refrigerating plant needs to be controlled. A PI

controller is used. Water will simply be pumped to tank B101 for this experiment.

PI controller Motor and pumpLiquid in pipingsystem

Control circuit concept


– Set the system up with one tank according to the PI flow diagram, or disconnect the piping to upper

tank B102 and seal the bottom outlet of tank B102 with a blanking plug.

– Connect and test the pump and the flow sensor.

M

P101

PI103

FI101

V103

B101

V105

V102

– Install and start the software, and select “Continuous controller” from the menu. Entries are

standardised from 0 to 1.





commissioning.







Factor = _____________ , offset = _____________

Test pump with PC at 0 to 10 V

Changeover relay: A2 = 1

Test the signal from the volumetric flow rate sensor

4.3.4 Experiment: flow control using a proportional-integral controller

Note

Various settings must be entered in order to test performance. In order to be able to draw any

conclusions, it’s always advisable to change only one parameter at a time and then conduct the





Amplification kp


1 0.5 litres 0.5 1 sec. 50% open



4 0.5 litres 3 0.1 sec. 50% open

5 20% open

6 100% open



Sample solution for flow rate control with a PI controller

Task

– Find a setting at which the controller overshoots only once.

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5. Evaluation of learning objectives for automated measurement, open-loop and closed-loop control

1. Describe how to set up a computer aided control circuit.

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2. List various controlled systems with one practical example for each.

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3. Describe the performance of a control circuit with a PT1 system.

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4. Data (e.g. actual value x) is acquired using sensors. The following, for example, appears in a data sheet

for a sensor: pressure range: 0 to 400 mbar, signal: 0 to 10 V. How is the signal processed by the PC so

that the physical value is displayed on the PC monitor?

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5. An ultrasonic sensor provides data in accordance with the following screenshot. Determine factor and

offset for a physical representation of the value on the screen.

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6. A pressure sensor is described as follows in the data sheet:

1

3

2

1: 24 V DC supply voltage 2: 0 V DC earth 3: 0 to 10 V DC voltage output

– Which pins have to be connected to EasyPort?

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– Which values do factor and offset have to be set to in order to display pressure correctly as a physical

quantity?

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7. How are actuators (e.g. pump motor) controlled with the PC?

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8. How is the EduKit PA switched from digital to analogue control?

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9. As is the case with all microprocessor controllers, the PC works cyclically according to the IPO model

(input, processing, output). The time required for a single sequence is called cycle time or sampling time

(TA).

– For example, a programme has a sampling time of 25 ms. How many measurements can be carried out

in one second?

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– In order to determine the flow rate of a medium as accurately as possible, at least 50 measurements

must be performed per second. Determine the required sampling time.

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10. A pump fills a tank from above with water. After a given period of time, the pump is switched off. Draw

conceivable characteristic fill level curves for two different cases: in case 1 the drain at the bottom of

the tank is open. In case 2 the drain is closed.



11. An impeller pump causes volumetric flow rate within a circuit. What is the relationship between

volumetric flow rate and pressure? Give reasons for your answer.

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12. The following figure depicts a characteristic pump curve. Control voltage is increased from 0 to 10 V in

case 1. In case 2, it’s decreased back to 0 V.

– Provide designations for the depicted axes.

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– Give reasons for the shape of the curves.

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13. A two-step controller can be used for simple control of the fill-level.

– Explain the structure of a 2-step controller.

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– What is the effect of the switching difference?

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14. After the process, the process, measurement and control data can be stored as ASCII data.

– Why is ASCII used?

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– How can the data be further processed?

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© Festo Didactic GmbH & Co. KG D1-1

Part D1 – Plant construction with solutions

1. Process description _______________________________________________________________ D1-3

1.1 Technical reference ________________________________________________________________ D1-3

1.2 Economic reference: market research _________________________________________________ D1-6

2. Planning ________________________________________________________________________ D1-9

2.1 Project management _______________________________________________________________ D1-9

2.1.1 Work order, requirements specification _______________________________________________ D1-9

2.1.2 Sequence planning and scheduling, project structure plan,

performance specification _________________________________________________________ D1-10

2.1.3 Purchasing materials and goods ____________________________________________________ D1-13

2.1.4 Standards, regulations, data sheets _________________________________________________ D1-14

2.1.5 Risk assessment _________________________________________________________________ D1-21

2.2 Mechanical engineering ___________________________________________________________ D1-22

2.2.1 Sketches and technical drawings ___________________________________________________ D1-22

2.2.2 PI flow diagram __________________________________________________________________ D1-26

2.2.3 Parts list, mechanical _____________________________________________________________ D1-28

2.2.4 Assembly plan, mechanical ________________________________________________________ D1-29

2.2.5 Quotation and cost calculation _____________________________________________________ D1-31

2.2.6 Test report ______________________________________________________________________ D1-33

2.3 Electrical engineering _____________________________________________________________ D1-35

2.3.1 Electrical circuit diagram __________________________________________________________ D1-35

2.3.2 Parts list, electrical _______________________________________________________________ D1-36

2.3.3 Assembly plan, electrical __________________________________________________________ D1-37

2.3.4 Cost calculation __________________________________________________________________ D1-39

2.3.5 Test report ______________________________________________________________________ D1-40

3. Installation _____________________________________________________________________ D1-43

3.1 Work safety _____________________________________________________________________ D1-43

3.2 Preassembly, mechanical __________________________________________________________ D1-44

3.3 Pre-wiring, electrical ______________________________________________________________ D1-44

3.4 Final assembly with component labelling _____________________________________________ D1-45

4. Commissioning __________________________________________________________________ D1-47

4.1 Mechanical testing, report _________________________________________________________ D1-47

4.2 Electrical testing, report ___________________________________________________________ D1-48

4.3 Overall commissioning ____________________________________________________________ D1-49

4.4 System analysis: evaluation of test reports ___________________________________________ D1-50

4.5 Shipping and product approvals, performance description ______________________________ D1-50


D1-2 © Festo Didactic GmbH & Co. KG

5. Marketing and sales _____________________________________________________________ D1-51

5.1 Quotations ______________________________________________________________________ D1-51

5.2 Product presentation _____________________________________________________________ D1-52

5.3 Documentation __________________________________________________________________ D1-52

5.4 Intellectual property rights _________________________________________________________ D1-53

6. Evaluation of learning objectives for plant construction ________________________________ D1-55



1.1 Technical reference

Information

The subject of plant construction will be examined in greater detail on the following pages. Although plant

construction encompasses several individual disciplines, they can be seen as a whole. Learners will be

introduced to the most important aspects of plant construction using a consistent method based on

practical examples. The knowledge acquired also provides them with an overview of the interaction which

takes place between a variety of professions, such as electrical engineering, mechanical engineering and

process engineering. The overall concept of the MPS-PA project kit is also intended to support the

vocational orientation of pupils and trainees and to encourage young people to pursue technical careers.

General learning objectives

Participants are familiarised with the following topics:

· Project management


· Mechanical and electrical engineering

· Creating flow diagrams and simple circuit diagrams

· Analysing results

· Mechanical and electrical assembly and wiring

· Commissioning with test report

· Marketing and sales



Information

Changing and maintaining fill levels are common daily tasks. These processes usually take place in the

background or within areas of a machine or system that is not immediately visible. Nevertheless, monitoring

process quantities such as fill level, pressure and flow rate offers a great deal of potential. Economy,

improved quality and more safety for personnel and machinery are only a few of the aims which can be

achieved by consistent process monitoring. Below are a few examples of applications in which these factors

play a role.

Pressure monitoring

Example: galvanising plant

The acid bath at a galvanising plant is continuously recirculated and filtered. A filter in the piping system

ensures that contamination and particles are removed. During operation, the contamination is deposited on

the filter and resistance within the piping system increases. As a result, pressure upstream of the filter rises.

Pressure is monitored via a sensor. When a specified pressure is exceeded, the filter must be cleaned or

replaced.



Flow monitoring

Example: water meter

A household water meter continuously measures the occupants’ water consumption by measuring the flow

rate in the fresh water supply line. The consumer relies on a uniformly accurate read-out of actually

consumed quantities. The water utilities are also dependent on the accuracy of the water meter. Deviation

results in a loss for one party and an erroneous gain for the other.

Fill level monitoring

Example: water tower

In order to ensure a constant supply of drinking water, ground, spring or lake water is pumped into water

towers where it’s stored before being distributed to cities and communities. The fill levels in these towers

should be kept as constant as possible, although varying amounts of water are withdrawn by households.

Water flows from the water towers via distributors into the storage tanks of domestic household water

systems. From there it is accessed directly via a water tap or it’s stored again, for example in toilet tanks.



Further examples of pressure, flow and fill level monitoring:

· Pressure must be held constant in water jet cutting systems, even in the event of fluctuating water demand.

· A certain amount of water must be added in order to achieve the desired consistency in a cement mixing

system. The volumetric flow rate is time-controlled and flows constantly.

· Cooling lubricant is pumped into a tank at the machine in order to ensure an uninterrupted supply to

machine tools. Cooling lubricant is withdrawn continually during the machining process. The fill level is

continuously monitored.

· Pumps deliver cooling water from car radiators to car engines in order to prevent them from overheating. A

storage container compensates for volumetric fluctuation due to thermal expansion and loss.

· Liquids are pumped from one tank to the next for storage in filling systems. When a given quantity of

liquid is withdrawn, for example, the fill level has to be evened out.

· Fountains are operated with the help of a pump and a storage tank.

1.2 Economic reference: market research

Information

There are approximately 14,500 water catchment systems in Germany. More than 60% of drinking water is

ground water; the rest comes from rivers, lakes, bank filtrate and springs.

For example, the supply of water for Baden-Württemberg is assured by a joint management authority

consisting of communities, cities and water utilities, namely Bodensee-Wasserversorgung (Lake Constance

water supply). Roughly four million people are supplied with water from Lake Constance, which is pumped

from a depth of 60 metres near the town of Sipplingen. Approximately 130 million m3 of water are

transported through a piping network that is 1700 kilometres long and includes roughly 30 tanks used for

intermediate storage. The largest water tank, with a capacity of 100,000 m3, is located in Baden-

Württemberg’s capital city, Stuttgart.

Task

– Find out about water supply in your city or area.

– Determine the course of the water before it arrives at all the households.



Information

The fill-level system simulates the supply of water from the withdrawal of raw water, for example from a

spring, to the filling of a water tower with the help of a pump up to consumption by households. Two tanks

are available for this project, one of which represents the elevated water tower, and the other the

household’s domestic water tank. The water has to be pumped into the water tower by means of an impeller

pump.

Volumetric flow rates, pressures and fill levels need to be recorded at the system. Variable valve settings

and electrical voltages are used in order to do this.


2. Planning

2.1 Project management

2.1.1 Work order, requirements specification

Information

The system is shipped as individual components and must be set up on-site, both mechanically and

electrically. Various experiments should be carried out, documented and assessed after the system has

been fully set up and tested. The following services, work sequences and documents are specified in the

work order to this end by the customer:

· Mechanical design

· Documentation (text and images)

· Develop and create circuit diagrams

· Generate parts lists/list of components

· Develop an assembly plan

· Plan and carry out wiring and connection of electrical components

· Determine material costs

· Prepare a presentation on the subject of water supply

· Create an approval checklist and report

· Design and implement a graphic evaluation

· Calculate, record and evaluate time required for activities

· Create data sheets for recording measured values

· System commissioning

· Measured value acquisition as an experiment

· Process calculations and technical questions

· Create technical drawings

· Produce components if necessary

2. Planning


2.1.2 Sequence planning and scheduling, project structure plan, performance specification

Information

First of all, in the planning the various tasks, as listed on the work order and the requirements specification,

must be organised and divided in the order in which they will be carried out. The requirements specification

is prepared by the customer and includes all the services to be rendered. The supplier creates the

performance specification on the basis of the stipulations set forth in the requirements specification. In it,

the supplier records the services to be rendered, the activities to be carried out, important dates for

presentations and meetings etc., deadlines for partial and full performance of the obligations and a project

structure plan. The project plan lists the respective activities arranged according to sets of tasks in the form

of a flow chart. These sets are subsequently arranged interdependently in chronological order. This

schedule is called the project sequence plan. The activity lists indicates the planned duration of each step

before the next one can be started.

