Summer Internship Project Report

June 2014

Automatic FEEDING ,measuring temperature

& ejecting of components using plc

At

Central Institute of Tool & Design,Hyderabad

Under The Guidance of

Mr Babulal

Submitted by:-

Sai Shubhankar

Er no-A4717211003

7th sem

B.tech-Aerospace +M.tech-Avionics

Amity Institute of Space Scince & Technology

Noida,U.P.

CERTIFICATE

This is to certify that Mr SAI SHUBHANKAR DUAN,a student

of B.Tech. in AEROSPACE+M.Tech. AVIONICS(DUAL DEGREE) has

carried out the work in the project of the summer internship

entitle "automatic feeding,measuring temperature

and ejecting of component using plc" as a part of

Third year programme of B.Tech in AEROSPACE+M.Tech In

AVIONICS from Amity Institute of Space Science and Technology,

Amity University, Noida, Uttar Pradesh under my supervision.

Name & signature of the industry guide

Uday bhaskar reddy

DIRECTOR TRAINING

CENTRAL INSTITUTE OF TOOL AND DESIGN,

HYDERABAD

Acknowledgement

I would like to take this opportunity to thank and express my deep

sense of gratitude to my industry guide Mr Babulal,engineer

grade-III. I am greatly indebted to him for providing me his valuable

guidance at all stages of study ,his advice, constructive suggestion,

positive and supportive attitude and continuous encouragement

without which it would have not possible to complete the project.

I would like to thanks MR Krishna swamy(Director,CITD) who in

spite of busy schedule has co-operated continuously and indeed,his

valuable contribution and guidance have been certainly

indispensable for my project work.

I owe my wholehearted thanks and appreciation to entire staffs of

the company for their cooperation and assistance during the course

of my project.

I hope that I can build upon the experience and knowledge I have

gained and make a valuable contribution towards this industry in

coming future.

Abstract

Mechatronics is “the synergistic integration of Mechanical Engineering with Electronics

and intelligent control algorithms in the design and manufacture of products process”.

This subject is invented by Japanese engineer in1969.Mechatronics is used in the design

and manufacturing of products in large industries. Mechatronics is more than a control

systems.

Automation is a technology dealing with application of ‘mechatronics’ and computers

for production of goods and services. In the scope of industrialization ,it is a step beyond

mechanization. Whereas mechanization provides human operators with machinery to

assist them with the physical requirements of work ,automation greatly reduces human

sensory and mental requirements as well specialised hardened computers referred to

as “Programmable Logic Controllers”(PLC’s), are used to synchronized the flow of

inputs from sensors and events with the flow of outputs to the actuators and events.

This leads to precisely controlled actions the permit a tight control of any industrial

process.

Under the mechatronics the systems available are pneumatics, electro-pneumatics,

hydraulics, electro-hydraulics, programmable logic control(PLC).Pneumatics deals with

the systems which work on air pressure. Hydraulics deals with the systems involving

fluids. Electro pneumatics and electro hydraulic system deal electrical systems to

control pneumatic and hydraulic systems. PLC is the hardware which can be

programmed , to define the relationships among inputs given to PLC and outputs taken

from the PLC.

Purpose of pneumatics, electro-pneumatics, hydraulics, electro-hydraulics and PLC is

same i.e. to automate the production and manufacturing. But every system has its own

advantages and disadvantages. System is chosen depending the advantages that suits

the requirement.

The project “Automatic feeding, measuring temperature and ejecting of components

using PLC” is used to measuring temperature of various components. The project is

being explained in Programmable Logic Controller which form the control unit of this

project.

Depending upon the inputs received from the sensors, the programmable controller

generates required actuating signals for the cylinders that help in placing components

at a specified position.

For this purpose we use proximity sensors, PLC software, power supply, solenoid valves

caps and containers which are required for setup. As it LCA(Low Cost Automation) this

process of sorting may increase the speed and meet the requirements with less manual

labour.

