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709743 EN
MPS•
PA
Solutions
2 © Festo Didactic GmbH & Co. KG • MPS®
PA
The Festo Didactic Learning System has been developed and produced solely for
vocational and further training purposes in the field of process automation. The
company undertaking the training and / or the instructors is / are to ensure that
trainees observe the safety precautions specified in this workbook.
Festo Didactic herewith excludes any liability for damage or injury caused to
trainees, the training company and / or any third party, which may occur if the
system is in use for purposes other than purely for training; unless the said damage
/ injury has been caused by Festo Didactic deliberately or through gross negligence.
Order No.: Status: Authors: Editorial team: Graphics:
709743 12/2006 J. Helmich, ADIRO H. Kaufmann M. Linn V. Xhemajli, C. Green, T. Schwab, ADIRO
© Festo Didactic GmbH & Co. KG, 73770 Denkendorf, Germany, 2007 Internet: www.festo-didactic.com e-mail: did@de.festo.com
The copying, distribution and utilisation of this document as well as the communication of its contents to others without express authorisation is prohibited. Offenders will be held liable for the payment of damages. All rights reserved, in particular the right to carry out patent, utility model or ornamental design registration.
Parts of this documentation may be copied solely for training purposes by the authorised user.
Intended use
© Festo Didactic GmbH & Co. KG • MPS®
PA 3
Solutions – Filtration station
Solution 1.1: Analysis and appraisal of the system
Solution 1.1.1: Designation of the process components ______________________ 5
Solution 1.1.2: Completing the P&I diagram ________________________________ 7
Solution 1.1.3: Completing the pneumatic circuit diagram ____________________ 9
Solution 1.1.4: Determining the technical data of a system___________________ 11
Solution 1.1.5: Drawing up the allocation list ______________________________ 13
Solution 1.2: Measurement and control
Solution 1.2.1: Characteristics of the proportional pressure regulator/filter system16
Solution 1.2.2: Logic operation _________________________________________ 19
Solution 1.2.3: Operating range and operating point of a controlled system _____ 26
Solution 1.2.4: Identifying a controlled system_____________________________ 28
Solution 1.2.5: Ramped pressure stages__________________________________ 30
Solution 1.3: Closed-loop control
Solution 1.3.1: Two-position controller __________________________________ 32
Solution 1.3.2: Closed-loop control using continuous-action controllers (P, I, PI) _ 34
Solution 1.3.3: Controller setting according to Ziegler-Nichols ________________ 39
Solutions – Mixing station
Solution 2.1: Analysis and appraisal of the system
Solution 2.1.1: Designation of process components ________________________ 43
Solution 2.1.2: Completing the P&I diagram ______________________________ 45
Solution 2.1.3: Completing the pneumatic circuit diagram ___________________ 47
Solution 2.1.4: Determining the technical data of a system___________________ 49
Solution 2.1.5: Drawing up the allocation list ______________________________ 51
Solution 2.2: Measurement and control
Solution 2.2.1: Characteristics of the piping/pump system ___________________ 54
Solution 2.2.2: Logic operation _________________________________________ 61
Solution 2.2.3: Operating range and operating point of a controlled system_____ 69
Solution 2.2.4: Identifying a controlled system_____________________________ 71
Solution 2.2.5: Mixing according to quantity_______________________________ 73
Solution 2.3: Closed-loop control
Solution 2.3.1: Two-position controller ___________________________________ 76
Solution 2.3.2: Closed-loop control using continuous-action controllers (P, I, PI) _ 78
Solution 2.3.3: Manual setting of control parameters _______________________ 83
Contents
4 © Festo Didactic GmbH & Co. KG • MPS®
PA
Solutions – Reactor station
Solution 3.1: Analysis and appraisal of the system
Solution 3.1.1: Designation of process components ________________________ 85
Solution 3.1.2: Completing the P&I diagram _______________________________ 87
Solution 3.1.4: Determining the technical data of the system _________________ 89
Solution 3.1.5: Drawing up the allocation list ______________________________ 91
Solution 3.2: Measurement and control
Solution 3.2.1: Characteristics of the heating system medium ________________ 94
Solution 3.2.2: Logic operation ________________________________________ 100
Solution 3.2.3: Operating range and operating point of a controlled system ____ 106
Solution 3.2.4: Identifying a controlled system____________________________ 108
Solution 3.3: Closed-loop control
Solution 3.3.1: Two-position controller __________________________________ 110
Solution 3.3.2: Closed-loop control using continuous-action controllers (P, I, PI) 112
Solution 3.3.3: Tuning method according to the rate of rise _________________ 117
Solutions – Filling station
Solution 4.1: Analysis and appraisal of the system
Solution 4.1.1: Designation of process components _______________________ 121
Solution 4.1.2: Completing the P&I diagram ______________________________ 123
Solution 4.1.3: Completing the pneumatic circuit diagram __________________ 125
Solution 4.1.4: Determining the technical data of the system ________________ 127
Solution 4.1.5: Drawing up the allocation list _____________________________ 129
Solution 4.2: Measurement and control
Solution 4.2.1: Characteristics of the metering tank-pump system ____________ 132
Solution 4.2.2: Logic operation ________________________________________ 136
Solution 4.2.3: Operating range and operating point of a controlled system ____ 142
Solution 4.2.4: Identifying a controlled system____________________________ 143
Solution 4.2.5: Inlet and outlet behaviour of the metering tank ______________ 145
Solution 4.3: Closed-loop control
Solution 4.3.1: Two-position controller _________________________________ 151
Solution 4.3.2: Closed-loop control using continuous-action controllers (P, I, PI) 153
Solution 4.3.3: Optimisation method according to Chien-Hrones-Reswick (CHR)_ 158
Solutions MPS®
PA Filtration station
© Festo Didactic GmbH & Co. KG • MPS®
PA 5
Solution 1.1: Filtration station – system analysis and appraisal
Name: Date:
1.1.1 Designation of process components Sheet 1 of 2
3
1
2
4
Designation of process components
Solutions MPS®
PA Filtration station
6 © Festo Didactic GmbH & Co. KG • MPS®
PA
Solution1.1: Filtration station – system analysis and appraisal
Name: Date:
1.1.1 Designation of process components Sheet 2 of 2
No. Designation Meaning or function
1 1B1
Pressure sensor
2 F101
Filter
3 V102
Gate valve
4 V103
Butterfly valve
5 V106
3-way ball valve
In the electrical circuit diagram and P&I diagram of the filtration station you will find
two different designations for the gate valve.
– Explain the difference.
Comprehension questions
The designation V102 from the P&I diagram is a process designation. The process related functions in
an EMCS plan (Electronic Measuring Control System) are known as EMCS points. The measured
variable or another input variable, its processing, direction of action and positional data should be
based on this designation.
An EMCS point consists of a circle and is designated with a code letter ((A – Z) and a code number. The
code letters are entered in the upper section of the EMCS circle and the number in the lower section.
The sequence of code letters can be established from the table "EMSR code letters to DIN 19227".
The designation 1M4 from the electrical circuit diagram describes the electrical function.
All electrical equipment of an MPS®
PA station is labelled with equipment designations according to
the electrical circuit diagram. The designation of equipment in the electrical circuit diagrams is
effected according to the standard DIN/EN61346-2.
Designation
of process components
Solutions MPS®
PA Filtration station
© Festo Didactic GmbH & Co. KG • MPS®
PA 7
Solution 1.1: Filtration station – system analysis and appraisal
Name: Date:
1.1.2 Completing the P&I diagram Sheet 1 of 2
P&I diagram
Solutions MPS®
PA Filtration station
8 © Festo Didactic GmbH & Co. KG • MPS®
PA
Solution 1.1: Filtration station – system analysis and appraisal
Name: Date:
1.1.2 Completing the P&I diagram Sheet 2 of 2
Designation Meaning or function
F Filter
LS- Proximity sensor
LA+ Status, limit value alarm
P101 Digital pump
V Valve
– State the difference between the measuring point designations
LA+ and LS+.