Task

The performance specification should be put together during the concept phase (see worksheet for

shipment of a completed and functional fill-level system with two tanks). The performance specification is

enhanced during the planning phase.

– Complete the performance specification worksheet (concept phase).

– Create a project structure plan and use it to develop your project sequence plan with the required

procedures in tabular format with a rough time estimate. Use the list of services to be rendered from the

work order for orientation.

– Assemble a project team for the various tasks.

– Use the performance specification to describe the objectives of the project, the people involved, the

quality requirements with regard to setup and functionality of the system, general conditions,

deadlines, milestones and the scope of documentation.

2. Planning


Performance specification

Project name/designation:

Order no.

Customer:

Project employees:

Project no.

Schedule: Intermediate deadlines:

Assembly deadlines:

Completion deadline:

Terms and conditions of

payment:

o Advance payment:

o According to payment schedule:

Concept phase

Description of the product

Description of the range of

applications

Description of the function

Formulation of the

problem/requirements

Done

Technical data

Costs and target prices

Planning phase

Preliminary calculation of

manufacturing costs

Personnel and material costs

Project costs

2. Planning


Item Step designation Duration in days

Preceding activity

Team members

1 Preliminary study and Internet research 2 –

2 Draft of the project concept and a process sequence 1 1

3 Develop and sketch PI flow diagrams and circuit diagrams 3 2

4 List of mechanical components 2 3

5 Develop mechanical assembly plan 2 3, 4

6 Determine costs for mechanical materials 2 2, 4, 5

7 List of electrical components 2 3

8 Create an electrical setup plan 2 3, 4

9 Determine costs for electrical materials 2 2, 7, 8

10 Create performance specification 2 3, 6

11 Carry out mechanical assembly 2 3, 4, 5

12 Complete electrical pre-wiring 2 3, 7, 8

13 Complete cabling 1 3, 8, 12

14 Create a graphic evaluation 2 10

15 Create data sheets for recording measured values 3 10

16 System commissioning (test run) 1 11, 12, 13

17 Carry out experiments 3 16

18 Calculations 1 16

19 Approval meeting 1 17, 18

20 Create overall documentation 3 19

21 User training, conduct experiments 2 19, 20

22 Final meeting and presentation 1 20, 21

Project sequence plan

2. Planning


2.1.3 Purchasing materials and goods

Information

Two important aspects of the planning phase include the procurement of materials and goods. These steps

should be planned carefully and in detail. The timely completion of a project may depend on this in some

cases.

The first step of purchasing materials and goods involves finding a suitable supplier. A suitable supplier can

be selected using the Internet, as well as visits to, and meetings with, potential suppliers.

As a rule, the following steps are completed after selecting a supplier:

· Issue an RFQ:

At this point, product specifications need to be clarified and prices, lead-times and terms and conditions

of payment and delivery have to be negotiated.

· Issue a purchase order:

It’s important to include the correct information on the purchase order. This includes a precise product

designation, the quantity, the price and the delivery date, as well as terms and conditions of shipping

and payment.

· Dispatch the order confirmation:

The supplier sends you an order confirmation after he has received your purchase order.

· All the points which were agreed upon before the order was placed should be reviewed at this time.

Important points include the product designation, the price, the quantity, lead-time and terms and

conditions of payment.

· The goods arrive:

Goods are usually received by the good inwards department, where the shipment is inspected for

damage and/or defects. If any defects are detected, they must be recorded and documented. The

resulting documents must then be submitted to the liable party, i.e. the manufacturer or the supplier.

· The invoice arrives:

Before the invoice amount is finally paid, the prices on the invoice are compared with the prices on the

purchase order in order to rule out any possible errors. The order is closed once the invoice amount has

been paid.

· Carry out final costing:

The purchasing costs are used for final costing. This step is helpful to estimate future projects.

2. Planning


2.1.4 Standards, regulations, data sheets

Information

A process engineering system consists of numerous components from various manufacturers. The

components must comply with uniform quality standards. These standards are specified in accordance with

DIN and EN, as well as ISO, VDE and VDI.

The following standards are taken into consideration and the following data sheets are required to plan and

design the fill-level system in accordance with current knowledge as of 2008:

· DIN 10628 – standard for graphical symbols and flow diagrams for process plants

· DIN 19227, parts 1 and 2 – standard for the graphic representation of process, measurement and

control technology symbols

· DIN EN 22858 – standards for graphical symbols and identifying letters for mechanical components

· DIN EN 61346-2 – standards for graphical symbols and identifying letters for electrical components

· DIN ISO 1219-2 – standards for graphical symbols and identifying letters for pneumatic components

· Data sheets for piping, stopcocks and the impeller pump

· DIN EN 60617, DIN EN 61346-2 – standards for graphical symbols and identifying letters ...

· DIN ISO 1219, DIN EN 60848 – standards for engineering drawings of pneumatic components and

function charts

The standards and stipulations set forth by DIN and VDE as well as the safety precautions for working with

electrical current and voltage, must be observed for all electrical work.

Technical information about the components is included in the data sheets on CD-ROM.

Electrical components

The respective devices are designated in the electrical circuit diagrams in accordance with DIN EN 61346-2.

Type of equipment Identifying letter

Actuators (servo drive, actuating coil, electrical motor, linear motor) M

Diodes R

Auxiliary relays K

Terminals, terminal blocks, terminal strips X

Capacitors C

Circuit breakers, isolating switches Q

Power transistors Q

Indicators (mechanical, optical, acoustic) P

Relays K

Tubes, semiconductors

Contactors (for load) Q

Sensors in general, position switches, proximity switches, proximity sensors etc. B

Fuses F

2. Planning


M

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224

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43M

otor

Ans

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Mot

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XMA

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A1(

STA

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0VA

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2K10 7.

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M2M

1

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bk)

2

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1114

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2K1

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2K10 7.

5

21 22 7.7/ERR

24

2K1 .3

11 14

2M2+

2M3

+ 0VA

2M4

4 O3

0VA

2M

5

5 O4

0VA

6 O5

0VA

7 O6

0VA

BN

BU

BK

2PA

_ B

USY

+8 O7

0VA

/6.0

24V

B /6.0

0VB24

VA

0VA

FED

24VA

24V

0V

0VA

3 O2

++

Example of an electrical circuit diagram – MPS® PA mixing station, outputs

2. Planning


Pneumatic components

Pneumatic components are designated in circuit diagrams in accordance with DIN ISO 1219-2. All the

components included in any given circuit have the same primary identifying number. Letters are assigned

depending on each respective type of component. Consecutive numbers are assigned if several components

of the same type are included within a single circuit. Pressure lines are designated with a P and are

numbered separately.

Actuators: 1A1, 2A1, 2A2 ...

Valves: 1V1, 1V2, 1V3, 2V1, 2V2, 3V1 ...

Sensors: 1B1, 1B2 ...

Signal input: 1S1, 1S2 ...

Accessories: 0Z1, 0Z2, 1Z1 ...

Pressure lines: P1, P2 ...

Identifiers for pneumatic components also include a system number (“1-... ... ...”) which appears to the left

of the circuit number, the component identifier and the component number.

2. Planning


1M

1

1M

4

1

12

3

2

BN

BK

BU

RU

1 4 3

WH

2R

I

UP

1B

1

1V

1

1-2V

1

1-2V

21-

2V3

V103

V10

21-

1A1

_1B

9

_1B

7

_1B8

_1B6

13

SOLL

IST

2

PE

PRO

P_V

1-1V

3

max

. 2b

ar

1-1V

2

I

14

24

35

11

M5

1-3V

1

1-3V

21-

3V3

14

24

35

1

1-3A

1

V10

6

1M

6

1-4V

1

1-4V

21-

4V3

14

24

35

1

1-4A

1

Example of a pneumatic circuit diagram – MPS® PA filtering station

2. Planning


Process engineering components

Components are designated in the PI flow diagram in accordance with EN ISO 10 628 and DIN 19227-1.

M

P202

V207

V209

V211

B20

4

LS+

LA+

205

212

LS-

206

V210

M

P201FI FIC

202

201

LS-

204

B20

3

V203V2

04

LA+

211

LS-

203

B20

2

V205

V202

LA+

210

LS-

202

B20

1

V206

V201

LS+

201

LA+

213

V208

X201

X202

Example of a PI flow diagram – MPS® PA mixing station

2. Planning


EN ISO 10628 standard

The layout and function of a process engineering system are described in a piping and instrument flow

diagram (abbreviated PI flow diagram).

Apparatus or machinery Identifying letter

System section or machine if not assigned to one of the following groups A

Container, tank, hopper, silo B

Chemical reactor C

Steam generator, gas generator, oven D

Filtration device, liquid filter, sieve, separator F

Gear unit G

Lifting unit, conveying unit, transfer unit H

Column K

Electrical motor M

Pump P

Stirrer, stirring container with stirrer, mixer, kneader R

Centrifuge S

Dryer T

Compressor, vacuum pump, fan V

Heat exchanger W

Feed and separating equipment, other devices X

Actuator unit, other than electrical motor Y

Crusher Z

Identification of process engineering components

DIN 19227-1 standard

In addition to system components, process, measurement and control points are also included in PI flow

diagrams. The process related functions of the measured quantities are described by means of process,

measurement and control points per DIN 19227-1. The identifier should indicate the measured quantity or

another input quantity, how it’s processed, its direction of control action and its specified location.

A process, measurement and control point consists of a circle and is designated with an identifying letter (A to

Z). The identifying letters are entered in the top part of the circle and numbering is entered in the bottom part.

The order of the identifying letters is as per the table, “Process, measurement and control identifying letters

per DIN 19227-1”.

Example L I C

Lic

First letter Supplementary letter First subsequent letter

Fill level Display Automatic control

2. Planning


The identifying procedure for process, measurement and control points is freely selectable. Consecutive

numbering is advisable because each process, measurement and control identifier may only be used once,

even if there are several measuring points with the same measured quantity.

Further information can be found in DIN 19227, part 1.

Process, measurement and control identifying letters per DIN 19227-1

Letter Measured quantity or other input quantity, actuator “Processing

Subsequent letter Sequence: O, I, R, C, S, Z, A”

First letter Supplementary letter

A Error message

B

C Automatic control

D Density Difference

E Electrical quantities Sensor function

F Flow, throughput Ratio

G Distance, length, position

H Manual entry, manual intervention Upper limit value (high)

I Display

J Sensing of measuring points

K Time

L Level (also separation layer) Lower limit (low)

M Moisture

N

O Visible sign, yes-no statement

P Pressure

Q Material characteristics, quality Integral, sum

R Radiometric quantities Recording

S Speed, frequency Switching, sequence control, logic control

T Temperature Measuring transducer function

U Combined quantities Combined actuator function

V Viscosity Actuator function

W Weight, mass

X Other quantities

Y Calculation function

Z Emergency intervention, protection by means

of triggering, safety device, safety relevant

message

+ Upper limit value

/ Intermediate value

– Lower limit value

2. Planning


Task

– Familiarise yourself with the standards and data sheets.