TABLE OF CONTENTS

PART 1: Training on Mechatronics

CHAPTER 1 :AUTOMATION

1.1 Introduction

1.2 Types of Automation

1.3 Advantages of Automation

1.4 Disadvantages of Automation

CHAPTER 2 :PNUEMATICS

2.1 Introduction

2.2 Gases used in Pnuematic system

2.3 Pnuematic Logics

2.4 CETOP Symbols

2.5 Valves

2.6 Applications of pneumatics

2.7 Advantages of Pnuematics

2.8 Disadvantages of Pneumatics

CHAPTER 3 : ELECTRO-PNUEMATICS

3.1 Introduction

3.2 Types of valves in Electro-Pnuematics

3.3 Solenoid

3.4 Cylinder

3.5 Compressor

3.6 Ladder Diagram

3.7 Advantages of Electro-Pnuematics

3.8 Disadvantages of Electro-Pneumatics

CHAPTER 4 : SENSORS

4.1 Introduction

4.2 Sensor Performance

4.3 Classification of Measurement errors

4.4 Sensor Deviations

4.5 Types of Sensors

CHAPTER 5 : PROGRAMMABLE LOGIC CONTROLLERS

5.1 Introduction

5.2 Building block of PLC

5.3 Constituents of PLC

5.4 PLC Scan

5.5 How it differs from the Computers ?

5.6 Basic requirements

5.7 Programming a PLC

5.8 Program Structure

5.9 STEP 7 Programming

5.10 Advantages

5.11 Applications

PART 2 :

CHAPTER 6 : PROJECT

Automatic feeding, measuring temperature and ejecting of

components using PLC.

Bibliography & reference :

Chapter 1

Automation

1.1 INTRODUCTION:

Definition: It is process of replicating human efforts through the application of machines.

The word ―AUTOMATION‖ derived from the Greek words ―AUTO‖ and ―MATOS‖

means self -acting.

It is the technology dealing with the application of mechatronics and computers for

production of good and services.

The biggest benefit of automation is that it saves labour, however, it is also used to save

energy and materials and to improve quality, accuracy and precision.

Automation has been achieved by various means including mechanical, hydraulic,

pneumatic, electrical, electronic and computers, usually in combination. Complicated

systems, such as modern factories, airplanes and ships typically use all these combined

techniques.

Automation Technology Includes:-

Automation machine tools to process plans

Automation assembly machines

Industrial Robotics

Automation material handling and storage system etc.

MAIN COMPONENTS OF AUTOMATION:

1.ACTUATORS :- An actuator is a type of motor for moving or

controlling a mechanism or system. It is operated by a source of energy, typically

electric current, hydraulic fluid pressure or pneumatic pressure , and converts that

energy into motion.

2.CONTROLLERS :- Controllers are those components which take signals

from sensors and control the motion of the actuator.

3.SENSORS :- A sensor is a converter that measures a physical quantity

and converts it into a signal which can be read by an observer or by an instrument.

Every automated system has these 3 components. CETOP symbols are used to

denote or represent correctly the actuators and mainly controllers.

1.2 TYPES OF AUTOMATION:

Automation based on production is classified into 3 basic types:

1.Fixed Automation (Hard Automation)

2.Programmable Automation (Soft Automation)

3.Flexible Automation

1.2.1 FIXED AUTOMATION:

Fixed automation refers to the use of special purpose equipment to automate a

fixed sequence of processing or assembly operations. Each of the operation in the

sequence is usually simple, involving perhaps a plain linear or rotational motion

or an uncomplicated combination of two. It is relatively difficult to accomodate

changes in the product design. This is called hard automation.

Advantages:

1. Low Unit cost

2. Automated material handling

3. High production rate

Disadvantages :

1. High intial Investment

2. Relatively inflexible in accommodating product changes.

1.2.2 PROGRAMMABLE AUTOMATION :

In programmable automation, the production equipment is designed with the capability

to change the sequence of operations to accomodate different product configurations.

The operation sequence is controlled by a program, which is a set of instructions coded.

So that they can be read and interpreted by the system. New programs can be prepared

and entered into the equipment to produce new products. Examples: Numerical

controlled machine tools, industrial robots and programmable logic controller

Advantages :

1. Flexible to deal with design variations.

2. Suitable for batch production.

Disadvantages :

1. High investment in general purpose equipment.

2. Lower production rate than fixed automation.

Programmable automation can be further divided into 2 types according to the

investment required for the automation.

1. Low cost Automation 2. High cost Automation

1.2.3 FLEXIBLE AUTOMATION :

Flexible automation is an extension of programmable automation. A flexible

automation system is capable of producing a variety of parts with virtually no

time lost for changeovers from one part style to the next. There is no lost

production time while reprogramming the system and altering the physical set

up.