Comprehension questions
The designations LA+ and LS+ differ with regard to the function within the station. Whereas both
sensors indicate the water level in the tank, LA+ signals an error message. (often in the form of
Emergency-Stop).
Functional description of
components
Solutions MPS®
PA Filtration station
© Festo Didactic GmbH & Co. KG • MPS®
PA 9
Solution 1.1: Filtration station – system analysis and appraisal
Name: Date:
1.1.3 Completing the pneumatic circuit diagram Sheet 1 of 2
Pneumatic circuit diagram
Solutions MPS®
PA Filtration station
10 © Festo Didactic GmbH & Co. KG • MPS®
PA
Solution 1.1: Filtration station – system analysis and appraisal
Name: Date:
1.1.3 Pneumatischen Schaltplan vervollständigen Sheet 2 of 2
Symbol Meaning or function
Flow control valve
5/2-way valve
Butterfly valve with pneumatic swivel actuator
– What is the meaning of the 5/2-way valve designation?
– What is the function of a flow control valve on a pneumatic cylinder?
Comprehension question
The 5/2-way valve has 5 ports and 2 switching positions. One port is intended for the supply of
compressed air. The remaining 4 ports are for the connection of the working and exhaust lines.
Depending on the design, the valve can be actuated either by means of applied pressure via pilot air
or electronically.
Exhaust air flow control valves are screwed into the exhaust ports 3 and 5 of control valves and enable
the regulation of cylinder piston speed by means of exhaust air restriction. The flow control screw
facilitates an adjustable restriction of exhaust air. The exhaust air is discharged via the integrated
silencer to reduce noise levels.
Functional description
of pneumatic components
Solutions MPS®
PA Filtration station
© Festo Didactic GmbH & Co. KG • MPS®
PA 11
Solution 1.1: Filtration station – system analysis and appraisal
Name: Date:
1.1.4 Determining the technical data of a system Sheet 1 of 2
Component Designation
in flow
diagram
Function Characteristics
Pump P201
Delivers a liquid
from a tank via the
piping system
Voltage [V] 24 V
Electrical power [W] 26 W
Max. throughput [l/min] 9
l/min
Proportional
pressure
regulator
Prop_V
Regulates pressure
proportional to a
preset setpoint
value.
Setpoint voltage [V] 0 - 10 V
Druckbereich [bar] 0.15 - 6 bar
3-way ball
valve V106
Changes the
direction of flow
within the station
Min. pneum. pressure [bar] 1 bar
Power consumption [W] 5.65 W
Pressure
sensor
1B1
Measures pressure
Pressure range [bar] 0 - 10 bar
Sensor signal [V] 0 - 10 V
Limit switch
top ( B101)
LS + 101
Status, upper limit
value
Filling amount up to contact [l] 6 l
Type (normally open/
normally closed) Norm. open
Limit switch
bottom
(B101)
LS- 102
Status, lower limit
value
Filling amount up to contact [l] 0 l
Type (normally open/
normally closed) Norm. open
Implementation
Technical data
Solutions MPS®
PA Filtration station
12 © Festo Didactic GmbH & Co. KG • MPS®
PA
Solution 1.1: Filtration station – System analysis and appraisal
Name: Date:
1.1.4 Determining the technical data of a system Sheet 2 of 2
– Describe the design and function of a proportional pressure regulator?
Comprehension questions
The proportional pressure regulator is used to control pressure proportional to a preset setpoint
value. Its main function is to be able to replace previously manually adjustable pressure regulators
with electrical, remotely adjustable regulators, for example in order for different machine parameters
to be automatically and instantly available. An integrated pressure sensor determines the pressure at
the working port and compares this value with the setpoint value. In the case of setpoint/actual
deviations, the regulating valve remains actuated until the output pressure has reached the setpoint
value.
Solutions MPS®
PA Filtration station
© Festo Didactic GmbH & Co. KG • MPS®
PA 13
Solution 1.1: Filtration station – system analysis and appraisal
Name: Date:
1.1.5 Drawing up the allocation list Sheet 1 of 3
Symbol EasyPort /
Simbox
address
PLC address Description Check
1B1 DI 0 I 0.0 Air jet pressure
1B2 DI 1 I 0.1 Tank B101 top
1B3 DI 2 I 0.2 Tank B101 bottom
1B4 DI 3 I 0.3 Tank B102 top
1B5 DI 4 I 0.4 Tank B102 unten
1B6/1B7 DI 5 I 0.5 Butterfly valve open and gate valve
down
1B8/1B9 DI 6 I 0.6 Butterfly valve open and gate valve
up
1PA_FREE DI 7 I 0.7 Receiver downstream station free
Symbol EasyPort /
Simubox
address
PLC address Description Check
1PV1 AI0 EW256 Actual value X (pressure)
Allocation list of
digital inputs
Allocation list of
analogue inputs
Solutions MPS®
PA Filtration station
14 © Festo Didactic GmbH & Co. KG • MPS®
PA
Solution 1.1: Filtration station – system analysis and appraisal
Name: Date:
1.1.5 Drawing up the allocation list Sheet 2 of 3
Symbol EasyPort /
Simubox
address
PLC address Description Check
1M1 DO 0 O 0.0 Air jet pressure
1M2 DO 1 O 0.1 Pump P101, waste water
1M3 DO 2 O 0.2 Pumpe P102, downstream station
1M4 DO 3 O 0.3 Gate valve
1M5 DO 4 O 0.4 Butterfly valve
1M6 DO 5 O 0.5 3-way ball valve
1M7 DO 6 O 0.6 Stirrer
1PA_BUSY DO 7 O 0.7 PA station busy
Symbol EasyPort /
Simubox
address
PLC address Description Check
1CO1 AO 0 AW256 Manipulated variable Y,
Proportional pressure regulator
Allocation list of
digital outputs
Allocation list of
analogue outputs
Solutions MPS®
PA Filtration station
© Festo Didactic GmbH & Co. KG • MPS®
PA 15
Solution 1.1: Filtration station – system analysis and appraisal
Name: Date:
1.1.5 Drawing up the allocation list Sheet 3 of 3
– Describe the behaviour of the analogue final control element (proportional
pressure regulator) if actuated via an analogue signal.
Comprehension questions
The bridge in the connection board must be converted to „analogue“ to enable analogue control of an
analogue final control element.
The analogue final control element responds as a function of the voltage applied. The valve is closed
in the unactuated state, i.e. if 0V voltage is applied. If an analogue signal is applied, the valve
response is proportional to the signal level. Pressure is thus infinitely adjustable as required.
Solutions MPS®
PA Filtration station
16 © Festo Didactic GmbH & Co. KG • MPS®
PA
Solution 1.2: Filtration station – measurement and control
Name: Date:
1.2.1 Characteristics of the proportional pressure regulator/filter system Sheet 1 of 3
The solution has been realised using digital/analogue EasyPort and FluidLab®
-PA.
Voltage at
prop_V in V 0,00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00
Signal
pressure
sensor in V
0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.00 3.00 3.00 3.00
Pressure
in bar. 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.00 3.00 3.00
3.00
Voltage at
prop_V in V 5.50 6.00 6.50 7.00 7.50 8.00 8.50 9.00 9.50 10.00
Signal
pressure
sensor in V
3.00 3.00 3.00 3.00 3.00 3.00 3.00 3.00 3.00 3.00
Pressure
in bar. 3.00 3.00 3.00 3.00 3.00 3.00 3.00 3.00 3.00
3.00
Control of proportional pressure regulator.
Note
Value table
Solutions MPS®
PA Filtration station
© Festo Didactic GmbH & Co. KG • MPS®
PA 17
Solution 1.2: Filtration station – measurement and control
Name: Date:
1.2.1 Characteristics of the proportional pressure regulator/filter system Sheet 2 of 3
The solution has been realised using digital/analogue EasyPort and FluidLab®
-PA.
Note
Characteristics of prop_V-
Filter system
Solutions MPS®
PA Filtration station
18 © Festo Didactic GmbH & Co. KG • MPS®
PA
Solution 1.2: Filtration station – measurement and control
Name: Date:
1.2.1 Characteristics of the proportional pressure regulator/filter system Sheet 3 of 3
The solution has been realised using digital/analogue EasyPort and FluidLab®
-PA.