– Which information do the above mentioned standards and data sheets provide you with?

– Create a summary of the most important characteristics for each standard and the components used.

2.1.5 Risk assessment

Information

An important aspect of the planning phase is the risk assessment. All machinery and equipment

manufacturers are required to carry out a risk assessment for their machines and equipment. This is a legal

requirement and is stipulated in the EC machine directive. The directive states: “The manufacturer of

machinery or his authorised representative must ensure that a risk assessment is carried out in order to

determine the health and safety requirements which apply to the machinery. The machinery must then be

designed and constructed taking into account the results of the risk assessment.”

Below is an example of what a risk assessment might look like.

2. Planning


2.2 Mechanical engineering

2.2.1 Sketches and technical drawings

Task

– The scale of the overall drawing of the fill-level system is 1:5. Add the most important assembly

dimensions to the drawings so that it can be used later to set up the system.

350

165

200

27

Top view

2. Planning


415

Front view

2. Planning


100

300

Side view, right

2. Planning


– The rectangular profiles to which the tanks are attached are joined with retaining plates. Manually

sketch out the hole pattern for the retaining plates for M5 socket head screws.

20

20

40

Ø6

– The retainer for the impeller pump has to be made. Calculate the length of the sheet metal.

Ø42

18

68

40

12

Ø5,5Ø5,5

a, b, c ... Lengths of bending sections

n number of bends

v compensation value; v = 3 mm for a sheet metal thickness of 1 mm and a bending radius of 4 mm

L = a + b + c + ... - n · v

Where arc sine a = 9 mm/21 mm a = 25.38° opening angle = 50.75°

L = 2 · 14 + 2 · 11 + 2 · 12 mm + p · 42 mm · 309.24°/360° - 4 · 3 mm

L = 175.34 mm

2. Planning


2.2.2 PI flow diagram

Information

The piping and instrument flow diagram (PI flow diagram) depicts the technical equipment included in a

system with the help of graphical symbols which are connected using lines. The graphical symbols represent

the system components and the lines identify lengths of pipe, as well as electrical functions and signals for

process measurement and control.

The designation V101 from the PI flow diagram is a process designation. Process related tasks are described

in a process, measurement and control plan using graphical symbols, i.e. process, measurement and control

points. The identifier should indicate the measured quantity or another input quantity, how it’s processed,

its control action and its specified location. A process, measurement and control point consists of a round,

oval or hexagonal symbol and is assigned an identifying letter (A to Z). The identifying letters are entered in

the top part of the symbol and a number is entered in the bottom part. The order of the letters is specified in

the table entitled “Identifying letters for process, measurement and control technology” per DIN 19227.

Task

– Fill in the missing designations.

– Create a PI flow diagram for the system using the components from the table.

Components list

Identification Graphical symbol Meaning of the graphical symbol

B101

B101

Tank, container

V102 V102

Stopcock

FI101 FI101

Flow rate measuring point with

display

PI103 PI103

Pressure measuring point with display

P101 P101

Pump

Piping inlet

Piping outlet

2. Planning


PI flow diagram

M

P101

V102

PI103

FI101

B102

V103

B101

V105

V101

PI flow diagram, EduKit PA project kit

2. Planning


2.2.3 Parts list, mechanical

Task

The components and their required quantities can be determined from the overall drawing and the PI flow

diagram for the purpose of creating a parts list. The part numbers are included in the data sheets and the

Festo Didactic product catalogue.

– Using this information, create a parts list for the basic mechanical setup of EduKit PA without electrical

components.

2. Planning


Item Quantity Name Part number

1 1 Pump 170712

2 1 Pressure gauge 162844

3 1 Float-type flow sensor 691225

4 4 Stopcock 170703

5 2 Profile connector

6 3 Rectangular profile, 40 x 20

7 2 Tank (container)

8 5 90° straight plug connector 170701

9 4 Push-in T-connector 170702

10 1 Profile plate, 350 x 200 mm

2 m Straight length of pipe 304518

4 Blanking plug

2.2.4 Assembly plan, mechanical

Information

In order to keep assembly of the system as simple as possible, components are grouped into sub-

assemblies.

Task

– Create an assembly plan for the basic setup of the fill-level system using the table on the next page.

– Write out a set of procedures, indicating how you would assemble the system. Sub-assemblies are

numbered consecutively with the designations B1, B2 and so forth. (The “Times” column refers to a task

in a later chapter and can be disregarded for this exercise.)

2. Planning


Sub-assembly

Item Work step Tool Work step carried out

Times

B1 1 Secure pump, tubing and piping length with pipe clip. Screwdriver

B1 Return line and outlet connection at pump

B2 2 Preassemble pressure gauge and push-in T-connector.

B2 3 Connect the float-type flow sensor to the push-in T-

connector.

B3 4, 9 Connect the transverse line to the tanks with stopcocks

(2 ea.), push-in T-connectors (2 ea.), 90° push-in

connectors (2 ea.) and pipe.

B4 4, 8 Connect the upper feed line to the stopcock (1 ea.), 90°

push-in connectors (2 ea.) and pipe.

B5 7, 6 Screw the tank brackets (4 ea.) onto the rectangular

profiles.

Allen key

B5 6, 16 Screw rectangular profiles with foot to the profile plate. See above

B5 6, 5 Screw rectangular profiles (4 ea.) together with profile

connectors.

See above

B5 7 Set the tanks into the brackets and secure with socket

head screws.

See above

B1 Secure subassembly B1 on the profile plate to the pump

retainer.

See above

B2 Plug subassembly B2 on B1 into the pump.

B3 Connect subassembly B3 to the tanks and plug it into B2.

B4 Plug subassembly B4 into the push-in T-connector at B3

and feed it through the cover on the upper tank.

Tighten all screws once again. See above

Assembly plan, mechanical

2. Planning


2.2.5 Quotation and cost calculation

Information

A fill-level system is required in another department within your company for training purposes. First of all,

you’ll produce a complete basic setup in the form of a prototype in the training department. The fill-level

system will then be sold to the respective department. Determine an estimated sales price in the form of a

simple cost calculation. Electrical and mechanical components should be listed separately. Use the

following quotation as a basis for your calculation:


1 1 Basic mechanical components kit with aluminium

profiles, including all accessories

125.00 €125.00

2 2 Tank, MPS-PA-B tank, round 201.00 €402.00

3 1 Pump, 170712 474.00 €474.00

4 1 Flow meter, 691225 145.00 €145.00

5 1 Pressure gauge 15.90 €15.90

6 2 m Pipe, 304518 8.60 €17.20

7 5 Push-in connector, 170701 4.20 €21.00

8 5 T-distributor, 170702 5.00 €25.00

9 4 Push-in bracket, 690590 5.60 €22.40

10 6 Stopcock, 170703 19.70 €118.20

11 2 Blanking plug, 170705 1.90 €3.80

Net price €1369.50


Task

– Calculate the costs for the fully assembled mechanical portion of the system. Costs are calculated

separately for the mechanical and electrical parts while the cost calculation for the electrical

components will be completed later (see 2.3.4). The prices of the components can be taken from the

above quotation. Manufacturing wages and overheads, as well as administrative and sales costs can be

based on figures provided by the appropriate people in your company, researched on the Internet or

estimated for the purposes of a rough calculation. Make a rough estimate of the time required for

assembly in order to determine labour costs. Use local hourly rates for this.

2. Planning




components


bookkeeping

5% of (1)







Special manufacturing costs (7) Production, fixtures, outsourced

processing (e.g. hardening)




Profit (11) . . . % of (10)

Net sales price Sales price without value added tax Total of (10) + (11)

Gross sales price Sales price with value added tax

Simple cost calculation for mechanical assembly

Task

– When you buy components, a difference is made between net and gross prices. What’s the difference?

Calculate the gross sales price for the above example.

Net prices are prices which do not include value added tax.

Gross prices are prices with value added tax.

Net sales price x VAT rate = gross sales price.

– What’s meant by “overheads”?

Fixed costs, for example for warehousing, training, labour, bookkeeping etc.

2. Planning


– What’s meant by manufacturing costs?

Manufacturing costs are part of the production costs, but they do not include costs related to materials.

Costs for premises and energy are also incorporated into the calculation, as well as special direct costs

(special parts) and the costs of production planning and quality control.

2.2.6 Test report

Information

Once mechanical assembly has been completed, the fill-level system and all its components must be

inspected and approved (i.e. screw connections in the pipe fittings, straightness and parallelism of the

piping, tank mounting, profiles and the impeller pump).

In actual practice, test reports are used to document the functionality and the condition of the system. Test

report requirements are specified either by the customer or by currently valid standards.

Task


entries:

- Test points are numbered consecutively in a tabular report and the numbers are added to the

picture below.


and comments.



inspection.

A sample test report is included on CD-ROM.

2. Planning


Mechanical assembly without electrical actuation

2. Planning


2.3 Electrical engineering


Information

The impeller pump is turned on and off using a detented switch in the basic setup. The pump’s on/off status

is displayed by an indicator light. The impeller pump is supplied with 24 V DC power via a power supply unit.

Task

– Create an electrical circuit diagram for the system and identify all the components. All the system’s

electrical components must be designated in accordance with DIN EN 60617.

Circuit diagram

24 V

3

4

0 V

S1

MP101 P1

2. Planning


2.3.2 Parts list, electrical

Information

The parts list for the electrical components must be planned. The item numbers for the various components

are shown in the following figure.

Task

– Complete a part list for the entire electrical assembly. The part numbers can be taken from the data

sheets and the Festo Didactic product catalogue.

– Put a tick mark in the column “Components for basic setup” for each component required for this task.

– Which additional consumables will be required?

Estimate the amount.

2. Planning


Item no.

Quan-tity

Name Designation, standard designation

Components for basic setup

10 1 24 V DC indicator light with mounting bracket x

11 1 Electrical control switch with mounting bracket x

12 1 Electrical start pushbutton with mounting bracket

13 1 Electrical stop pushbutton with mounting bracket

14 1 Relay with mounting bracket

15 1 Terminal block x

17 1 Wire x

18 1 Mountable plug block x

19 1 H-rail x

20 1 Rail for control components x

1 24 V power supply unit x

Blue wire, 0.5 sq. mm (cross section?) x

Cable binder (size?) x

Wire end sleeves

Bill of materials

2.3.3 Assembly plan, electrical

Information

To optimise work sequences, the order in which work steps are carried out to produce a product should be

planned and documented by the production planning department.

Task

– Arrange the work steps in a logical order with the help of the parts list.

List the wiring and assembly steps for the electrical components in the setup plan. Electrical

components are designated E1, E2, etc. (The “Times” column refers to a task in a later chapter and can

be disregarded for this exercise.)

2. Planning



E1 10 to 14 Mount indicator light, pushbuttons (2 ea.), control

switch, relay and terminal block on the H-rail.

Allen key

E1 Cut wire to length, strip insulation and crimp on the wire

end sleeves.

Wire strippers, crimping

pliers

E1 10, 11 Connect the following electrical components with blue

wires for the basic setup: detented switch and indicator

light.

Screwdriver

E1 Screw the H-rail with the components onto the profile. Allen key

E2 1 Connect the pump to the plug.

E3 Connect the 24 V DC cable to the terminals. Screwdriver

Run cables and bind together neatly, cut the cable ends

to length.