ADVANTAGES : 1. Continuous production of variable mixtures of product.

2. Flexible to deal with product design variation.

DISADVANTAGES : 1. Medium production rate

2. High investment

3. High ‘unit cost relative to fixed automation.

1.3 ADVANTAGES OF AUTOMATION :

Increased through output or productivity.

Improved quality or increased predictability of quality.

Improved robustness (consistency), of processes or product.

Increased consistency of output.

Reduced direct human labour costs and expenses.

1.4 DISADVANTAGES OF AUTOMATION:

Causing unemployment and poverty by replacing human labour.

Security Threats/Vulnerability

Unpredictable/excessive development costs

High initial cost

CHAPTER 2

PNUEMATICS

2.1 INTRODUCTION:

Pnuematics is a section of technology which deals with study and

application of pressurized gas to produce mechanical motion. Pnuematic

systems that are used extensively in industries and factories are commonly

plumbed with compressed air or compressed inert gases.This is because a

centrally located and electrically powered compressor, that powers cylinders

and other pnuematic devices through solenoid valves, can often provide motive

power in a cheaper,safer,more flexible and more reliable.

Pnumatics also has applications in density, mining etc.

2.2 GASES USED IN PNUEMATIC SYSTEM:

Pnuematic system in fixed installments such as factories used compressed

air because a sustainable supply can made by compressing atmospheric air. The

air usually has moisture removed and a small quantity of oil is added at the

compressor to prevent corrosion and lubricate mechanical components.

In portable pnuematic tools such as Robot War machine compressed

carbon dioxide is used.

2.3 PNUEMATIC LOGICS:

Pnuematic logic systems sometimes called as air logic control are often

used to control industrial processes, consisting of primary logic units such as:

AND logic

OR logic

Latching units

Timer units

Pnuematic logic is reliable and functional method for industrial purposes. Now

a days these systems are replaced by analog electronic or digital control system

in new installation because of the smaller size,lower cost, highly accurate, and

more powerful features of digital control.

Pnuematic system is an open system.

Operating pressure is 4 to 6 bars.

The basic principle behind the compression of air is "Boyle's law".

2.4 CETOP SYMBOLS: Comité Européen des Transmissions Oléohydrauliques et Pneumatiques is the

full form of CETOP.

CETOP represents more than 1000 companies- mainly some manufactures but

also some dealers with almost 70,000 employees and market value is about 13

billion EUROS.

2.4.1 Symbol:

Symbol consists of a line, letter, abbrevation which identify the purpose and

method of operation of the component representation.

1. Line:

a) Straight or direct line: Working line,pilot supply.

b) Dotted or dashed line: Pilot line or pilot control.

c) Chain line: Envelop/casing.

2. Letters:

A,B-working ports.

P-Pressure port

Z,Y-pilot port

R,S-Exhaust port

3. Numbers:

2,4-working ports

1-pressure port

12,14-pilot ports

3,5-Exhaust port

4. Abbrevation:

a)FLR: Filter Regulator Lubricator

b)DCV: Direction Control Valve

c)NRV: Non Return Valve

d)FCV: Flow Control Valve

2.5 VALVES:

A valve is a mechanism either to control the flow of gas or a mechanism

operated by a gas control to control the flow of some or other fluid.

A valve which requires pressurized air to operate open or close is known as

pnuematic valve.The valves in the pnuematics are referred as "Pilots".

2.5.1 TYPES OF VALVES:

In general valves are divided into 5 depending on the no of ports and

positions. 1)2/2 valve

2)3/2 valve

3)4/2 valve

4)4/3 valve

5)5/2 valve

2/2 valve:

A directional control valve with two ways,two ports and two positions.

Upper value represents the no of ports lower and lower value represents no

of positions.

3/2 valve:

A directional control valve with 3 ways ,3ports,2 positions.

Out of 3 ports we have

a)1 input

b)1 output or working port

c)1 exhaust

4/2 valve:

A directional control valve with 4 ways ,2 ports,2 positions.

Out of 4ports we have

a) 1 input(p)

b) 2 outputs or working ports(A,B)

c) 1 exhaust

4/3 valve:

A directional control valve with 4 ways,4 ports,3 positions.

5/2 valve:

A directional control valve with 5 ways, 5 ports and 2 positions.