No. Question Answer Comment
1 Form of characteristic curve Linear
A small hysteresis
exists. Operating
range only up to
3 bar.
2 Hysteresis is dependent on: The speed of the setpoint change Greater hysteresis
with higher speeds
Slow setpoint change
H = 0.1 3 Determine hysteresis:
Fast setpoint value change
H = 0.3
4
What setpoint value (V)
must be set if the filter is to
be flushed using the
pressure given opposite?
p = 0.5 bar = 0.5 Volt
p = 1.0 bar = 1.0.Volt
p = 1.5 bar = 1.5.Volt
– Explain the characteristic curve!
– State the reasons for the system response at low voltages!
Comprehension questions
At low voltages, the proportional pressure regulator is not within the preset operating range. The
linear range of the proportional pressure regulator begins as from 0.15 volts.
Note
Solutions MPS®
PA Filtration station
© Festo Didactic GmbH & Co. KG • MPS®
PA 19
Solution 1.2: Filtration station – measurement and control
Name: Date:
1.2.2 Logic operation Sheet 1 of 7
– Pushbutton S1, start of „stirring“ subprocess
– Pushbutton S2, start of „filtration“ subprocess
– Pushbutton S3, start of „flushing“ subprocess
The solution has been realised using digital/analogue EasyPort and FluidSIM®
Setting condition for stirrer R104
P&I
diagram
symbol
Electr.
circuit
diagram
symbol
Address Logic
operation
Comment
- S1 - & Pushbutton
LS- 102 1B3 DI 2 & Sensor
(lower filling level at Tank B101)
- 1B9 DI 6 & Sensor
(gate valve up)
Resetting condition for stirrer R104
P&I
diagram
symbol
Electr.
circuit
diagram
symbol
Address Logic
operation
Comment
- S2 - ≥1 Pushbutton
- S3 - ≥1 Pushbutton
LS- 102 1B3 DI 2 ≥1 Not sensor
(lower filling level at tank B101)
- 1B9 DI 6 ≥1 Not sensor
(gate valve up)
Solution
Note
Solutions MPS®
PA Filtration station
20 © Festo Didactic GmbH & Co. KG • MPS®
PA
Solution 1.2: Filtration station – measurement and control
Name: Date:
1.2.2 Logic operation Sheet 2 of 7
Setting condition for gate valve V102
P&I
diagram
symbol
Electr.
circuit
diagram
symbol
Address Logic
operation
Comment
- S2 - & Pushbutton
LS- 102 1B3 DI 2 & Sensor
(lower filling level at tank B101)
- 1B7 DI 5 & Not sensor
(butterfly valve open)
Resetting condition for gate valve V102
P&I
diagram
symbol
Electr.
circuit
diagram
symbol
Address Logic
operation
Comment
- S1 - ≥1 Pusbutton
- S3 - ≥1 Pusbutton
LS+ 101 1B2 DI 1 ≥1 Sensor
(upper filling level at tank B101)
LS+ 103 1B4 DI 3 ≥1 Sensor
(upper filling level at tank B102)
LS- 102 1B3 DI 2 ≥1 Not sensor
(lower filling level at tank B101)
Solutions MPS®
PA Filtration station
© Festo Didactic GmbH & Co. KG • MPS®
PA 21
Solution 1.2: Filtration station – measurement and control
Name: Date:
1.2.2 Logic operation Sheet 3 of 7
Setting condition for pump P102 - downstream station
P&I
diagram
symbol
Electr.
circuit
diagram
symbol
Address Logic
operation
Comment
- S3 - & Pushbutton
LS- 104 1B5 DI 4 & Sensor
(lower filling level at tank B102)
- 1B9 DI 6 & Sensor
(gate valve up)
Resetting condition for pump P102 – downstream station
P&I
diagram
symbol
Electr.
circuit
diagram
symbol
Address Logic
operation
Comment
- S1 - ≥1 Pushbutton
- S2 - ≥1 Pushbutton
LS+ 101 1B2 DI 1 ≥1 Sensor
(upper filling level at B101)
LS- 104 1B5 DI 4 ≥1 Not sensor
(lower filling level at tank B102)
Solutions MPS®
PA Filtration station
22 © Festo Didactic GmbH & Co. KG • MPS®
PA
Solution 1.2: Filtration station – measurement and control
Name: Date:
1.2.2 Logic operation Sheet 4 of 7
Setting condition for pump P101 – waste water pump
P&I
diagram
symbol
Electr.
circuit
diagram
symbol
Address Logic
operation
Comment
- S1 - ≥1 Pushbutton
- S2 - ≥1 Pushbutton
LS- 102 1B3 DI 2 & Sensor
(lower filling level at tank B101)
Resetting condition for pump 101 – waste water pump
P&I
diagram
symbol
Electr.
circuit
diagram
symbol
Address Logic
operation
Comment
- S3 - ≥1 Pushbutton
LS- 102 1B3 DI 2 ≥1 Not sensor
(lower filling level at tank B101)
LS+ 103 1B4 DI 3 & Sensor
(upper filling level at tank B102)
- 1B9 DI 6 & Not sensor
(gate valve up)
Solutions MPS®
PA Filtration station
© Festo Didactic GmbH & Co. KG • MPS®
PA 23
Solution 1.2: Filtration station – measurement and control
Name: Date:
1.2.2 Logic operation Sheet 5 of 7
– Stirrer R104 on
– Gate valve V102 up
Logic diagram
Network 1
Network 2
Solutions MPS®
PA Filtration station
24 © Festo Didactic GmbH & Co. KG • MPS®
PA
Solution 1.2: Filtration station – measurement and control
Name: Date:
1.2.2 Logic operation Sheet 6 of 7
– Pump P102 – downstream station on
– Pump P101 – waste water pump on
Network 3
Network 4
Solutions MPS®
PA Filtration station
© Festo Didactic GmbH & Co. KG • MPS®
PA 25
Solution 1.2: Filtration station – measurement and control
Name: Date:
1.2.2 Logic operation Sheet 7 of 7
– Why is air in the piping system to be avoided?
Comprehension questions
Air in the piping system prevents the correct operation of the system.
The pump must be prevented from running dry as this will cause damage to the pump.
Solutions MPS®
PA Filtration station
26 © Festo Didactic GmbH & Co. KG • MPS®
PA
Solution 1.2: Filtration station – measurement and control
Name: Date:
1.2.3 Determining the operating range and operating point of a controlled system Sheet 1 of 2
The solution has been realised using digital/analogue EasyPort and FluidLab®
-PA.
Determining the operating point of the controlled system
Pressure sensor Manipulated variable
prop_V [V] Pressure [bar] Output signal [V]
Minimum measured
value O.2 0.1 0.1
Operating point 3 1.25 1.25
Maximum measured
value 6.2 2.6 2.6
Note
Solutions MPS®
PA Filtration station
© Festo Didactic GmbH & Co. KG • MPS®
PA 27
Solution 1.2: Filtration station – measurement and control
Name: Date:
1.2.3 Determining the operating range and operating point of a controlled system Sheet 2 of 2
– Name the system conditions which could influence the operating range of the
proportional pressure regulator and effective range of the sensor.
Comprehension questions
A least 1 bar operating pressure must be available for the optimal operation of the proportional
pressure regulator.
The operating pressure has been reduced to 0 – 2.6 bar using a pressure limiter.
The sensor assembly position, as well as loss of air pressure, influence the measurement result of the
sensor.
Solutions MPS®
PA Filtration station
28 © Festo Didactic GmbH & Co. KG • MPS®
PA
Solution 1.2: Filtration station – measurement and control
Name: Date:
1.2.4 Identifying a controlled system Sheet 1 of 2
Example for the calculation of the time constant Ts
Solutions MPS®
PA Filtration station
© Festo Didactic GmbH & Co. KG • MPS®
PA 29
Solution 1.2: Filtration station – measurement and control
Name: Date:
1.2.4 Identifying a controlled system Sheet 2 of 2
– What is the value determined for the system gain Ks?