Wire cutter

Assembly plan, electrical

– Add the connecting cables to the image of the electrical components to indicate how they have to be

wired according to the circuit diagram prepared earlier.

2. Planning


2.3.4 Cost calculation

Task

– On the basis of the quotation, determine an estimated sales price for the electrical components and

electrical wiring with the help of a simple cost calculation. Manufacturing wages and overheads, as well

as administrative and sales costs can be based on figures provided by the appropriate people in your

company, researched on the Internet or estimated for the purposes of a rough calculation. Make a

rough estimate of the time required for assembly in order to determine labour costs. Use local hourly

rates for this.


10 1 24 V DC indicator light with mounting bracket 17.00 €17.00

11 1 Electrical control switch with mounting bracket 17.00 €17.00

12 + 13 2 Electrical start pushbutton with mounting bracket 10.00 €20.00

14 1 Relay with two changeover contacts 18.00 €18.00

15 6 Screw terminals 1.07 €6.42

17 1 3-core safety laboratory cable 17.00 €17.00

18 1 Mountable plug block 2.90 €2.90

19 1 H-rail 1.90 €1.90

20 1 Rail for control components 24.00 €24.00

1 Table top power supply unit with power cable, 230 V AC,

24 V DC / 4.5 A

351.00 €351.00

Net price €475.22


2. Planning




components


bookkeeping

5% of (1)







Special manufacturing costs (7) Production, outsourced processing (e.g.

ready-wired components)




Profit (11) . . . % of (10)

Sales price Net price without value added tax Total of (10) + (11)

Calculation plan

2.3.5 Test report

Information

Once electrical assembly has been completed, the wiring, interconnection of the electrical components such

as switches and the indicator light and the mechanical attachment of the electrical components are

inspected and approved.

Task


entries:

- Test points are numbered consecutively in a tabular report and the numbers are added to the image

below.


and comments.



inspection.

A sample test report is included on CD-ROM.

2. Planning


Setup with electrical wiring

2. Planning



3. Installation

3.1 Work safety

Information

Work instructions specify in detail how certain steps have to be carried out. Work instructions are tied to a

specific process, a product or a workstation. They form the basis for ensuring that quality standards are met

when the company’s employees carry out their respective tasks. Initial basic instruction on safety in the

workplace and how each person should comply must be completed before specific work instructions are

handed out.

Observe the safety precautions in the introduction!

Safety instructions

Mr./Ms.

Department

Job

Received instructions in accordance with § 7 UVV, VBG 4 and on the basis of the activities carried out at the workstation.

Subject of instruction Date Instructed person (signature)

Supervisor (signature)

1. General instructions at the fill-level system

2. Instructions on handling liquids

3. Instructions for electrical components

4. Electrical start-up must only be carried out by

appropriately trained personnel.

5. General introduction to: Workshop use

Goods in/out

Working at a PC

Internet and e-mail

Telephone system

Accident prevention regulations specified by trade associations for precision and electrical engineering apply.

3. Installation


3.2 Preassembly, mechanical

Information

The components must now be assembled in accordance with the specifications in the assembly plan.

Task

– Complete the mechanical preassembly of the components of the fill-level system first. Supplement the

assembly plan you created in the chapter on “Planning” by assigning assembly procedures to

components. Use the technical drawings of the components as an assembly guideline. Engineering

drawings of the individual components are included on CD-ROM.

– Write down the assembly times in the assembly plan prepared earlier and modify it if necessary if you

use different steps or discover better alternatives.

3.3 Pre-wiring, electrical

Information

The components are preassembled in accordance with the basic electrical setup plan.

Task

– First of all, the electrical components are pre-wired. Proceed in accordance with the layout you have

already created. Follow the circuit diagram with regard to wiring. Then attach the electrical components

to the H-rail.

3. Installation


– Write down the assembly times and modify the assembly plan if necessary if you use different steps or

discover better alternatives. Make a note of any changes to the assembly plan.

3.4 Final assembly with component labelling

Information

All the mechanical and electrical components are put together in the final step.

Task

– During final assembly, screw or clamp all the mechanical and electrical components to the profile plate

and the rectangular profiles and connect the electrical components to each other (see CD-ROM).

– Supplement the components list with the component designations in accordance with the PI flow

diagram and the electrical circuit diagram. Write the designations of the components onto the adhesive

labels and attach them to the respective system components.

3. Installation



1 P101

Pump P101

2 PI103

Measuring point for pressure

measurement with display (component:

pressure gauge)

PI103

3 FI101

Measuring point for flow measurement

with display (components: float-type

flow sensor)

FI101

4 V102

Stopcock (4) V101, V102, V03, V105

7

B101

Tank, container (2) B101, B102

Component list per PI flow diagram


10

P1

Indicator light, start P1

11 S1

Electrical control switch S1

12 S2

Electrical pushbutton, start S2

13 S3

Electrical pushbutton, stop S3

14 K1

Relay K1

Components list based on electrical circuit diagram


4. Commissioning

4.1 Mechanical testing, report

Information

The fill-level system has now been set up and should first of all be filled. Disconnect the system from the

power supply before commissioning. In order to prevent any unpleasant surprises, check the mechanical

components both before and during filling. Keep an adequate supply of rags on hand in order to mop up any

water which might escape.

Task

– Check the points listed below and acknowledge inspection.

Commissioning, report – mechanical


Stopcock V 105 closed

Impeller pump pipe connection complete and securely pushed in place

Stopcock V 101 for filling the upper tank from above closed

Stopcock V 103 for filling the upper tank from below closed

Stopcock V 102, lower tank return line, closed

Fill the upper tank, check for leaks


Open stopcock V 102 (lower tank return line open)

Fill the lower tank, check for leaks


Place a bucket underneath, open stopcock V 105 and drain the tank

Inspector Date

4. Commissioning


4.2 Electrical testing, report

Information

Once mechanical inspection has been completed, the electrical components are tested to ensure they

function correctly. This is done by filling the system with water, so that the pump is prevented from running

dry. First, the water is only pumped around in a circular direction, i.e. from the bottom container via the

impeller pump and back into the lower tank from the upper tank.

Task

– Carry out all the commissioning steps.

– Evaluate your results and tick off the corresponding entry. If the function is not performed correctly,

make a note of the determined status or the sub-function. Discuss appropriate measures for eliminating

the cause of error with your trainer.

Commissioning, report – electrical

Function Fulfilled Not fulfilled, comment


Electrical control switch wired


Pump wired

Secure wires with cable binder


Switch the power supply unit on, the indicator light on the power supply unit lights

up.

Control switch ON, indicator light switches on

Control switch ON, pump runs

Control switch OFF, indicator light does not switch on

Pump vented?

Control switch OFF, pump does not run

Power supply unit OFF, system is shut down

Inspector Date

4. Commissioning


4.3 Overall commissioning

Information

You have approved the system’s mechanical and electrical parts. Now start an initial, complete test run with

all of the system’s components.

Before each time you commission the system, carry out a visual inspection. Inspect the following before

starting the system:

· Electrical connections

· Correct fitting, leakproofness and condition of piping and pipe connectors

· Correct fitting and condition of compressed air connections, if pneumatic valves are used

· Mechanical components for visible defects (cracks, loose connections etc.)

· Fill level of tank B101

Eliminate any damage discovered during inspection before commissioning.

Supply the system with 24 V DC power via a mains power supply unit.

Task

– Carry out the following steps for (re-)commissioning:

1. Prepare the workstation.

2. Conduct visual inspection.

3. Inspect cable connections.

4. Activate supply power.

5. Fill the tanks.

6. Vent the piping system

– Set the stopcocks so that the following tasks can be carried out:

- Full upper tank B102 from above, stopcock V102 in tank B101 opened about 20%. V101 open,

cV103 closed.

- Fill upper tank B102 from below, stopcock V102 in tank B101 opened about 20%. Open V103, close

V101.

4. Commissioning


4.4 System analysis: evaluation of test reports

Information

The test reports have to be analysed and conclusions must be drawn based on the work done while setting

the system up so that the system’s design and layout can be analysed and improvements made. The

commissioning test reports for mechanical and electrical components are available and overall

commissioning has also been completed.

Task

– Evaluate the test reports and pinpoint any problems.

Use the first practical test run to draw conclusions for further work with the system. Analyse the overall

layout of the system in order to determine whether or not the assembly and commissioning procedures can

be improved. Document your evaluations in writing.

It’s difficult to maintain a specific fill-level using the ON/OFF operating mode for the pump.

If the pump continues to run when the storage tank is empty, air is drawn in. This can lead to

malfunctioning.

4.5 Shipping and product approvals, performance description

Information

Once prototypes have been developed, the first samples are produced under series manufacturing conditions.

The product is not approved until the function, quality and performance features have been examined and

tested. Subsequent series manufactured parts must conform to the same quality standards as the first

samples.

The product must be approved by general management before it can be launched. All information relevant

for sales must be available as a basic prerequisite for the product’s introduction onto the market (see

chapter 5, “Marketing and Sales”).



5.1 Quotations

Information

A great variety of information is required in order to sell a product. For example, the text for a quotation

template must be prepared.

Task

– Find out how quotations are laid out and what information is included. Base yourself on the layout and

content of a quotation from your company or another manufacturer.

– Which details are included in a quotation?

Contact person, company, date of quotation

Information regarding services and the product range

Designations, prices and quantities of quoted items

Lead-times, terms of delivery

Terms and conditions of payment

Quotation validity

– Create a sample quotation for a customer who wants to purchase the project kit.

– What does the term “ex works” mean?

In this case, the contractual obligations of the seller are fulfilled as soon as the ordered goods are ready

for pick-up at his factory or warehouse. The costs of loading and shipping the goods to their destination

are borne by the buyer. The risk of damage to the goods sustained during transport is transferred to the

buyer as soon as loading begins.



5.2 Product presentation

Information

The way in which a product is presented plays an important role in how well it will sell. Companies invest

large sums of money in product marketing. The most important points are briefly discussed below.

Task

Various types of product presentations are created in small groups.

– Brochure, leaflet, foreign languages

A brochure or a leaflet should be printed for the project kit. Important content for any printed

information includes an overall view of the system, interesting partial views, a functional description,

features and technical data of the individual components and notes regarding the user-friendliness of

the piping system thanks to the push-in connector system.

Write the text for the functional description and the technical data in German and English, and add both

languages to the leaflet. The technical data for the various components are included on CD-ROM.

– Screen presentation

The system will be presented to a customer. Create a screen presentation which covers the most

important features and functions of the system. Use the texts for the brochure, but condense them for

the screen presentation. The screen presentation can also be laid out as a PDF file, so that it can be

printed out. Photos of the system are included on the CD-ROM.

– Internet presentation

Edit the screen texts and images so that they can be used in a start-up page for the Internet. Create an

HTML page for the project kit with the help of an HTML editor.

5.3 Documentation

Information

The technical documentation is intended to provide the recipient of the product with information and

instructions regarding the system or the product. In addition, the customer is also made aware of safety

precautions and provided with operating instructions for the system.



Task

– The entire project must be documented. The documentation should include the following information:

- System layout

- Description of functions

- Data sheets for the various components

- Experiment descriptions

- Tables with values and evaluations resulting from the experiments

- Findings

- Circuit diagrams

- Drawings

5.4 Intellectual property rights

Information

As a result of intellectual property legislation for the protection of industrial property rights, the holder of

the rights is granted the opportunity of prohibiting commercial exploitation of the protected objects by any

other party. The intellectual property rights are thus rights of prohibition. They are not – at least not

automatically – rights of use.

Task

– Which types of protective rights are there? Research this topic on the Internet.