Out of 5 ports we have:

a)1 input or pressure(p)

b)2 working ports(A,B)

c)2 exhausts(R,S)

2.5.2 AND & OR LOGICS VALVE:

AND logic:

It is a two pressure valve.

OR logic:

It have two inputs,parallel connections.

2.6 APPLICATIONS OF PNEUMATICS:

Industrial applications:

1)Clamping

2)Shifting

3)Positioning

4)Orientating

General applications:

1)Packing

2)Feeding

3)Door control

4)Metering

5)Transfer of materials

6)Sorting of parts

7)Stocking of components

8)Stamping or embossing of components

Machining and working operations:

1)Drillling

2)Turning

3)Milling

4)Measuring of components

2.7 ADVANTAGES:

The availability of air is more this is the main advantage.

Transportation is easy.

Less temperature fluctuations.

Components are relatively inexpensive.

More speed and accuracy.

Storage is easy and portable.

2.8 DISADVANTAGES:

It requires good preparation. Dirt and condensate shouldn’t be present.

Noise level is high .

Force requirement is more .

Compressed air is relatively expensive as conveying power.

CHAPTER 3

ELECTRO -PNUEMATICS

3.1 INTRODUCTION:

Electro-pnuematics is the control system of pipe organs where by air

pressure, controlled by electric current.The control of Pnuematics by electrical

impulses is known as Electro pnuematics.

This science is fast and expanding as it can make use of all electronic

development such as PLC'S and PC'S. However the electro pnuematics has

restrictions as it cannot be used in the places where electricity cannot be used

such as gas factories etc.

Here the actuator is pnuematic, controller is electric circuit.The solenoid are

used as inputs in this system.This works on the law of electro magnetic

induction.Many things can be done by using air pressure and remote control.

3.2 TYPES OF VALVES IN ELECTRO PNUEMATICS:

These are same as the pnuematic valves instead of pilots we use solenoids in

the electro pnumatics. 1. 2/2 valve

2. 3/2 valve

3. 4/2 valve

4. 5/2 valve.

In general we use 3/2 and 4/2 valves. For these valves we have normally

opened and normally closed positions depending up on the requirement.A 3/2

valve can be used as a push button valve or start button.

3.3 Solenoid:

A coil of wire that generates an electro magnetic force when a current is

applied.When activated,solenoids can open and close valves.There are two

types of operations of a electropnumatics: Single solenoid operation

Double solenoid operation

In electro pnumatics, the signal medium is electrical signal either AC or DC

source is used.

Working medium is compressed air.

Operating voltages are around 12V to 220V oftenly used.

The final control valve is activated by solenoid actuation.

The resetting of the valve is either by single solenoid or double solenoid.

Valves ,compressors and the cylinders plays a major role in the electro

pnuematics.

3.4 CYLINDER:

Electro pnuematic cylinders use air pressure differentials to produce force

and motion resulting in the work.

3.4.1 TYPES OF CYLINDERS:

Single acting cylinder

Double acting cylinder

Double rod cylinder

Diaphram cylinder

Rotary cylinder

Cushion cylinder

Tander cylinder

Telescopic cylinder

Plunger cylinder

Impact cylinder

Duplex cylinder

Cable cylinder

Rod cylinder

Muscle Cylinder

In general we use single acting and double acting cylinders. The rest of these

are used in the grinding mechanism, shoes manufacturing, garbage collecting,

pnuematic press, in buses for adjusting seats, automatic opening and closing the

doors in buses or malls etc..

5. Single acting cylinder:

It defined as a pneumatic actuator that directs energy in one direction.

a)It has only one opening and it acts as both the inlet and outlet depending

up on the situations.

b)It consists of a spring which is used for forward and backward movement of

the piston helps to return in the home position.

c)The single acting cylinder is controlled by one 3/2 valve.

Single acting cylinder is sub divided into

1)Spring to push

2)Spring to pull

Use: Used for clamping or holding purpose

6. Double acting cylinder:

It is defined as a pneumatic actuator that directs energy in two directions.

a)It has two ports one is inlet and the other is out let.

b)The double acting cylinder is controlled by two 3/2 valves.

c)When air sent though the in let the piston of the cylinder moves

forward, and when air is returned back the cylinder automatically moves in

reverse or back ward direction.

Use: Used for feeding purpose.

3.5 COMPRESSOR:

It is defined as a component that pressurizes the ambient air and directs into

a electro pneumatics.