– What type of system, i.e. order of system are we dealing with?
– What is/are the time constant/s Ts obtained?
– Explain the system behaviour.
Comprehension questions
System gain Ks = 1
PT1, 1st order system
Ts = 32 ms
Self-regulating systems (PT1- controlled systems) are systems whose characteristic it is to „run on“.
The energy supplied then becomes = dissipated energy. The following applies in the case of a
pressure control system: The greater the applied pressure, the greater is the pressure level in the
filter. Consequently, the volumetric discharge from the filter increases with rising pressure. If the
output pressure is equal to the supply pressure, a final value (pressure compensation) exists,
whereby the pressure within the filter no longer changes.
Solutions MPS®
PA Filtration station
30 © Festo Didactic GmbH & Co. KG • MPS®
PA
Solution 1.2: Filtration station – measurement and control
Name: Date:
1.2.5 Pressure stages with ramp Sheet 1 of 2
The solution has been realised using digital/analogue EasyPort and FluidLab®
-PA.
Note
Solutions MPS®
PA Filtration station
© Festo Didactic GmbH & Co. KG • MPS®
PA 31
Solution 1.2: Filtration station – measurement and control
Name: Date:
1.2.5 Ramped pressure stages Sheet 2 of 2
– What is the difference between a proportional valve and a proportional pressure
regulator?
Comprehension questions
The proportional pressure regulator is used to control a pressure proportional to a preset setpoint
value. Its main function is to be able to replace previously manually adjustable pressure regulators
with electrical, remotely adjustable regulators, for example in order for different machine parameters
to be automatically and instantly available. An integrated pressure sensor determines the pressure at
the working port and compares this value with the setpoint value. In the case of setpoint/actual
deviations, the regulating valve remains actuated until the output pressure has reached the setpoint
value.
A proportional valve enables the flow control of neutral gases and liquids. It can be used as a remotely
adjustable final control element or in control loops. The proportional valve is a directly actuated
2/2-way valve. The valve piston is raised off its seat as a function of the solenoid coil current and
releases flow from port 1 to port 2. Without current, the valve is closed. The valve is spring returned.
An external standard signal is converted into a PWM signal whereby the valve opening is infinitely
adjustable. The frequency of the PWM signal can be adjusted to the valve used.
Evaluation
Solutions MPS®
PA Filtration station
32 © Festo Didactic GmbH & Co. KG • MPS®
PA
Solution 1.3: Filtration station – closed-loop control
Name: Date:
1.3.1 Two-position controller Sheet 1 of 2
The solution has been realised using digital/analogue EasyPort and FluidLab®
-PA.
Parameter Standardised
value
Physical value
Setpoint value (w) at
operating point
0.21 1.26
Upper switching limit - 0.5
Lower switching limit - 0.5
Note
Solutions MPS®
PA Filtration station
© Festo Didactic GmbH & Co. KG • MPS®
PA 33
Solution 1.3: Filtration station – closed-loop control
Name: Date:
1.3.1 Two-position controller Sheet 2 of 2
– How does the system respond?
– Describe the control behaviour.
– Name typical areas of application for two-position controllers.
Comprehension questions
The manipulated variable with this controller type can only assume two defined states. The controller
output in this case switches to and fro between these two states, depending on whether the upper or
lower threshold value has been exceeded. In our example, the manipulated variable jumps to its
maximum value at the moment of switch-on until the controlled variable reaches the upper threshold
value. The controller responds by decreasing the manipulated variable. The controlled variable
decreases until the lower setpoint value is reached and the reverse procedure begins.
Depending on requirement, the hysteresis can be increased or reduced, i.e. the switching interval is
reduced or prolonged.
The two-position controller is particularly suitable for the control of systems with large time constants;
in our example the control of pressure. Other areas of application are for example the control of a
compressor, the control of room temperature or humidity.
Evaluation
Solutions MPS®
PA Filtration station
34 © Festo Didactic GmbH & Co. KG • MPS®
PA
Solution 1.3: Filtration station – closed-loop control
Name: Date:
1.3.2 Closed-loop control using continuous-action controllers (P, I, PI) Sheet 1 of 5
Parameter Standardised
value
Physical
value [bar]
Setpoint value (w) at operating
point
0.21 1.3
Solutions MPS®
PA Filtration station
© Festo Didactic GmbH & Co. KG • MPS®
PA 35
Solution 1.3: Filtration station – closed-loop control
Name: Date:
1.3.2 Closed-loop control using continuous-action controllers (P, I, PI) Sheet 2 of 5
P controller
Example for Kp = 5
Implementation
Solutions MPS®
PA Filtration station
36 © Festo Didactic GmbH & Co. KG • MPS®
PA
Solution 1.3: Filtration station – closed-loop control
Name: Date:
1.3.2 Closed-loop control using continuous-action controllers (P, I, PI) Sheet 3 of 5
I controller
Example for Tn = 5
Implementation
Solutions MPS®
PA Filtration station
© Festo Didactic GmbH & Co. KG • MPS®
PA 37
Solution 1.3: Filtration station – closed-loop control
Name: Date:
1.3.2 Closed-loop control using continuous-action controllers (P, I, PI) Sheet 4 of 5
PI controller
Example for Kp = 2, Tn = 5
Implementation
Solutions MPS®
PA Filtration station
38 © Festo Didactic GmbH & Co. KG • MPS®
PA
Solution 1.3: Filtration station – closed-loop control
Name: Date:
1.3.2 Closed-loop control using continuous-action controllers (P, I, PI) Sheet 5 of 5
– How does the system respond with closed-loop control using a P controller?
– How does the system respond with closed-loop control using an I controller?
– How does the system respond with closed-loop control using a PI controller?
– Which PI parameter pair results in the smallest overshoot and/or smallest
adjustment time?
– Which controller is suitable for this controlled system if the system deviation is to
be corrected to zero?
Comprehension questions
P controller: The system responds relatively rapidly to the input step. The disadvantage is the
remaining system deviation. If the Kp selected is too large, the system starts to oscillate.
I controller: The system responds very slowly to a setpoint value change. The advantage is that the
system deviation is corrected to zero.
PI controller: The system responds relatively quickly to a setpoint value change. The system deviation
is completely is completely corrected. The PI controller combines the positive properties of a P and I
controller. The P component ensures a quick step response and the I controller ensures that system
deviations are corrected to the setpoint value.
Since the pressure control system is a P-controlled system, the I controller is ideally suited for closed-
loop control.
Solutions MPS®
PA Filtration station
© Festo Didactic GmbH & Co. KG • MPS®
PA 39
Solution 1.3: Filtration station – closed-loop control
Name: Date:
1.3.3 Optimisation method to Ziegler-Nichols Sheet 1 of 4
The solution has been realised using digital/analogue EasyPort and FluidLab®
-PA.
Note
Solutions MPS®
PA Filtration station
40 © Festo Didactic GmbH & Co. KG • MPS®
PA
Solution 1.3: Filtration station – closed-loop control
Name: Date:
1.3.3 Optimisation method to Ziegler-Nichols Sheet 2 of 4
– Which value have you selected and why?
– What is the value determined for Kp, Tn, Tv?
– What criteria are you using to evaluate your result?
Comprehension questions
Kp: P controller: 2.2
PI controller: 1.98
PID controller: 2.64
Tn: PI controller: 0.298
PID controller: 0.175
Tv: PID controller: 0.042
On the basis of the preset parameters, different response patterns can be read at the step response.
In the case of closed-loop control using a P controller, the output signal is relatively quick in the
steady state, although the system deviation cannot be corrected. If the experiment is conducted using
a PI controller, a slight overshoot of the output variable can be observed. The setpoint value is
reached quickly without remaining system deviation. The PID controller effects the fastest correction
of the system deviation. The steady state is reached after a few overshoots.
Evaluation
Solutions MPS®
PA Filtration station
© Festo Didactic GmbH & Co. KG • MPS®
PA 41
Solution 1.3: Filtration station – closed-loop control
Name: Date:
1.3.3 Optimisation method to Ziegler-Nichols Sheet 3 of 4
Example for Kpr = 2.2.