Patent

Utility model

Registered design

Variety protection

Trademark protection

Copyright


6. Evaluation of learning objectives for plant construction

1. During which phase of system setup is the project structure plan used?

The project structure plan is used during the planning phase.

2. What is the function of the project structure plan?

Activities are arranged hierarchically and in relation to preceding activities in the project structure plan.

3. Calculate the flat length for the pump bracket assuming a bending radius of 4 mm and a sheet metal

thickness of 2 mm. Use a compensation value of 4.5.

Calculation: where arc sine a = 9 mm/21 mm; a = 25.38°; opening angle = 50.76°

L = a+b+c+…-n·v

L = 2·25 mm + 2·12 mm + p·42 mm·309.24°/360° - 4·4.5

L = 169.35 mm

The flat length of the sheet metal for the pump bracket is 169.35 mm.

4. How are the following functions designated in a PI flow diagram?

Hand valve, no. 102: V102

Measuring point for pressure measurement with display, no. 103: PI103

Measuring point for flow measurement with display, no. 102: FI102

5. Sketch the graphical symbols for a PI flow diagram (see planning):

Pump P101

P101

Measuring point for flow measurement with display, no. 101: FI101

FI101

Pneumatic 5/2-way valve, no. 103

4 2

315



6. Draw the PI flow diagram for pressure measurement while filling the upper tank from below.

See flow diagram on page 25.

7. Which information is included in a part list?

Item number, quantity, designations of the components, standard designation, designation of materials

8. What’s included in a tabular assembly plan?

Item numbers, module numbers, component designations, auxiliary materials, tools

9. When you buy components, a difference is made between net and gross prices. What is the difference

between these prices?

Net prices are prices which do not include value added tax.

Gross prices are prices with value added tax.

10. Name typical overheads?

Fixed costs, for example for warehousing, training, labour, bookkeeping etc.

11. What’s meant by manufacturing costs?

Manufacturing costs are part of the production costs, but they do not include costs related to materials.

Costs for premises and energy are also included in the calculation, as well as special direct costs (special

parts) and the costs of production planning and quality control.

12. During initial testing, you started the pump with a detented switch. Why is a detented start-up switch

impermissible in actual practice?

In actual practice, an on/off switch is impermissible because for safety reasons the system would have to

be protected against being restarted after a power failure, or in the event of power interruption due to an

emergency stop. The system can only be restarted by activating a pushbutton.



13. Cite one safety precaution each for electrical, pneumatic and mechanical components and process

technology

See introduction.

14. Why is a commissioning report prepared after final assembly has been completed and before

commissioning? Cite two examples.

All of the characteristics of the system are tested with the help of the commissioning report, in order to

ensure safe operation.


Part D2 – Practice-based learning: manual measurement, open-loop and closed-loop control with solutions

1. Manual measurement _____________________________________________________________ D2-3

1.1 Project task: bath recirculation ______________________________________________________ D2-3

1.1.1 Task description ____________________________________________________________________ D2-3

1.1.2 Setting up the system, inspection ______________________________________________________ D2-4

1.1.3 Experiment: mechanical pressure measurement __________________________________________ D2-5

1.1.4 Evaluation and findings ______________________________________________________________ D2-6

1.2 Project task: mixing system _________________________________________________________ D2-9

1.2.1 Task description ____________________________________________________________________ D2-9

1.2.2 Experiment: flow measurement _______________________________________________________ D2-10

1.2.3 Evaluation and findings _____________________________________________________________ D2-11

2. Manual open-loop control _________________________________________________________ D2-13

2.1 Project task: controlling water supply using hand valves ________________________________ D2-13

2.1.1 Task description _________________________________________________________________ D2-13

2.1.2 Mechanical layout ________________________________________________________________ D2-14

2.1.3 Setting up the system, inspection ___________________________________________________ D2-16

2.1.4 Experiment: filling the upper tank from below _________________________________________ D2-16

2.1.5 Experiment: filling the upper tank from above _________________________________________ D2-17

2.1.6 Evaluation and findings ___________________________________________________________ D2-18

2.2 Project task: controlling water supply using 2-way ball valve ____________________________ D2-20


2.2.2 Mechanical layout, inspection ______________________________________________________ D2-21

2.2.3 Plans ___________________________________________________________________________ D2-22

2.2.4 Commissioning, report ____________________________________________________________ D2-25

2.2.5 Experiment: filling using a pneumatically controlled 2-way ball valve _____________________ D2-26


2.3 Project task: electrical control of the pump in the water supply line _______________________ D2-27



2.3.3 Relay circuit with pushbuttons _____________________________________________________ D2-28

2.3.4 Electrical circuit diagram __________________________________________________________ D2-29

2.3.5 Electrical wiring and setup plan _____________________________________________________ D2-30

2.3.6 Commissioning, electrical testing and report __________________________________________ D2-31

2.3.7 Experiment: filling while simultaneously withdrawing water _____________________________ D2-32


2.3.9 Experiment: pump start-up performance and power ____________________________________ D2-34




3. Manual closed-loop control _______________________________________________________ D2-37

3.1 From a control loop system to a control circuit ________________________________________ D2-37

3.2 Project task: controlling the fill-level in the tanks ______________________________________ D2-39



3.2.3 Experiment: manually keeping the fill level constant in the upper tank ____________________ D2-40


3.2.5 Experiment: controlling the fill level using an analogue controlled pump __________________ D2-43


3.2.7 Experiment: pressure and flow control _______________________________________________ D2-44


4. Evaluation of learning objectives for manual measurement, open-loop and

closed-loop control _______________________________________________________________ D2-47





Information

Typical recirculating processes are used in all baths where liquids have to be filtered. For example, leisure

time applications include swimming pools and technical applications include acid baths and galvanising

plants. As the filter becomes more and more contaminated, resistance in the piping system increases

upstream of the filter in proportion to the degree of contamination. When a specified pressure is exceeded,

the filter must be cleaned or replaced. The relationship between resistance (degree of valve opening) and

pressure is determined by experimentation.

Task

– Modification in accordance with the PI flow diagram: modify the basic setup with two tanks so that the

experiments for manual measurement can be done using a single tank. Stopcock V103 represents the filter

for the purpose of the experiment. Filter permeability is simulated by opening and closing the valve.

M

P101

V102

PI103

FI101

V103

B101

V105




Work step Done

Modify the piping layout in accordance with the photograph. Remove the piping to the upper tank and insert

blanking plugs into each of the push-in T-connectors.




Make sure that the pressure gauge is installed directly downstream of the pump!

Fill tank B101 with 3 litres of water.


Test execution:

Stopcocks V103 and V102 are fully open and V105 is fully closed. The control switch is turned to the ON

position and the pump delivers water. Stopcock V103 is closed successively in the test setup.

After the experiment has been completed, pull out the main plug and remove the 4 mm safety cable from

the power supply unit.

The water must be drained from the system via stopcock V105 after testing.



1.1.3 Experiment: mechanical pressure measurement

Fill the tank and then start the pump. Stopcock V103 is open at first and is gradually closed. Stopcock V103

represents the filter for the purpose of experimentation. Filter permeability is simulated by opening and

closing the valve.

– Read pump pressure from the pressure gauge.

– Observe the volumetric flow rate at the sight glass in the flow meter.

Resistance (degree of valve opening) and pressure

Degree of valve opening as percentage, V 103

pe [bar] Q [l/min.]

Open 0.18

80% 0.32

60% 0.3

40% 0.26

20% 0.22

Closed 0.32




Task

– Plot the pressure measured in the piping system relative to the degree of valve opening on the graph:

– How are pressure and volumetric flow rate within a piping system influenced when resistance within the

piping system is continuously increased?

As the stopcock is gradually closed, pump delivery pressure increases proportional to the valve setting.

The volumetric flow rate within the piping system drops at the same rate.

– Why doesn’t pressure continue to rise after the stopcock has been fully closed?

Because the impeller pump is incapable of generating high levels of pressure due to its design.

– Explain how an impeller pump works.

The pump has a rotating impeller. The liquid is accelerated in a circular movement and is fed radially to

the outlet. The pump functions hydro-dynamically.



– Why is it important to ensure that there’s no air in the pump?

Air in the pump would prevent the liquid from being pumped into the piping system.

Not enough delivery pressure is built up in order to pump the liquid upwards.

If cavitation occurs, the pump may be damaged.

– Which types of pumps can be used in the field of process technology? Use information from various

manufacturers in order to research your answer. Create a table with typical characteristics, as well as

technical data and the range of applications, for a given type of pump.


Impeller pump

Impeller pumps are the most commonly used type of pump in

process engineering systems. Principle: an impeller equipped

with blades rotates at high speed in a spiral shaped pump casing.

As a rule, the impeller is driven by an electric motor. The liquid to

be delivered enters the pump casing through the intake nozzle

which is aligned to the rotary axis. It’s accelerated radially by the

impeller and is discharged from the pump casing through the

discharge nozzle. Impeller pumps are capable of relatively large

delivery rates with small to moderate total head. Viscous liquids

and media which contain solids can be delivered with the help of

specially designed impellers.

Piston pump

The main components of the piston pump include a displacement

piston, as well as intake and discharge valves which open and

close automatically.

During the intake stroke, the discharge valve is closed, the piston

generates underpressure and the medium to be delivered is

drawn into the pumping chamber via the open intake valve.

During the discharge stroke the piston presses the medium

through the open discharge valve and out of the pumping

chamber (the intake valve is closed).

The delivery line is equipped with an air cushion chamber in order

to equalise the resulting pressure surges.

Discharge pressure is determined by the force which is required

to open the discharge valve. In the case of adjustable discharge

valves with spring return, discharge pressure can be adjusted

with the discharge valve itself (spring preloading).




Peristaltic pump

With the peristaltic pump, only the pipe comes into contact with

the medium to be delivered. Peristaltic pumps are used to deliver

and dose aggressive media at low output rates.

Progressive cavity pump

Progressive cavity pumps are suitable for delivering sludge and

paste-like media.

Diaphragm pump

Diaphragm pumps use a diaphragm in order to displace the

medium to be delivered. Only the diaphragm and the pump

casing come into contact with the medium. Diaphragm pumps are

especially well suited for delivering aggressive media.



1.2 Project task: mixing system


Information

The ingredients fed to a mixing system are usually required in the defined quantity. Mixing systems of this

sort are used, for example, to mix cement. A corresponding amount of water must be fed to the cement

mixer in order to produce a specified concrete mix. The quantity is time-controlled. A prerequisite is that a

constant volumetric flow rate must be maintained, e.g. 60 litres per hour.

The relationships between resistance (degree of stopcock opening), the delivered amount of water and the

required amount of time can be determined by means of an experiment. Run the experiment using the

existing test setup with one tank.



1.2.2 Experiment: flow measurement

The relationships between resistance (degree of stopcock opening) and volumetric flow rate, as well as the

amount of water delivered within a specific period of time will be examined. In doing so, we’ll look into the

question of how long it takes to pump 2 litres of water into the upper tank with various degrees of opening

at stopcock V103.

Task

– Read the volumetric flow rate at the sight glass in the flow meter.

– Set volumetric flow rate to the required flow rate.

– Fill the upper tank.

– Measure the time it takes for the water level to rise from the 0.5 to the 2.5 litre mark.

– Enter measured time in the table.

Q [l/hr.] Time [s]

400 18

300 24

200 40

100 70

60 110

40 160

Volumetric flow rate per unit of time




Task

– Plot the measured time values and the volumetric flow rate settings on the graph.

– Describe your observations on the experiment in a few short sentences:

The delivered quantity of water depends on flow rate and duration.