3.5.1 TYPES:

Centrifugal type

Piston type

Gear type axial type

Pressure regulation type

Screw type.

3.6 LADDER DIAGRAM :

Ladder diagrams are specialized schematics commonly used to document

industrial control logic system .They are called "Ladder Diagrams" because they

resemble a ladder.

It has two vertical rails (Supply power) and as many "rugs"(horizontal

lines )as they are control units.

Ladder diagram includes

1)Coils

2)Timers

3)Monostable Vibrators.

—( )— :A regular coil energized when the rug is closed.

—(\)— : A "not"coil energized when rug is opened.

3.6.1 SYMBOLS:

3.6.2 Advantages of ladder diagram:

It is a simple graphical technique which is easy to understand.

Used in a part of documentation file.

Disadvantages of ladder diagram:

Complexity is more.

3.7 ADVANTAGES ELECTRO PNUEMATICS:

Better adaptability and flexibility.

Easy automation.

Temperature is flexible.

Higher reliability.

Lower planning and commissioning

Lower installation effort.

Simpler exchange information between several controllers.

Equipment cost is less compared to pnuematics.

3.8 DISADVANTAGES OF ELECTRO PNUEMATICS:

System use two supply units (pnuematic and electric).

Hazard of electrocution.

CHAPTER 4

SENSORS

4.1 INTRODUCTION: To be useful ,system must be interact with their environment.To do this they

use sensors and actuators.

Sensors and actuators are the examples of transducers.

A transducr is a device that converts one physical quantity into another.

Almost any physical property of a material that changes in a response to

some excitation can be used to produce a sensor.

-Widely used sensors includes those that are:

Inductive Sensors

Capacitive Sensors

Elastic Sensors

Thermal Sensors

Photoresistive Sensors

Piezoelectric Sensors

Thermal Sensors

4.2 SENSOR PERFORMANCE:

Range: Maximum and minimum values that can be measured. Resolution: Smallest indiscrinable change in measured values.

Errors: Difference between measured and critical values.

Accuracy,uncertainity,inaccuracy:Accuracy is a measure of

maximum expected error.

4.3 Classification of measurement errors: Is sensitive to measure the property only.

Is insensitive to the any other property likely to be encountered in its

application.

Does not influence the measured property.

Ideal sensors are to be linear to some simple mathematical function of

measurement, typically logarithmic. The output of such sensors is an analog

signal and linearly proportional to the value or simple function of the measured

property.

The sensitivity is then defined as the ratio between output signal and

measured property.

4.4 SENSOR DEVIATIONS: If sensor is not ideal several types of deviations are observed:

The sensitivity may in practice differ from the value specified. This is called

sensitivity error,but the sensor is still linear.

Noise is a random deviation of a signal that varies in time.

Hysterisis is an error caused by when the measured property is in reverse

direction, but there is some finite lag in the time for the sensor to respond,

creating a different offset error in one direction than in the other.

Long term drift usuallly indicates a slow degradation of sensor properties

over a long period of time.

If the sensor has a digital output,the output essentially an approximation of

measured property.The approximation error is also called as"Digitization

error".

CLASSIFICATION OF SENSORS: The sensors are classified into the following criteria:

Primary input quantity.

Transduction principles.

Materials and technology.

Property.

Applications.

4.5 TYPES OF SENSORS: Temperature sensors

IR sensor

UV sensor

Touch sensor

Proxmity sensor

1) Temperature Sensor: This device collects the information about the

temperature from a source and converts into the form that is understandable

by a person or a device. The outside temperature is source element for the

temperature measurement. The position of the mercury is observed by the

viewer to measure the temperature.

Temperature sensors are basically divided into two types:

a)Contact Sensor:This requires direct physical contact with object.

b)Noncontact Sensor: This does not require any physical contact.

Eg: Thermocouple, Resistant Temperature Detectors (RTD), Thermisters.

2) IR Sensor: This device emits AND/OR detects infrared radiation to

sense a particular phase in the environment.

Generally thermal radiation is emitted by all the objects in the infrared

spectrum.

Infrared Sensors detects the radiations which are not visible to the

human eye.

Advantages:

1)Easy for interfacing.

2)Readily available in the market.

Disadvantages:

Disturbed by the noises in the surroundings such as radiations,etc.