Example for Kpr = 1.98, Tn = 0.298.
Solutions MPS®
PA Filtration station
42 © Festo Didactic GmbH & Co. KG • MPS®
PA
Solution 1.3: Filtration station – closed-loop control
Name: Date:
1.3.3 Optimisation method to Ziegler-Nichols Sheet 4 of 4
Example for Kpr = 2.64, Tn = 0.175, Tv = 0.042.
Solutions MPS®
PA Mixing station
© Festo Didactic GmbH & Co. KG • MPS®
PA 43
Solution 2.1: Mixing station – system analysis and appraisal
Name: Date:
2.1.1 Designation of process components Sheet 1 of 2
3
4
2
1
5
No. Designation Meaning or function
1 V201
2/2-way ball valve
2 B201
Holding tank
3 2B2
Proximity sensor „tank B201 top“
4 2B1
Flow sensor
5 P201
Mixing pump
Designation of
process components
Solutions MPS®
PA Mixing station
44 © Festo Didactic GmbH & Co. KG • MPS®
PA
Solution 2.1: Mixing station – system analysis and appraisal
Name: Date:
2.1.1 Designation of process components Sheet 2 of 2
You will find two different designations for the proximity sensor „tank B201 top“ in
the electrical circuit diagram and P&I diagram for the mixing station.
– Explain the difference.
Comprehension questions
The designation from the P&I diagram is a process designation. The process related functions in an
EMCS plan (EMCS = Electronic Measuring Control System) are known as EMCS points. The measured
variables or other input variables, their processing, direction of action and positional data should
follow from this designation.
An EMCS point consists of an EMCS circle and is designated with a code letter (A-Z) and a code
number. The code letters are entered in the upper section of the EMCS circle and the numbering in the
lower section. The sequence of code letters can be established on the basis of the table "EMSR code
letters to DIN 19227".
The designation from the electrical circuit diagram describes an electrical function.
All electrical equipment of an MPS®
PA station is identified by means of equipment designations
according to the electrical circuit diagram. The designation of equipment in the electrical circuit
diagrams is effected according to the standard DIN/EN61346-2.
Solutions MPS®
PA Mixing station
© Festo Didactic GmbH & Co. KG • MPS®
PA 45
Solution 2.1: Mixing station – system analysis and appraisal
Name: Date:
2.1.2 Completing the P&I diagram Sheet 1 of 2
Designation Meaning or function
FI Flow sensor
FIC Flow sensor
LS- Proximity sensor
LA+ Status, limit value alarm
P201 Analogue pump
V Valve
Solutions
P&I diagram
Functional description of
components
Solutions MPS®
PA Mixing station
46 © Festo Didactic GmbH & Co. KG • MPS®
PA
Solution 2.1: Mixing station – system analysis and appraisal
Name: Date:
2.1.2 Completing the P&I diagram Sheet 2 of 2
– What is the difference between the designations of the measuring points FI and
FIC?
– What is the difference between the designations of the measuring points LA+ and
LS+?
Comprehension questions
The designations FI and FIC are process designations. An EMCS point consists of an EMCS circle and is
designated by a code letter (A-Z) and a code number. The code letters are entered in the upper section
of the EMCS circle and the numbering in the lower section. The sequence of the code letters is
established on the basis of the table "EMSR code letters to DIN 19227".
Example: F stands for flow; I stands for display (indicator); C corresponds to closed-loop control, i.e.
the sensor supplies an analogue signal in the form of an actual value of the control loop.
The designations LA+ and LS+ differ with regard to their function within the station. Whilst both
sensors indicate the water level within the tank, LA+ signals an error (alarm) message (often used as
Emergency-Stop.
Evaluation
Solutions MPS®
PA Mixing station
© Festo Didactic GmbH & Co. KG • MPS®
PA 47
Solution2.1: Mixing station – system analysis and appraisal
Name: Date:
2.1.3 Completing the pneumatic circuit diagram Sheet 1 of 2
Pneumatic circuit diagram
Solutions MPS®
PA Mixing station
48 © Festo Didactic GmbH & Co. KG • MPS®
PA
Solution2.1: Mixing station – system analysis and appraisal
Name: Date:
2.1.3 Completing the pneumatic circuit diagram Sheet 2 of 2
Symbol Meaning or function
Flow control valve
5/2-way valve
Butterfly valve with pneumatic swivel actuator
– What is the meaning of the 5/2-way valve designation?
– What is the function of an exhaust air flow control?
Comprehension questions
The 5/2-way valve has 5 ports and 2 switching positions. One port is intended for the supply of
compressed air. The remaining 4 ports are for the connection of the working and exhaust lines.
Depending on the design, the valve can be actuated either by means of applied pressure via pilot air
or electronically.
Exhaust air flow control valves are screwed into the exhaust ports 3 and 5 of control valves and enable
the regulation of cylinder speed by means of exhaust air restriction. The flow control screw facilitates
an adjustable restriction of exhaust air. The exhaust air is discharged via an integrated silencer to
reduce noise levels.
Functional description of
pneumatic components
Solutions MPS®
PA Mixing station
© Festo Didactic GmbH & Co. KG • MPS®
PA 49
Solution 2.1: Mixing station – system analysis and appraisal
Name: Date:
2.1.4 Determining the technical data of the system Sheet 1 of 2
Component Designation
in flow
diagram
Function Characteristics
Pump P201 Pumps water into
the mixing tank
Voltage [V] 24 V
Electrical power [W] 26 W
Max. throughput [l/min] 9 l/min
Flow sensor 2B1
Measures
throughput of
liquid
Measuring principle:
The rotor generates pulses which are
converted into a voltage signal t
Measuring range [l/min] 0.3-9 l/min
Sensor signal [Hz] 40-1200 Hz
Measuring
transducer
F/U
2A1 Adapts the sensor
signal
Input:
Square-wave frequency generator 0-1 kHz
Limit switch
top
2B6
Status, upper limit
value
in tank B204
Filling quantity up to contact [l] 6 l
Type (normally open/
normally closed) Norm. open
Limit switch
bottom
2B7
Status, lower limit
value
in tank B204
Filling quantity up to contact [l] o.5 l
Type (normally open/
normally closed) Norm. open
Technical data
Solutions MPS®
PA Mixing station
50 © Festo Didactic GmbH & Co. KG • MPS®
PA
Solution 2.1: Mixing station – system analysis and appraisal
Name: Date:
2.1.4 Determining the technical data of the system Sheet 2 of 2
– What is the frequency delivered by the flow sensor for a flow rate of 2l/min?
Solution by calculation is required!