The greater the resistance in the piping system is (stopcock closed), the smaller the volumetric flow rate

becomes.

– How long would it take to pump 150 litres of water if the flow rate were set to 90 litres per hour?

Time for 90 litres: 1 hour; time for 1 litre: 0.67 minutes

For 150 litres: t = 150 litres x 0.67 min. per litre = 100 minutes

1 hour and 40 minutes are required for 150 litres.

– It takes 0.033 hours to fill the tank to the 2 litre mark. Calculate the volumetric flow rate for any desired

setting for stopcock V101 with the help of the measured time value. Check the selected volumetric flow

rate against the results of your calculation.

2 minutes = 0.033 hours

h/l60h033.0

l2tV

Q ===



2.1 Project task: controlling water supply using hand valves

Water storage tank


Information

Water is pumped into a water tower from springs, rivers and lakes in order to supply households with

drinking water. Water is directed to domestic households from the tower. The upper tank will be filled with

water during the course of two experiments. There are two ways to fill a tank: either from above or below.

The influence of these two methods on the filling process needs to be examined.



2.1.2 Mechanical layout



Task

Modification according to the PI flow diagram

– Supplement the PI flow diagram with a second tank as shown in the photo on the preceding page.

– Set up the basic layout with two tanks according to the revised PI flow diagram.

M

P101

V102

PI103

FI101

B102

V103

B101

V105

V101




Work step Done

The basic setup with two tanks is required in order to conduct the experiments.



Inspect the piping connections.


Connect the system to the power supply units (24 V DC).

Experiment: fill the upper tank from below.


Experiment: fill the upper tank from above.




2.1.4 Experiment: filling the upper tank from below

Task


– Measure the time it takes to reach various fill levels as of 500 ml (first mark after the taper).

– Observe pump pressure at the pressure gauge.




600 4 1400 48 2200 93

700 11 1500 53 2300 98

800 15 1600 59 2400 104

900 20 1700 65 2500 110

1000 26 1800 70 2600 116

1100 31 1900 75 2700 122

1200 37 2000 81 2800 127

1300 42 2100 87 2900 –

Fill levels: filled from below

2.1.5 Experiment: filling the upper tank from above

Task


– Measure the time it takes to reach various fill levels as of 500 ml. Observe pump pressure at the

pressure gauge.


600 5 1400 46 2200 87

700 10 1500 51 2300 92

800 14 1600 56 2400 97

900 19 1700 61 2500 102

1000 25 1800 66 2600 107

1100 30 1900 72 2700 112

1200 35 2000 77 2800 118

1300 40 2100 81 2900 –

Fill levels: filled from above




Task

– Which fundamental influence does hydrostatic pressure have on pump performance?

If a pump delivers water in an upwards direction within a piping system, hydrostatic pressure within the

piping system increases proportional to total head. This counterpressure generates resistance in the

piping system. The greater the resistance, the more electrical power is consumed by the pump.

– Copy the measured values for filling from below and from above onto a diagram. Create a worksheet in

Excel with the measured values and the two line diagrams.

– However, filling from below takes longer than filling from above. What causes this?

The liquid flows into the tank in the form of a whirlpool due to its conical shape. The water in the tank

represents an increasing resistance against the continuing flow of further liquid. The required energy is

made available by reducing pressure. As a result, the system’s volumetric flow rate drops. Furthermore,

hydrostatic pressure in the piping system increases as the tank is increasingly filled. This acts like

resistance in the piping system and thus reduces volumetric flow rate.



– What effects can be observed at the surface of the water and with regard to turbulence during the two

filling processes?

Air bubbles and noise can be observed when filled from above.

The liquid absorbs more air. In addition, reading the fill levels on the wall of the tank becomes difficult.

Significantly fewer bubbles occur when filled from below. Turbulence in the water is considerably

reduced as the fill level increases.

– Explain the relationship between the discharge rate and total head when an impeller pump is used.

As total head increases, more and more pump pressure is required. With unchanging hydraulic

performance due to constant electrical power, the discharge rate (volumetric flow rate) is reduced.

– Calculate the pump’s total head. Refer to the data sheet on CD-ROM for technical data.

m06.3

m

kg1000

s

m81.9

sm

kg000,30

h

sm

kg000,30Pa000,30bar3.0p

gp

h

hgp

32

2

2e

e

e

=×

×=

×===

r×=

×r×=



2.2 Project task: controlling water supply using 2-way ball valve

Information

Process valves with pneumatic actuators are used more and more frequently in modern process engineering

because they offer a host of advantages compared with electric and hydraulic actuators. Pneumatic

actuators are easier to handle and they’re very sturdy and economical. They’re exceptionally well suited for

use in potentially explosive atmospheres. Please refer to Festo’s marketing manual, “ABC of Process

Automation”, for further information.

1: Pump 2: Water storage tower 3: End users

Operating principle


Information

When filling the upper tank, the volumetric flow rate can be changed by opening or closing stopcock V101 or

V103. The filling process and the control of the volumetric flow rate will now be partially automated by

means of a pneumatically actuated 2-way ball valve.

The upper tank is filled from above via the ball valve. Stopcock V102 for lower tank B101 is partially open

(20%).



2.2.2 Mechanical layout, inspection

Task


– The ball valve is installed parallel to stopcock V101 as a bypass. The valve is mounted onto the

rectangular profile and then connected to the piping system. The ball valve is opened and closed using

a pneumatic actuator. The regulating unit consists of a brass ball valve (2) with semi-rotary actuator (4),

a flange-mounted NAMUR valve (1) with solenoid coil (3) and a sensor box (5). The sensor box is used

for electro-mechanical position signalling to the control and regulating unit with visual display for the

user.

– Take into account addition information included in the data sheets on CD-ROM.

– Modify the piping layout so that the ball valve is correctly fitted.

– Check to make sure that all of the piping connectors are properly fitted.

– Check the piping connections to the impeller pump.

– Inspect the mechanical setup and create a test report (see CD-ROM).



2.2.3 Plans

Task

– Supplement the PI flow diagram for pneumatic control.

M

P101

V102

PI103

FI101

B102

V103

B101

V105

V101V104



Pneumatic circuit diagram

– Draw the pneumatic circuit diagram for the 5/2-way solenoid valve (1V1) with spring return and the

semi-rotary actuator (1A1).

4 2

315

1A1

1V1

0Z1

– What requires special attention when connecting the three components, namely solenoid valve, semi-

rotary actuator and ball valve?

The 5/2-way solenoid valve with spring return controls the position of the semi-rotary actuator. The ball

valve is opened and closed by the semi-rotary actuator. When connecting the start and stop switches,

ensure that they cause the ball valve to open and close respectively. The initial position of the semi-

rotary actuator is plainly defined by the spring return.

Electro-pneumatic circuit diagrams

– Which possibilities exist for actuating the solenoid valve electrically?

Variant 1: direct connection via detented control switch

Variant 2: indirect connection via control switch and relay

Variant 3: indirect connection with start and stop pushbuttons and relay



– Draw circuit diagrams for the three possible means of actuation. Make a decision in favour of one

circuit. Mount the components onto the profile rail and wire the circuit. Explain your decision.

24 V

0 V

S4

P11M1

24 V

0 V

S4 K1 K1

P11M1K1

Variant 1 Variant 2

24 V

0 V

K1 K1S5 K1

S6

P11M1K1

1

234

2 3 4

S5 “START” S6 “STOP”

Variant 3



2.2.4 Commissioning, report

Task

The pneumatic components, the ball valve and the functions of all utilised mechanical and electrical

components such as switches, pushbuttons and impeller pump can now be commissioned and inspected.

The system is filled with water so that the pump is prevented from running dry. The water is pumped back to

the lower tank via the ball valve.

– Make a list of all of the characteristics and requirements for which the components have to be inspected

in the commissioning report. Tick the appropriate field after completing each inspection.




Indicator light and pump wired, cable binders

Ball valve mounted to semi-rotary actuator and solenoid valve

Check pneumatic connection of the solenoid valve and the semi-rotary actuator

Connect the solenoid valve to the control switch/relay (variants 1 and 2).

Connect the solenoid valve to the pushbuttons (variant 3).



up.

Set control switch to “Pump on”, press the start pushbutton, the indicator light

switches on and the pump runs.

Variants 1 and 2: set control switch to “Open ball valve”, water flows into the tank.

Set control switch to “Close ball valve”, water stops flowing into the tank.

Variant 3: press “Open ball valve” pushbutton, water flows into the tank.

Press “Close ball valve” pushbutton, water stops flowing into the tank.


running.

Set control switch to “Pump off”, the indicator light goes out and the pump stops

running.

Inspector Date

Commissioning report



2.2.5 Experiment: filling using a pneumatically controlled 2-way ball valve

Task

– Fill the lower tank manually with 3 litres of fresh water.

– Connect the system to the power supply unit (24 V DC).

– Open the ball valve and stopcock V102 (approx. 20%). Switch the pump on.

– Control the filling process by opening and closing the ball valve. Decide on a specific fill level, for

example 2 litres, to which the upper tank should be filled. Switch the pump off upon when the fill level

has been reached and drain back down to 1 litre. Repeat the filling process.

– Determine the volumetric flow rate by measuring how long it takes to reach a fill level of 2 litres. Close

stopcock V102 to this end.

– Compare the filling process using the ball valve with the one using stopcock V101.


Task

– Which advantages does the semi-rotary actuator offer in comparison with adjustment by means of a

stopcock?

The semi-rotary actuator responds more quickly than manual adjustment. The switch for actuating the

semi-rotary actuator can be mounted at an external location, allowing for easy observation of the fill

level. Volumetric flow rate through the ball valve is greater due to its larger cross section. The electrical

solenoid valve makes it possible to intervene in the process with the help of an automated controller.

– Which difficulties are experienced when trying to maintain a specific fill level?

The person who operates the semi-rotary actuator is required to compare the target value with the actual

value. However, human reactions, and thus the process, are delayed. The target value is therefore often

exceeded or fallen short of. The “human system” reacts sluggishly within the control circuit.



2.3 Project task: electrical control of the pump in the water supply line


Information

Filling the water tower is closely associated with water being withdrawn by one or more households. This issue

can be clarified with the help of two experiments. In addition, control of the system should also be expanded

electrically. Wiring of the electrical components will be adapted in line with the task at hand.

The first experiment addresses the question of how the fill level of the upper tank can be kept constant

when varying amounts of water are withdrawn.

During the second experiment we’ll operate the pump with variable voltage values and clarify the

relationship between voltage, amperage and volumetric flow rate. Costs incurred during operation of the

system will also be ascertained.


The system will be operated using the basic setup with two tanks. There’s no need to remove the pneumatic

process actuator, although it’s not required for the experiment.

Work step Done






1st experiment: fill the upper tank from below.

Close stopcock V101, open stopcock V103 such that an initial flow rate of 60 litres per hour is indicated at

the flow meter.

2nd experiment: fill the tank using variable voltages for the pump.

Fill the upper tank from below, close stopcock V101, open stopcock V103 so that the flow meter indicates

60 litres per hour.





2.3.3 Relay circuit with pushbuttons

Information

The system will be expanded electrically. The detented switch will now serve as a mains switch. The

indicator light will still indicate the operating state.

The system will be started by pressing a green pushbutton and stopped by pressing a red pushbutton.

Briefly pressing the respective pushbutton is enough to start or stop the system.

Task

– Which type of circuit has to be set up when pushbuttons are used? Which additional component is

required?

A self-latching electrical circuit, because the pushbutton only generates a short pulse. A relay is used,

which closes the electrical circuit until it is interrupted.