Applications:

*Thermography

*Heating

*Spectroscopy

*Meteorology

*Photo-biomodulation

*Climatology

*Communication

3) UV Sensor: These sensors measure the power or intensity of the

ultraviolet radiation. This form of electromagnetic radiation has longer wave

lengths compared to x-rays but still shorter than the visible radiation. UV

sensors discover the exposure environment to ultraviolet radiation.

Eg: ultraviolet light detectors, photo stability sensors.

Applications:

1)Measures the portion of UV spectrum which sunburns human skin.

2)Pharmacy

4)Robotics

4)Printing industry for solvent handiling and dyeing process.

5)Chemical industry for the storage,production and transportation.

4) Touch Sensors: Touch sensor acts as a variable resistor as per the

location where it is touched.

The touch sensor is made of:

*Fully conductive substance such as copper.

*Insulated spacing material such as foam or plastic.

*Partially conductive material.

Applications:

Commercial-Medical, vending, fitness and gaming.

Appliances-Oven, Refrigerators.

Transportation-Cockpit fabrication.

Industrial automation-Position and liquid level sensing.

Proximity Sensor:

A proximity sensor detects the presence of objects that are nearly placed

without any point of contact. Since there no contact between the sensor and

the sensed objects and lack of mechanical parts, these sensors have long

functional life and high reliablility.

Different types of proximity sensors are:

a)Inductive Proximity Sensors b)Capacitive Proximity Sensors c)Ultrasonic Proxmity Sensors Working: The proximity sensor emits an electromagnetic radiation

And waits for the return signal or changes in the field. The object which is

being sensed known as "Proximity Sensor's Target".

a) Inductive proximity sensors: They have an oscillator as input to

change the loss resistance by proximity of an electrically conductive

medium.These sensors are preferred for metal targets.

b) Capacitive Proximity Sensors: They convert the electrostatic

capacitance variation flanked by the detecting electrode and ground electrode.

This occurs by approaching the near by object with a variation in the oscillation

frequency.

c) Ultrasonic Sensors: These works on the principle similar to radars

which evaluate attributes of a target by interrupting the echoes from the radio or

sound waves respectively. These sensors generate high frequency sound waves.

Applications:

*Conveyor systems

*Roller coasters

*Parking Sensors

*Used in automation engineering

*Used in windows, the alarm is activated to when the window opens.

*Used in machine vibration monitoring.

CHAPTER 5

PROGRAMMABLE LOGIC CONTROLLER

5.1 INTRODUCTION

A Programmable Logic Controller, PLC or Programmable Controller is

a digital computer used for automation of electromechanical processes, such as control of

machinery on factory assembly lines, amusement rides, or light fixtures. PLCs are used in

many industries and machines. Unlike general-purpose computers, the PLC is designed for

multiple inputs and output arrangements, extended temperature ranges, immunity to electrical

noise, and resistance to vibration and impact. Programs to control machine operation are

typically stored in battery-backed-up or non-volatile memory. A PLC is an example of

a hard real-time system since output results must be produced in response to input conditions

within a limited time.

5.1.1 DEFINITION :

As per NEMA Standards a programmable controller is defined as a “DIGITALLY

OPERATING ELECTRONIC APPARATUS” which uses a Programmable memory

for the storage of instructions for specific functions such as logic sequencing, timing,

counting, and arithmetic control through digital or analog input/output modules, various types

of machines or processes. A digital computer which is used to performed the function of a

programmable controller is considered to be within this scope. Excluded are drum and similar

mechanical type sequencing controller.

Fig 5.1 PLC S7 300

5.2 BUILDING BLOCK OF PLC :

Fig 5.2 Building block of PLC

5.3 CONSTITUENTS OF PLC :

The programmable controller has three main units.

PROCESSOR OR CENTRAL PROCESSING UNIT(CPU) AND

MEMORY: The processor reads input signals in response to them it generates

output commands by interpreting the instructions from the program which is stored in

the memory.

INPUT/OUTPUT RACK OR INTERFACE:

This is the interface between the application devices and the processor. The I/O rack

receives information signals from the input devices and transmits action signals to the

controlled devices.

PROGRAMMABLE PANEL OR PROGRAMMING,EDITING AND

MONITORING DEVICE:

Individual instructions which form the programmable controller program are entered

into the memory through the keyboard or program panel. These instructions are shown in the

program panel display in the from of individual ladder diagram type rungs. The program

panel provides a reading of the programmable controller program for verification. It permits

changes (editing) of existing programs and also aids in machines or process start –ups and in

trouble shooting.