Comprehension questions
s
pulseIm67,266
s60
pulseIm80002
s
dm
pulseIm8000
min
l2
f
s
pulseIm40
s60
pulseIm80003.0
s
dm
pulseIm8000
min
l3.0
f
s
1f
dm
Impulse8000FactorK
3
min/l2
3
min
3
=
⋅
=
⋅
=
=
⋅
=
⋅
=
=
=−
Solutions MPS®
PA Mixing station
© Festo Didactic GmbH & Co. KG • MPS®
PA 51
Solution 2.1: Mixing station – system analysis and appraisal
Name: Date:
2.1.5 Drawing up the allocation list Sheet 1 of 3
Symbol EasyPort /
Simbox
address
PLC address Description Check
2B1 DI 0 I 0.0 Flow sensor
2B2 DI 1 I 0.1 Holding tank B201 top
2B3 DI 2 I 0.2 Holding tank B201 bottom
2B4 DI 3 I 0.3 Holding tank B202 bottom
2B5 DI 4 I 0.4 Holding tank B203 bottom
2B6 DI 5 I 0.5 Mixing tank B204 top
2B7 DI 6 I 0.6 Mixing tank B204 bottom
2PA_Free DI 7 I 0.7 Receiver PA downstream station
free
Symbol EasyPort /
Simubox
address
PLC address Description Check
2PV1 AI0 IW256 Actual value X (flow) √
Allocaion list of
digital inputs
Allocation list of
analogue inputs
Solutions MPS®
PA Mixing station
52 © Festo Didactic GmbH & Co. KG • MPS®
PA
Solution 2.1: Mixing station – system analysis and appraisal
Name: Date:
2.1.5 Erstellen der Zuordnungsliste Sheet 2 of 3
Symbol EasyPort /
Simubox
address
PLC address Description Check
2M1 DO 0 O 0.0 Mixing pump P201 on √
2M2 DO 1 O 0.1 Pump P202, downstream station, on √
2M3 DO 2 O 0.2 Mixing valve V201 on √
2M4 DO 3 O 0.3 Mixing valve V202 on √
2M5 DO 4 O 0.4 Mixing valve V203 on √
Not busy DO 5 Not busy Not busy √
Not busy DO 6 Not busy Not busy √
2PA_Busy DO 7 O 0.7 Sender PA station busy √
Symbol EasyPort /
Simubox
address
PLC address Description Check
2CO1 AO 0 AW256 Manipulated variable Y, (pump
P201) √
Allocation list of
digital outputs
Allocation list of
analogue outputs
Solutions MPS®
PA Mixing station
© Festo Didactic GmbH & Co. KG • MPS®
PA 53
Solution 2.1: Mixing station – system analysis and appraisal
Name: Date:
2.1.5 Drawing up the allocation list Sheet 3 of 3
– What particular situation should be considered if the analogue final control
element (pump) is to be digitally controlled?
Comprehension questions
The bridge in the connection board must be converted to „digital“ to enable digital control of the
analogue final control element.
Solutions MPS®
PA Mixing station
54 © Festo Didactic GmbH & Co. KG • MPS®
PA
Solution 2.2: Mixing station – measurement and control
Name: Date:
2.2.1 Characteristics of the piping/pump system Sheet 1 of 7
The solution has been realised using digital/analogue EasyPort, and FluidLab®
-PA.
Voltage at
pump
control in V
0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00
Flow sensor
signal in V 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.2 0.7
Flow rate
in l/min. 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.12 0.44
Voltage at
pump
control in V
5.50 6.00 6.50 7.00 7.50 8.00 8.50 9.00 9.50 10.00
Flow sensor
signal in V 1.5 1.7 1.9 2.6 3.0 3.5 3.8 4.1 4.4 4.8
Flow rate
in l/min. 1.1 1.25 1.45 1.9 2.4 2.6 2.9 3.05 3.3 3.6
Water is pumped only from holding tank 1.
Note
Value table
holding tank 1
Solutions MPS®
PA Mixing station
© Festo Didactic GmbH & Co. KG • MPS®
PA 55
Solution 2.2: Mixing station – measurement and control
Name: Date:
2.2.1 Characteristics of the piping/pump system Sheet 2 of 7
Voltage at
pump
control in V
0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5,00
Flow sensor
signal in V 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.2 0.3 0.8 1,7
Flow rate
in l/min. 0.0 0.0 0.0 0.0 0.0 0.0 0.06 0.18 0.27 0.6 1,2
Voltage at
pump
control in V
5.50 6.00 6.50 7.00 7.50 8.00 8.50 9.00 9.50 10.00
Flow sensor
signal in V 1.9 2.2 2.5 2.8 3.0 3.2 3.6 3.9 4.4 4.8
Flow rate
in l/min. 1.4 1.6 1.8 2.1 2.3 2.4 2.7 2.95 3.3 3.6
Water is pumped only from holding tank 2.
Value table
Holding tank 2
Solutions MPS®
PA Mixing station
56 © Festo Didactic GmbH & Co. KG • MPS®
PA
Solution 2.2: Mixing station – measurement and control
Name: Date:
2.2.1 Characteristics of the piping/pump system Sheet 3 of 7
Voltage at
pump
control in V
0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00
Flow sensor
signal in V 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.2 0.5 1.1 1.5
Flow rate in
l/min. 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.13 0.4 0.8 1.1
Voltage at
pump
control in V
5.50 6.00 6.50 7.00 7.50 8.00 8.50 9.00 9.50 10.00
Flow sensor
signal in V 1.8 2.2 2.7 2.9 3.1 3.5 3.8 4.2 4.4 4.7
Flow rate in
l/min. 1.3 1.65 2.0 2.2 2.4 2.6 2.8 3.1 3 3.5
Water is pumped only from holding tank 3.
Value table
holding tank 3
Solutions MPS®
PA Mixing station
© Festo Didactic GmbH & Co. KG • MPS®
PA 57
Solution 2.2: Mixing station – measurement and control
Name: Date:
2.2.1 Characteristics of the piping/pump system Sheet 4 of 7
Voltage at
pump
control in V
0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.0
Flow sensor
signal in V 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.2 0.8 1. 1.
Flow rate
in l/min. 0.0 0.0 0.0 0.0 0.0 0.0 0.04 1.18 0.6 1.0 1.3
Voltage at
pump
control in V
5.50 6.00 6.50 7.00 7.50 8.0 8.50 9.00 9.50 10.00
Flow sensor
signal in V 2.1 2.4 2.7 3.0 3.6 3.9 4.1 4.3 4.7 4.9
Flow rate in
l/min. 1.55 1.8 2.0 2.3 2.7 2.9 3.1 3.3 3.5 3.7
Water is pumped simultaneously from all holding tanks.
All holding tanks are filled identically prior to starting.
Value table
holding tank 1 – 3
Solutions MPS®
PA Mixing station
58 © Festo Didactic GmbH & Co. KG • MPS®
PA
Solution 2.2: Mixing station – measurement and control
Name: Date:
2.2.1 Characteristics of the piping/pump system Sheet 5 of 7
Holding tank 1
Holding tank 2
Solutions MPS®
PA Mixing station
© Festo Didactic GmbH & Co. KG • MPS®
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Solution 2.2: Mixing station – measuring and control
Name: Date:
2.2.1 Characteristics of the piping/pump system Sheet 6 of 7
Holding tank 3
Holding tank 1 – 3
Solutions MPS®
PA Mixing station
60 © Festo Didactic GmbH & Co. KG • MPS®
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Solution 2.2: Mixing station – measurement and control
Name: Date:
2.2.1 Characteristics of the piping/pump system Sheet 7 of 7
– Compare the characteristic curves and discuss the possible causes which result
in their differences.
– State the reasons for the system response with a decreasing quantity of water in
the holding tank.
– State the reasons for the system behaviour at low voltages.
– What would be the effect on the characteristic curves of different quantities of
water in the holding tank?
Comprehension questions
The cause of the different characteristic curves is the different piping systems on the one part and the
different quantities of water in the holding tank on the other. Depending on the length of the
controlled system, the work to be carried out increases in order to pump the liquid into the mixing
tank. With a decreasing fill level in the holding tanks, the pressure of the water gauge drops to the
tank floor whereby the pressure in the piping system also decreases. This means that the decrease in
flow velocity is proportional to the reducing tank level.
At low voltages the pump does not operate within its operating range. The pump delivers its full
capacity only after a certain voltage is reached.
Different quantities of water result in different characteristic curves. The maximum flow rate of liquid
drops with a decrease in the level of water in the holding tanks. The characteristic curve exhibits a
flatter rise.
Solutions MPS®
PA Mixing station
© Festo Didactic GmbH & Co. KG • MPS®
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Solution 2.2: Mixing station – measurement and control
Name: Date:
2.2.2 Logic operation Sheet 1 of 8
– Pushbutton S1, to pump water from tank B201 into tank B204
– Pushbutton S2, to pump water from tank B202 into tank B204
– Pushbutton S3, to pump from tank B203 into tank B204
– Pushbutton S4, to pump water from tank B204 back into tank B201 or B202 or
B203.
The solution has been realised using digital/analogue EasyPort, and FluidSIM®
.