– Why do machines have to be controlled with a self-latching circuit instead of being operated with

switches?

In actual practice, an on/off switch is impermissible because for safety reasons the system would have to

be protected against being restarted after a power failure or in the event of power interruption due to an

emergency stop. The system can only be restarted by activating a pushbutton.




Task

– The system has to be rewired for the following experiments. Draw the expanded circuit diagram with

two pushbuttons, a detented mains switch and an indicator light. Identify the components.

0 V

K1S2 K1

S3

K1

P1K1

24 V

S1

MP101

234

2 3 4

1

– Add the connecting cables to the image with the electrical components to indicate how they have to be

wired according to the circuit diagram.



2.3.5 Electrical wiring and setup plan

Task

– The system will need to be rewired for the following experiments. Assemble the electrical components.

They can be prewired before they’re mechanically attached to the profile. Proceed according to your

layout sketch and the setup plan you prepared in the “Planning” section of the chapter on “Plant

construction”. Base yourself on the circuit diagram with regard to wiring.

– Write down your assembly and wiring procedures. Fill out the following setup plan after you have

mounted and wired the components.

See part D1 – Plant construction with solutions, chapter 2.3.3



2.3.6 Commissioning, electrical testing and report

Information

The new circuit with the pushbuttons and the functions of the existing electrical components, such as the

impeller pump, must now be started up and inspected. This is done by filling the system with water so that

the pump is prevented from running dry. The water is simply pumped around in a circular movement, i.e. out

of the bottom tank via the impeller pump and back into the lower tank from the upper tank.

Task

– Make a list of all the characteristics and requirements for which the electrical components have to be

inspected in the commissioning report. Tick the appropriate entry after completing each inspection.





Pump wired

Cables secured with cable binders



up.




running.



Set control switch to “Off”, the indicator light switches off and the pump stops

running.

Set control switch to “Off”, press the start pushbutton, the indicator light switches

off and the pump stops running.

Power supply unit “Off”, system is shut down

Inspector Date



2.3.7 Experiment: filling while simultaneously withdrawing water

The upper tank needs to be filled from below with a constant volumetric flow rate. Stopcock V101 is closed,

stopcock V103 simulates resistance in the system by being opened. It’s opened until the water flows into

the upper tank at a volumetric flow rate of 60 litres per hour. At the same time, the stopcock for discharge to

the user is open (approx. 20%).

– Measure the time it takes to fill the upper tank. Add the values to the table.


600 23 1400 320 2200 –

700 52 1500 395 2300 –

800 78 1600 490 2400 –

900 107 1700 620 2500 –

1000 140 1800 – 2600 –

1100 175 1900 – 2700 –

1200 215 2000 – 2800 –

1300 265 2100 – 2900 –

Filling with open discharge




Task

– Create a line diagram for fill level relative to time.

– What does the curve tell you?

Pressure rises as the fill level increases, and volumetric flow rate is reduced. As the fill level increases,

the amount of discharged water increases until an equilibrium is established between intake and

discharge.

– What’s meant by the term self-latching circuit?

The electrical circuit is closed by means of a normally open contact in the relay and can only be

interrupted by activating the normally closed contact in the parallel current path. Restarting is only

possible with the start pushbutton.



2.3.9 Experiment: pump start-up performance and power

The water level in the upper tank can be kept constant while water is withdrawn by changing the volumetric

flow rate. Volumetric flow rate will be influenced in this experiment by changing electrical voltage at the

power supply unit. You’ll need a power supply unit with variable output voltage for this experiment.

We’ll fill tank B102 with water from below. Stopcock V101 is closed. Stopcock V103 is opened to such an

extent that a volumetric flow rate of max. 400 litres per hour is achieved with 24 V DC. Stopcock V102 is only

partially opened (approx. 20%).

Task

– What are the volumetric flow rates when the pump is operated with various voltages ranging from 24 to

0 V DC?

– How does current consumption at the impeller pump change?

– Record the measured values and add them to the table.

Voltage U [V] Current I [A]

Electrical power P [W] = U · I

Volumetric flow rate Q [l/h]

Pressure pe [bar]

Hydraulic power P [W] = pe · Q

24 0.66 15.8 400 0.26 2.9

22 0.58 12.8 360 0.24 2.4

20 0.52 10.4 330 0.2 1.8

18 0.47 8.5 300 0.17 1.4

16 0.41 6.6 260 0.14 1.0

14 0.37 5.2 200 0.12 0.7

12 0.3 3.6 150 0.1 0.4

10 0.26 2.6 80 0.08 0.2

8 0.23 1.8 <40 0.06 < 0.1

Filling using varying pump voltages




Task

– Draw a circuit diagram with a voltmeter and an ammeter.

24 V

0 V

A

MP101 P1V

– Create a diagram with two curves, one for volumetric flow rate Q and the other for electrical current I

relative to voltage U.

– What do the curves tell you about the pump’s start-up characteristics?

The pump doesn’t start until a voltage of approximately 8 V is reached. Friction in the pump is too great

for it to run with smaller voltages.



– What is the relationship between the three parameters current, voltage and volumetric flow rate?

When voltage is increased, volumetric flow rate rises. When volumetric flow rate is increased, electrical

current rises as well. The pump doesn’t start delivering water until a voltage of approximately 9 to 10 V is

achieved.

– Calculate electrical and hydraulic power, as well as efficiency, for a volumetric flow rate of 200 litres per

hour.

26.0W4.6W67.1

P

P

W67.1dm10dm

mcm100

cm

N3

s60min60mindm

200bar3.0h/l200pQP

W4.6A4.0V16IUP

elektr

.hydr

2

2

2

3

e.hydr

elektr

===h

=×

×××

××

=×=×=

=×=×=

– What is the relationship between the impeller pump’s current consumption and its output performance?

Volumetric flow rate must be increased in order to increase pump performance. Amperage rises because

electrical power has to be increased.

– How high are the electrical power costs when the pump is operated 8 hours a day for one month (30 days)

with a volumetric flow rate Q of 200 litres per hour? The cost of electrical power is roughly €0.17 per kWh.

Costs for 1 month = €0.17 per kWh x 0.0064 kW x 8 hours x 30 days = €0.261



3.1 From a control loop system to a control circuit

Information

Our fill-level system includes open and closed-loop control processes. How they differ will become clear

when we consider their respective characteristics.

Every process has an input quantity and an output quantity. For example, if we switch on the power supply

unit which supplies electrical power to the impeller pump, electrical current (input quantity) flows and the

pump begins to rotate and deliver water (output quantity). The input quantity affects the output quantity.

Open-loop control

However, if the output quantity is not fed back to the input as a signal so that, for example, the power

supply unit is switched off when the tank is full, we speak of an open-loop control process. In the case of

open-loop control, a process is started and stopped without periodically comparing and changing the

variables to be controlled.

Closed-loop control

If we want to regulate the filling process with a closed-loop control process, we need to continuously record

the fill level, for example via observation or a sensor and continuously compare the current fill level (actual

value) with the desired fill level (target value). Whenever deviation from the target value is detected, an

attempt is made to match the controlled variable (actual value) to the reference variable (target value) by

means of appropriate control measures. This type of control has a closed control path, also known as control

circuit.

Comparison of a human being as a controller and automated control using fill level monitoring as an

example:

Human being as a controller Automated control

Specified value Setpoints

Observation Actual value detection (ultrasonic sensor)

Make note of value Archive

Open or close valve manually Transmit electrical manipulated variable to valve

or pump

Regulator optimisation



Basic terminology for closed-loop control technology

Controlled variable x

The quantity to be controlled is designated controlled variable x. In our example this is the fill level or the

volumetric flow rate.


Automated closed-loop control is only possible if the system can be manipulated and the controlled variable

influenced. The extent to which the controlled variable can be influenced is manipulated variable y. In the

case of closed-loop control of a fill level, the manipulated variable is the degree to which the stopcock is

opened, and in the case of closed-loop control of the volumetric flow rate, it’s electrical current at the pump.

Reference variable w

Reference variable w is also known as the controlled variable setpoint. It specifies the desired value of the

controlled variable. The reference variable may remain constant over time, but it may also change. The real

value of the controlled variable is called the actual value.


All controlled systems are subject to disturbance. These are often the only reason that closed-loop control is

necessary at all.

In our example, the stopcock for discharge to the consumer is opened and the fill level changes or the valve

setting for filling the upper tank is changed which results in a change to the volumetric flow rate. These

interfering influences are designated disturbance variable z.

The controlled system is the part of the overall setup within which the controlled variable must be matched

with the value of the reference variable. The controlled system can be represented as a system with the

controlled variable as the output quantity and the manipulated variable as the input quantity.

System deviation xd

The difference between the reference variable and the controlled variable is called system deviation xd or e.

This difference is calculated as follows: e = w - x

Closed-loop controller

It is the task of the closed-loop controller to keep the controlled variable as close as possible to the

reference variable. The value of the controlled variable is continuously compared with the reference variable

by the closed-loop controller. The value of the manipulated variable is calculated on the basis of this

comparison, as well as control response, and is read out.

Controlled variable xActual value

Manipulated variable ySystem deviation xd

Reference variable wSetpoint

( )Control responseAlgorithm

+

Basic function of a regulator



Control circuit

The control circuit contains all the components of the closed loop that are required for automated closed-

loop control.

Controlled system

Controlled variable xActual value( )

Controller Reference variable wSetpoint( )


Block diagram of a control circuit

Controlled system

The controlled system is the part of the machine or system within which the controlled variable is to be

matched to the specified value and the disturbance variables are offset by the manipulated variables. The

manipulated variable is not the controlled system’s only input quantity; interfering influences also occur as

input variables.

In order to select a closed-loop controller for a controlled system, the performance of the controlled system

must first be known. The control technician is not interested in the technical sequences which take place

within the controlled system, but only in system performance.

3.2 Project task: controlling the fill level in the tanks



to clarify how a specified fill level can be constantly maintained in the upper tank. Closed-loop control is

possible in different ways:

· Open and close stopcock V101 or V103.

· Switch the pump on and off.

· Change voltage supplied to the pump.

During the first experiment, “manually keeping the fill level constant in the upper tank”, we’ll attempt to

regulate the fill level by switching the pump on and off. We can supply the pump with voltages ranging from

0 to 24 V using the power supply unit. The pump is switched on and off with the pushbuttons. Observe the

control process.

During the second experiment, “controlling the fill level using an analogue controlled pump”, we’ll operate

the pump with variable voltage ranging from 0 to 24 V DC, and thus control the volumetric flow rate and

influence the tank’s fill level within a certain period of time. You’ll need a power supply unit with adjustable

output voltage to this end.




Task


– Check to make sure that all piping connections are correct.

– Check to make sure that all electrical wiring connections are correct.

– Fill the lower tank with 3 litres of water.

– Connect the system to the respective power supply unit (max. 24 V DC).

– Carry out the experiment.

– Remove the 4 mm safety cable from the power supply unit and pull the mains plug.

– After the experiment has been completed, the system is drained via stopcock V105.

3.2.3 Experiment: manually keeping the fill level constant in the upper tank

The upper tank should always have a constant level of water of 2000 ml. Varying quantities of water are

withdrawn via stopcock V102 and supplied to a household (lower tank B101).

Task

– Switch the pump on and off with the pushbutton so that the fill level remains constant.




Task

Enter the following control technology terms to the block diagram of the system: actual value x, setpoint w,

manipulated variable y, switching difference sd, disturbance variable z, closed-loop controller, controlled

system.