5.4 PLC SCAN :

A PLC program is generally executed repeatedly as long as the controlled system is running

referred to as a scan. A PLC scan starts with the CPU reading the status of inputs. The status

of physical input points is copied to an area of memory accessible to the processor,

sometimes called the "I/O Image Table". The program is then run from its first instruction

rung down to the last rung. It takes some time for the processor of the PLC to evaluate all the

rungs and update the I/O image table with the status of outputs. As PLCs became more

advanced, methods were developed to change the sequence of ladder execution, and

subroutines were implemented.

5.5 HOW IT DIFFER FROM THE COMPUTERS ?

The memory unit of the processor sequentially scans input (sensors, limit switches, push

buttons, photo cells) in cyclical fashion to determine which output (contacts, motors, starters,

solenoids, pilot lamps, converters etc.) it should be turned ON or OFF. The programmable

controller processes instructions in a fixed cycle. The instructions can be skipped or not

performed, but they are all at least examined on every scan. Computers, on the other hand

operate on an interrupt system where by changing events can alter the order in which the

instructions are performed. This speeds response time in relation to programmable controllers

but acts complexity to programming.

The second difference between computers and programmable controllers is in the manner by

which the controller is programmed. Ladder diagram the same used program electro-

mechanical relays, is also used in programmable controller. Control engineers working with

relays are familiar with relay ladder diagram logic and this makes the programmable

controller a shop tool and not a data process system.

The other distinguishing character of programmable controllers are their rugged construction,

equipment is designed to withstand jarring and freezing and elevated temperature, highly

humidity, corrosive atmosphere and electrical interference. While all PC’s are computers, by

definition, not all computers are PC’s. the difference is in environmental considerations,

programming methods and maintenance.

5.6 BASIC REQUIREMENTS :

In order to create a PLC program, the following items are needed :

PLC

Programming Device

Programming Software

Connector Cable

5.6.1 Programming Device :

The program is created in a programming device and then transferred to PLC. The program

for the S7 can be created using dedicated Siemens SIMANTIC S7 programming device, such

as a PG 720,A personal computer, with STEP 7 micro/lite installed, can be used as a

programming device with the S7.

Fig 5.6 Firmware

5.6.2 Programming Software:

A software program is required in order to tell the PLC what instructions it must follow. A

software package of one PLC , or one family of PLC’s ,such as the S7 family,would not be

useful on other PLC’s. A software based PLC requires a computer with an interface card, but

allows the PLC to be connected to sensors and other PLCs across a network.

5.6.3 Connector Cables :

A special cable is needed when a personal computer is used as a programming device. Two

versions of this cable are available. One is RS-585/PPI Multi –Master Cable ,and other is

USB/PPI Multi –Master Cable.

5.7 PROGRAMMING A PLC :

5.7.1 Ladder Logic :

Ladder logic is the main programming method used for PLCs. It is one programming

language used with PLC’s .Ladder logic uses components that resembles elements used in a

line diagram format to describe hard-wired control. The left of vertical line of a ladder logic

diagram represents the power or energized conductor. The output element represents the

neutral or return path of the circuit. Ladder logic diagrams are read from left to right ,top to

bottom. As mentioned before, ladder logic has been developed to mimic relay logic. The

decision to use the relay logic diagrams was a strategic one. By selecting ladder logic as the

main programming method, the amount of retraining needed for engineers and tradespeople

was greatly reduced.

5.7.2 Statement List :

A statement list provides another view of a set of instructions. The operation, what is to be

done, is shown on left. The operand ,the item to be operated by the operation ,is shown on the

right. A comparison between the statement list shown below, and the ladder logic shown on

the similar structure is terminated.

5.8 PROGRAM STRUCTURE : The programs of the PLC can either be linear or structured.

5.8.1 LINEAR PROGRAMMING : Programming individual operations in one section (block) is sufficient for handling simple

automation jobs. This is organization block1 (OB1). The PLC scans this block cyclically (i.e.,

after it scans last statements it goes back to the first statement and begins scanning again.

5.8.2 STRUCTURED PROGRAMMING : To solve complex tasks, it is advisable to divide a program into individual, self-contained

program parts (blocks).