Setting condition for valve V201
P&I
diagram
symbol
Electr.
circuit
diagram
symbol
Address Logic
operation
Comment
- S1 - & Pushbutton
LS202 2B3 DI 2 & Sensor
(lower fill level at tank B201)
Resetting condition for valve V201
P&I
diagram
symbol
Electr.
circuit
diagram
symbol
Address Logic
operation
Comment
- S1 - ≥1 Not pushbutton
LS202 2B3 DI 2 ≥1 Not sensor
(lower fill level at tank B201)
Note
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PA Mixing station
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Solution 2.2: Mixing station – measurement and control
Name: Date:
2.2.2 Logic operation Sheet 2 of 8
Setting condition for valve V202
P&I
diagram
symbol
Electr.
circuit
diagram
symbol
Address Logic
operation
Comment
- S2 - & Pushbutton
LS203 2B4 DI 3 & Sensor
(lower fill level at tank B202)
Resetting condition for valve V202
P&I
diagram
symbol
Electr.
circuit
diagram
symbol
Address Logic
operation
Comment
- S2 - ≥1 Not pushbutton
LS203 2B4 DI 3 ≥1 Not sensor
(lower fill level at tank B202)
Solutions MPS®
PA Mixing station
© Festo Didactic GmbH & Co. KG • MPS®
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Solution 2.2: Mixing station – measurement and control
Name: Date:
2.2.2 Logic operation Sheet 3 of 8
Setting condition for valve V203
P&I diagram
symbol
Electr. circuit
diagram symbol
Address Logic
operation
Comment
- S3 - & Pushbutton
LS204 2B5 DI 4 & Sensor
(lower fill level at B203)
Resetting condition for valve V203
P&I diagram
symbol
Electr. circuit
diagram symbol
Address Logic
operation
Comment
- S3 - ≥1 Not pushbutton
LS204 2B5 DI 4 ≥1 Not sensor
(lower fill level at tank B203)
Setting condition for pump P201
P&I diagram
symbol
Electr. circuit
diagram
Address Logic
operation
Comment
- S1 - ≥1 Pushbutton
- S2 - ≥1 Pushbutton
- S3 - ≥1 Pushbutton
Resetting condition for pump P201
P&I diagram
symbol
Electr. circuit
diagram symbol
Address Logic
operation
Comment
- S1 - & Not pushbutton
- S2 - & Not pushbutton
- S3 - & Not pushbutton
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PA Mixing station
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Solution 2.2: Mixing station – measurement and control
Name: Date:
2.2.2 Logic operation Sheet 4 of 8
Setting condition for pump P202
P&I
diagram
symbol
Electr.
circuit
diagram
symbol
Address Logic
operation
Comment
- S4 - & Pushbutton
LS 206 2B7 DI 6 & Sensor
(lower fill level at tank B204)
Resetting condition for pump P202
P&I
diagram
symbol
Electr.
circuit
diagram
symbol
Address Logic
operation
Comment
- S4 - ≥1 Not pushbutton
LS 206 2B7 DI 6 ≥1 Not sensor
(lower fill level at tank B204)
Solutions MPS®
PA Mixing station
© Festo Didactic GmbH & Co. KG • MPS®
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Solution 2.2: Mixing station – measurement and control
Name: Date:
2.2.2 Logic operation Sheet 5 of 8
– Mixing valve V201 on
– Mixing valve V202 on
Logic diagram
Network 1
Network 2
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PA Mixing station
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Solution 2.2: Mixing station – measurement and control
Name: Date:
2.2.2 Logic operation Sheet 6 of 8
Mixing valve V203 on
– Pump P201 – mixing pump on
Network 3
Network 4
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PA Mixing station
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Solution 2.2: Mixing station – measurement and control
Name: Date:
2.2.2 Logic operation Sheet 7 of 8
– Pump P202 – mixing pump on
Network 5
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Solution 2.2: Mixing station – measurement and control
Name: Date:
2.2.2 Logic operation Sheet 8 of 8
– Why should air in the piping system be avoided?
Comprehension questions
Air in the piping system prevents the correct operation of a system.
Pumps must be prevented from running dry as this will cause damage to the pump.
Solutions MPS®
PA Mixing station
© Festo Didactic GmbH & Co. KG • MPS®
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Solution 2.2: Mixing station – measurement and control
Name: Date:
2.2.3 Determining the operating range and operating points of a controlled system Sheet 1 of 2
The solution has been realised using digital/analogue EasyPort and FluidLab®
-PA.
Determining the operating point of the flow rate control system
Flow sensor
operating range of pump Float flow meter
Manipulated
variable
pump P201
[V]
Flow rate
[l/min.]
Output signal
measuring
transducer [V]
Display value
[l/h]
Minimum measured
value 3.3 0.1 0.1 --
Operating point 6.6 2.6 2.6 125-
Maximum measured
value 10 4.9 4.9 240
Note
Solutions MPS®
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70 © Festo Didactic GmbH & Co. KG • MPS®
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Solution 2.2: Mixing station – measurement and control
Name: Date:
2.2.3 Determining the operating range and operating point of a controlled system Sheet 2 of 2
– State the system conditions which could influence the operating range of the
pump and the measuring range of the sensor.
Comprehension questions
Air in the piping system can influence the operating range of the pump. In addition the system is
dependent on the fill level of the holding tank. With a high fill level a high flow rate is reached, which
decreases with a drop in fill level. With a time variant measurement, the maximum flow rate therefore
decreases proportional to the current fill level.
If the pump is not operated within its operating range, e.g. if the selected pump voltage is too low, this
results in inaccurate measurement results. The operating range of the pump depends on the particular
piping system.
Evaluation
Solutions MPS®
PA Mixing station
© Festo Didactic GmbH & Co. KG • MPS®
PA 71
Solution 2.2: Mixing station – measurement and control
Name: Date:
2.2.4 Identifying a controlled system Sheet 1 of 2
The solution has been realised using digital/analogue EasyPort and FluidLab®
-PA.
T
Note
Solutions MPS®
PA Mixing station
72 © Festo Didactic GmbH & Co. KG • MPS®
PA
Solution 2.2: Mixing station – measurement and control
Name: Date:
2.2.4 Identifying a controlled system Sheet 2 of 2
– What is the value determined for the system gain Ks?
– What type of system, i.e. order of system, are we dealing with?
– What is/are the time constant(s) obtained?
– Explain the system behaviour?
Comprehension questions
Ks = 1
PT1, 1st order system.
Ts = 1.0s.
Self-regulating systems (PT1-controlled systems) are systems whose characteristics it is to „run on“ to
a final steady-state value after a certain time. The energy supplied then becomes dissipated energy.
The following applies in the case of a flow rate control system: Once the pump is switched on, the
pump blades within the pump start to draw in the liquid from the piping system and pump it to the
other side into the mixing tank. During this, the flow velocity increases rapidly. If the flow energy is
equal to the driving force of the pump blades, a steady state (equilibrium) exists whereby the flow
velocity no longer changes.
Solutions MPS®
PA Mixing station
© Festo Didactic GmbH & Co. KG • MPS®
PA 73
Solution 2.2: Mixing station – measurement and control
Name: Date:
2.2.5 Mixing according to quantity Sheet 1 of 3
The solution has been realised using digital/analogue EasyPort and FluidLab®
-PA.
Note
Solutions MPS®
PA Mixing station
74 © Festo Didactic GmbH & Co. KG • MPS®
PA
Solution 2.2: Mixing station – measurement and control
Name: Date:
2.2.5 Mixing according to quantity Sheet 2 of 3
Determining the operating point of the flow rate control system
Holding tank Mixing tank
No.
Desired
quantity
[ml]
Voltage at
pump [Volt] From tank No.
Water level
before Water level after Before After
1 1 2650 2470 1000 1200
2 2 2600 2410 1200 1400
3
500 4
3 2750 2650 1400 1490
4 1 2700 2500 1000 1250
5 2 2600 2400 1250 1450
6
500 6
3 2650 2550 1450 1550
7 1 2800 2600 1000 1250
8 2 2640 2420 1250 1400
9
500 7
3 2580 2460 1400 1500
10 1 2740 2520 1000 1250
11 2 2610 2400 1250 1450
12
500 9
3 2610 2500 1450 2600
Solutions MPS®
PA Mixing station
© Festo Didactic GmbH & Co. KG • MPS®
PA 75
Solution 2.2: Mixing station – measurement and control
Name: Date:
2.2.5 Mixing according to quantity Sheet 3 of 3
– Why can’t the transfer of a specific quantity be time-controlled?