M

P101

V102

PI103

FI101

B102

V103

B101

V105

V101x

wController

y

Reference variable wSetpoint, fill-level

Controlled variable xActual value, fill-level

Manipulated variable yVoltage

( )

( )

( )


Sd

Controlled system

– A fill level of 2100 ml is established as an upper limit and 1900 ml is the lower limit. This results in a

switching difference sd of 200 ml.

Why are these limit values specified?

In the case of manual control, the respective setpoints are usually only achieved with a certain amount of

delay. In order to provide the “closed-loop controller” with a certain amount of leeway, a switching

difference is established within which the control process functions well.



– Establish the inequality for switching the pump on and off. Inequality is meant here as the “greater” or

“smaller” relation amongst the actual value, the setpoint and the switching difference.

Pump on: actual value < setpoint - switching difference / 2

Pump off: actual value > setpoint + switching difference / 2

– Represent the filling process graphically as a line diagram. Plot the fill level on the ordinate (Y-axis) and

time on the abscissa (X-axis).

– What do we call this type of control? In which types of devices do closed-loop controllers operate on the

basis of this principle? Provide several examples.

Two-step control

Iron, stove, hardening furnace etc.

– Which features characterise this type of control?

There are only two states with two-step control: signal “on” and signal “off”, i.e. the electrical circuit is

closed or open. This type of control is also known as discontinuous control. It is very difficult to keep the

setpoint constant. A switching difference (tolerance) is required in order to be able to manage the control

process.



3.2.5 Experiment: controlling the fill level using an analogue controlled pump

Once again, the tank should be filled to a constant level of water of 2000 ml. Varying quantities of water are

withdrawn via stopcock V102 and supplied to a household (lower tank B101). The volumetric flow rate is

influenced by changing speed, thus enabling the system to react to irregular withdrawals of fresh water from

upper tank B102.

– Vary the pump speed by increasing and decreasing voltage supplied by the power supply unit and

observe the volumetric flow rate.


Task

– Allocate the terms and characteristics from the description of the experiment to the control technology

terms.

Controlled variable: volumetric flow rate Manipulated variable: electrical voltage

Reference variable: 2000 ml fill level Disturbance variable: stopcock V102

– First of all, fill the upper tank from above with stopcock V102 fully closed. Then open stopcock V102

according to the specifications in the table and describe what you observe while controlling the process.

React to changes in the fill level by varying the power output voltage.

Stopcock V102 Control process, observations

Closed Control is not possible.

10% open It takes a long time for the control process to change a higher fill level down to a lower level.

50% open The fill level can be controlled effectively with voltage values within a range of 10 to 14 V.

100% open Excessive turbulence, neither fill level nor good flow rate are achieved because there’s too much air in the

system.

Test report

– Why is this also known as continuous control?

The controlled variable is controlled by means of the manipulated variable, namely voltage. This is done

continuously. When continuous controllers are involved, manipulated variable y is read out as an

analogue signal so that it can be adapted to the process in an infinitely variable manner.



– Create a graphic representation of the closed-loop control process. Draw a graph which shows the fill

level over a period of time as a strictly qualitative characteristic.

3.2.7 Experiment: pressure and flow control

Separately conduct pressure control and flow rate control, also known as volumetric flow rate control. Control

pressure and volumetric flow rate by varying the output voltage of the power supply unit between 0 and 24 V DC.

Set up the circuit according to the PI flow diagrams.

Pressure control

M

P101

PI103

V103

B101

V105



Flow rate control

M

P101

V103

B101

V105

FI101


Task

– Determine the manipulated variable required for maintaining constant pressure, as well as for

maintaining constant volumetric flow rate, with varying resistance (stopcock V103).

Target pressure (w) = 200 mbar

Target volumetric flow rate (w) = 100 l/hr.

– Add the voltage values for the various stopcock settings to the table. Conduct the experiment once with

constant pressure and once with constant volumetric flow rate.

– Mark the opening values of the stop cock on the rotary cap so that the experiment can be duplicated

exactly.

Setting for stopcock V 103

Pressure control, voltage U (y) where pe = 200 mbar (w)

Flow rate control, voltage U (y) where Q = 100 l/hr. (w)

Open

20% closed

40% closed

60% closed

40% closed

20% closed

Values table



– What is the relationship between the stopcock setting and pressure or volumetric flow rate?

Constant pressure:

The further the stopcock is opened, the less resistance there is and the higher the voltage (manipulated

variable) has to be set.

Constant volumetric flow rate:

The further the stopcock is opened, the less resistance there is, and the lower the voltage (manipulated

variable) has to be set.


4. Evaluation of learning objectives for manual measurement, open-loop and closed-loop control

1. How do pressure and volumetric flow rate of a liquid respond when resistance is increased in the inlet

line which feeds the tank?

Pressure rises and volumetric flow rate drops.

2. 70 litres of water have to be recirculated using a volumetric flow rate of 200 litres per hour. How long

does the pump have to work?

200 litres in 1 hour = 60 minutes

10 litres in 3 minutes

70 litres in 21 minutes

3. Which physical quantities determine hydrostatic pressure?

Hydrostatic pressure is the pressure in a liquid which is at rest. It depends on gravitational acceleration g,

density r and capillary rise h. Hydrostatic pressure increases as the water column rises.

4. Why does it take longer to fill the upper tank in our system from above than from below?

Hydrostatic pressure has nearly no effect at all at a minimal filling height. The fact that water flows into

the tapered portion of the tank from below in the form of a whirlpool causes resistance which further

increases as the fill level rises.

5. The filling nozzle at the top can be fitted at a level of, for example, 1.1 metres. How much pump

pressure would be required to reach this filling height?

Min. Pe: 0.11 bar

6. Describe how a self-latching circuit functions. Which components are required for such a circuit?

When a relay’s electrical circuit is closed (brief signal at the ON button), it’s maintained by means of a

normally open contact in the relay. The circuit is interrupted again by means of a normally closed contact

(OFF button).



7. The upper tank is continuously filled with water and a certain amount of water is discharged from the

tank. In a diagram, the process would be designated asymptotic, i.e. it approaches a specific value.

Sketch a graph which shows the fill level over a period of time as a qualitative characteristic.

8. Describe in your own words the procedures used for connecting an ammeter and a voltmeter in order to

record pump values.

The ammeter is connected to the current path upstream of the pump. The voltmeter is connected parallel

to the pump.

9. You’re working with variable voltage within a range of 0 to 24 V. How do volumetric flow rate and

amperage I change when voltage is reduced from 24 to 0 V.

When voltage is reduced, volumetric flow rate and amperage drop.

10. The maximal Pump efficiency is h = 0.26. What is the meaning of this value with regard to our

experimental system and which effects does efficiency have in actual practice?

In this case it means that usable pump power is about 25% of applied motor power. In actual practice it

must be determined whether or not the additional benefits offered by a pump which is not susceptible to

contamination outweigh achievable power. Of course an attempt is made in actual practice to artificially

boost efficiency.



11. Sketch a pneumatically actuated 5/2-way valve with spring return.

See Festo pneumatics data sheets.

12. Which fundamental advantages are offered by a 2-way ball valve with electro-pneumatically actuated

actuator as opposed to manual operation?

The valve can be opened by a controller.

13. Describe the terms “open-loop control” and “closed-loop control” using a radiant heater as an example.

Open-loop control:

Closed-loop control:

See “Control” in the Teachware for the solution.

14. How are manipulated variable y and controlled variable x related?

Manipulated variable y is a voltage value U used to vary pump speed. This changes volumetric flow rate

through the pump and thus the controlled variable, for example the fill level of the tank.

15. How does a two-step controller work?

A two-step controller switches back and forth between two adjustable limit values. The difference

between the upper and the lower limit values is known as the switching difference or system deviation.

16. Why is an excessively small switching difference disadvantageous?

A small switching difference causes the pump to be switched on and off very frequently and thus results

in rapid wear and tear (number of switching cycles).

17. What’s the fastest way to get the system adjusted to the setpoint?

By continuously adjusting the inlet valve or voltage at the pump.



18. What is the control process called with which the manipulated variable can be continuously varied?

Continuous control with analogue controlled, manipulated value.

19. Pressure needs to be kept constant within the fill-level system, even when the volumetric flow rate is

continuously increased. Which parameter must be changed within the system?

When resistance in the piping system drops, voltage supplied to the pump must be increased in order to

maintain constant pressure.

20. How can the volumetric flow rate within the fill-level system be kept constant, even though the pump

needs to be operated in an energy-saving fashion?

If the inlet valve is opened further, volumetric flow rate increases, pump voltage can be reduced and

power consumption is reduced.


Part D3 – Practice-based learning: automated measurement, open-loop and closed-loop control with solutions

1. Basic principles __________________________________________________________________ D3-3

1.1 Computer-aided control technology __________________________________________________ D3-3

1.2 System conversion for automated measurement and control technology ___________________ D3-5

2. Automated measurement _________________________________________________________ D3-13

2.1 Project task: bath recirculation _____________________________________________________ D3-13



2.1.3 Experiment: operating the pump with variable voltage values ___________________________ D3-17

2.2 Project task: pressure measurement during recirculation _______________________________ D3-17



2.2.3 Experiment: pressure measurement using a pressure sensor ____________________________ D3-20

2.3 Project task: flow measurement ____________________________________________________ D3-20



2.3.3 Experiment: flow measurement using a flow sensor ____________________________________ D3-21

2.4 Project task: determine the fill level of the upper tank __________________________________ D3-21



2.4.3 Experiment: measuring the fill level using an ultrasonic sensor __________________________ D3-23

3. Automated open-loop control ______________________________________________________ D3-25

3.1 Project task: filling process ________________________________________________________ D3-25



3.1.3 Experiment: metered filling via the pneumatic actuator _________________________________ D3-26

3.2 Project task: filtering process in a galvanising plant ____________________________________ D3-26



3.2.3 Experiment: determining pressure and volumetric flow rate _____________________________ D3-29

3.2.4 Experiment: creating a characteristic pump curve ______________________________________ D3-30

3.3 Project task: water supply _________________________________________________________ D3-33



3.3.3 Experiment: filling the tank from below using the pump ________________________________ D3-34

3.3.4 Experiment: filling the tank from above using the pump ________________________________ D3-35

3.3.5 Experiment: filling the tank from above while simultaneously withdrawing water ___________ D3-36

3.4 Project task: dosing an amount of liquid _____________________________________________ D3-37


3.4.2 Experiment: dosing an amount of liquid ______________________________________________ D3-38



4. Automated closed-loop control ____________________________________________________ D3-41

4.1 Project task: controlling the fill-level regulation using a two-step controller ________________ D3-43



4.1.4 Commissioning __________________________________________________________________ D3-45

4.1.5 Experiment: controlling the fill level using a two-step controller __________________________ D3-45

4.2 Project task: controlling the fill level using a continuous controller _______________________ D3-49


4.2.2 Experiment: controlling the fill level using a continuous controller ________________________ D3-50

4.2.3 Experiment: controlling the fill level using a proportional controller _______________________ D3-51

4.2.4 Experiment: controlling the fill level using an integral controller __________________________ D3-52

4.2.5 Experiment: controlling the fill level using a proportional-integral controller

(parallel P and I components) ______________________________________________________ D3-54

4.3 Project task: refrigerating plant _____________________________________________________ D3-56



4.3.3 Commissioning report ____________________________________________________________ D3-57

4.3.4 Experiment: flow control using a proportional-integral controller _________________________ D3-57

5. Evaluation of learning objectives for automated measurement, open-loop and

closed-loop control _______________________________________________________________ D3-59