The procedure has the following advantages:-

Simple and clear programming even for large program

Easy alteration

Simple program test

Simple startup

Subroutine techniques (block call from different locations)

Lower scan time extensions through STATUS PLC function

5.9 STEP 7 PROGRAMMING : STEP 7-Micro/Lite is the program software used with the S7 PLC to create the PLC

operating program. Step 7 consists of a number of instructions that must be arranged in a

logical order to obtain the desired PLC operation. These instructions are divided into 3

groups : Standard instructions, Special instructions, High –speed instructions.

The STEP 7 programming language has the following 5 block types:-

Organization blocks(OBs)

Organization blocks manage the control program

Program blocks (PBs)

Program blocks arrange the control program according to functional or technical aspects.

Sequence blocks (SBs)

Sequence blocks are special blocks that program sequence controls. They are handled like

program blocks.

Function blocks (FBs)

Function blocks are special blocks for programming frequently recurring or especially

complex program parts (e.g., reporting and arithmetic functions). The parameters can be

assigned. They have an extended set of operation (e.g., Jump operation within a block)

Data blocks (DBs)

Data blocks store data needed to process a control program. Actual values, limiting values

and texts are examples of data.

Blocks can be nested upto 16 levels in this particular controller.

5.10 ADVANTAGES :

Cost effective for controlling complex systems.

Flexible and can be reapplied to control other systems quickly and easily.

Computational abilities allow more sophisticated control.

Trouble shooting aids make programming easier and reduce downtime.

Reliable components make these likely to operate for years before failure.

Ease of programming using ladder circuits.

Ability to withstand rugged and adverse conditions of the factory floor.

They can withstand vibrations ,transients, noises etc.

They can withstand temperatures ranging from 0 to 50 degree centigrade.

5.11 APPLICATIONS :

Factory Automation

Machine Control

Instrumentation

Process Control

Data Acquisition and control

Manufacturing systems like CNC.

PROJECT

AUTOMATIC FEEDING, MEASURING

TEMPERATURE AND EJECTING OF COMPONENTS

USING PLC

AIM :- Automatic feeding, measuring temperature and ejecting of components using PLC.

EQUIPMENTS REQUIRED :-

1. Double Acting Cylinder

2. Directional Control Valves

3. Compressor

4. Tubes,banana cables

5. PLC

6. Sensors

Optical Sensors

Capacitive Sensors

7. Relays

8.PC.

INTRODUCTION :-

The project is to feed a component , measure temperature and eject the component

automatically. Automation used in this process for measuring temperature. Therefore in many

industries where temperature measuring of components is required , automation is used.

STEP IN THE PROCESS :-

1. The component is placed.

2. The feeder will measure temperature of the component.

3. The ejecting cylinder will eject the component.

4. The ejecting cylinder deactivates (come back).

5. Then the temperature measuring cylinder deactivates.

PROCEDURE :-

In this process we take 3 double acting cylinders (named A,B,C ) control valves and

connecting tubes as many as required.

Consider Cylinder A as Feeding Cylinder

Cylinder B as Temperature measuring Cylinder

Cylinder C as Ejecting cylinder

Here the forward stroke of the cylinder A is called as A+ and the backward stroke of

the cylinder is called A-. In this similar way B+,B- and C+,C-.

Here two optical sensors are used namely Optical sensor 1(S1) and Optical sensor 2(S2).

At first the components whose temperature has be measured has to be fed , this done by

forward stroke of the cylinder(A+) then after feeding the component the cylinder A has to

undergo the backward stroke(A-),then cylinder B has to undergo the forward stroke (B+) to

measure the temperature of the component and after the operation it performs the backward

stroke(B-). After B-, the cylinder C has to undergo forward stroke(C+) to eject the

component and the backward stroke (C-). i.e, A+A-B+B -C+C-.

All the actions are performed by connecting the components.

RESULTS AND CONCLUSIONS :-

The system has worked successfully by PLC. A minute change in the program causes the

total system to work differently.

Adding PLC to the electro pneumatic systems gives more flexible automation of

the system. Because the sequence of the operations by using PLC’s is very easy i.e. to change

the program, whereas it is much more difficult in pure pneumatic and electro pneumatic as

for every different sequence we need to rewire the connections.

Biblography & Reference

1.citdindia.org

2. google.com

3. wikipedia.com

4. vigorplc.com

5. hydraulicspneumatics.com

6. numatics.com

7. rotork.com