– Why is the method of „mixing according to quantity“ better?
– Why is the quantity of water still not exact using this method?
– At what pump voltage do you get minimal measurement inaccuracies?
Comprehension questions
The flow rate during pumping is not constant which is why time-controlled measurement leads to
inaccurate results.
When „mixing according to quantity“ the actual flow rate is acquired and accumulated continuously
until the desired quantity of water is obtained. This method allows more accurate measurement..
Even so, the results do not meet expectation 100%. The reason lies within the system itself. The pump
and moving liquid are relatively inert. At the time it is switched off, the blades still continue to rotate
by a few rotations and so continues to transport a small quantity of liquid. Consequently, flow does
not stop immediately the pump is switched off but just a few split seconds later. The higher the flow
velocity, the more inaccurate is the measurement result. The same is the case with very low flow
velocities.
Minimal measurement inaccuracies are obtained using an applied pump voltage of 7 volts. The exact
quantity specified is pumped from the holding tanks into the mixing tank.
Solutions MPS®
PA Mixing station
76 © Festo Didactic GmbH & Co. KG • MPS®
PA
Solution 2.3: Mixing station – closed-loop control
Name: Date:
2.3.1 Two-position controller Sheet 1 of2
The solution has been realised using digital/analogue EasyPort and FluidLab®
-PA.
Parameter Standardised
value
Physical
Value
Setpoint value (w) at
operating point
O.35 2.63
Upper switching limit - 0.4
Lower switching limit - 0.4
Note
Solutions MPS®
PA Mixing station
© Festo Didactic GmbH & Co. KG • MPS®
PA 77
Solution 2.3: Mixing station – closed-loop control
Name: Date:
2.3.1 Two-position controller Sheet 2 of2
– How does the system respond?
– Describe the control behaviour.
– State some typical areas of application for two-position controllers.
Comprehension questions
The manipulated variable with this type of controller can only assume two defined states - in our
example 0 and Vmax, whereby the controller output switches to and fro between these two states,
depending on whether the upper or lower threshold value is exceeded. In our example, the
manipulated variable jumps to its maximum value the moment it is activated until the controlled
variable reaches the upper threshold value. The pump is switched off. The controlled variable now
decreases until the lower threshold value is reached and the reverse procedure begins.
The hysteresis can be increased or reduced according to requirement, i.e. the switching interval
reduced or extended.
The two-position controller is particularly suitable for the control of systems with large time constants;
in our example the regulation of a flow rate control system. Other areas of application are for example
the control of an air reservoir (compressor), the control of room temperature or humidity.
Solutions MPS®
PA Mixing station
78 © Festo Didactic GmbH & Co. KG • MPS®
PA
Solution 2.3: Mixing station – closed-loop control
Name: Date:
2.3.2 Closed-loop control using continuous-action controllers (P, I, PI) Sheet 1 of 5
The solution has been realised using digital/analogue EasyPort and FluidLab®
-PA.
Parameter Stadardised
value
Physical
value l/min
Setpoint value (w) at operating
point
0.3 2.6
Note
Solutions MPS®
PA Mixing station
© Festo Didactic GmbH & Co. KG • MPS®
PA 79
Solution 2.3: Mixing station – closed-loop control
Name: Date:
2.3.2 Closed-loop control using continuous-action controllers (P, I, PI) Sheet 2 of 5
P controller
Example for Kpr = 50
Solutions MPS®
PA Mixing station
80 © Festo Didactic GmbH & Co. KG • MPS®
PA
Solution 2.3: Mixing station – closed-loop control
Name: Date:
2.3.2 Closed-loop control using continuous-action controllers (P, I, PI) Sheet 3 of 5
I controller
Example for Tn = 2
Solutions MPS®
PA Mixing station
© Festo Didactic GmbH & Co. KG • MPS®
PA 81
Solution 2.3: Mixing station – closed-loop control
Name: Date:
2.3.2 Closed-loop control using continuous-action controllers (P, I, PI) Sheet 4 of 5
PI controller
Example for Kpr = 2, Tn = 2
Solutions MPS®
PA Mixing station
82 © Festo Didactic GmbH & Co. KG • MPS®
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Solution 2.3: Mixing station – closed-loop control
Name: Date:
2.3.2 Closed-loop control using continuous-action controllers (P, I, PI) Sheet 5 of 5
– How does the system respond with closed-loop control using a P controller?
– How does the system respond with closed-loop control using an I controller?
– How does the system respond with closed-loop control using a PI controller?
– Which PI parameter pair results in the smallest overshoot and/or shortest
settling time?
– Which controller is suitable for this controlled system, if the system deviation is
to be corrected to zero?
Comprehension questions
P controller: The system responds relatively rapidly to the input step. The disadvantage is the
remaining system deviation. If the Kp selected is too large, the system starts to oscillate.
I controller: The system reacts very slowly to a setpoint value change. The advantage is that the
system deviation is corrected to zero.
PI controller: The system reacts relatively fast to a setpoint value change. The system deviation is
completely corrected. The PI controller combines the positive characteristics of a P and I controller.
The P component ensures a fast step response, the I controller ensures that system deviations are
corrected to the setpoint value.
The smallest overshoot is obtained for Kpr=2 and Tn =2.
Since the flow rate control system is a P controlled system, the I controller is optimally suitable for
closed-loop control.
Solutions MPS®
PA Mixing station
© Festo Didactic GmbH & Co. KG • MPS®
PA 83
Solution 2.3: Mixing station – closed-loop control
Name: Date:
2.3.3 Manual tuning of controller parameters without knowledge of the system behaviour Sheet 1 of 2
The solution has been realised using digital/analogue EasyPort and FluidLab®
-PA.
Note
Solutions MPS®
PA Mixing station
84 © Festo Didactic GmbH & Co. KG • MPS®
PA
Solution 2.3: Mixing station – closed-loop control
Name: Date:
2.3.3 Manual tuning of controller parameters without knowledge of the system behaviour Sheet 2 of 2
– What is the value determined for Kp?
– What criteria are you using to evaluate your result?
Comprehension questions
The following values result for Kp and Tp for the setpoint value in the operating point:
Kp=2;
Tn=2;
Accuracy: The system deviation is completely corrected and maximum accuracy is therefore achieved.
This is due to the I component of the controller. Its function is to reach the exact setpoint value and
thus correct the system deviation between the input and output signal. The P component ensures a
fast system response.
Speed: A change in the parameters Kp and Tn influences the speed of the system. The greater the
reset time Tn, the greater is the rise time, whereby too small a selected Tn can result in overshoot. The
following applies for the proportional coefficient Kp: The larger the Kp, the smaller is the rise time. If
the Kp selected is too large, this results in overshoot of the characteristic curve and, in a worst case
scenario, in an oscillating system.
Solutions MPS®
PA Reactor station
© Festo Didactic GmbH & Co. KG • MPS®
PA 85
Solution 3.1: Reactor station – system analysis and appraisal
Name: Date:
3.1.1 Designation of process components Sheet 1 of 2
Designation of process components
Solutions MPS®
PA Reactor station
86 © Festo Didactic GmbH & Co. KG • MPS®
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Solution 3.1: Reactor station – system analysis and appraisal
Name: Date:
3.1.1 Designation of process components Sheet 2 of 2
No. Designation Meaning or function
1 TIC301
Temperature sensor
2 B301
Reactor tank
3 R304
Stirrer
4 W303
Heater
5 P301
Cooling pump
You will find two different designations for the heater in the electrical circuit diagram
and P&I diagram of the reactor station.
– Explain the difference.
Comprehension questions
The designation from the P&I diagram is a process designation. The process related functions in an
EMCS plan (EMCS = Electronic Measuring Control System) are known as EMCS points. The measured
variables or other input variables, their processing, direction of action and positional data should
follow from this designation.
An EMCS point consists of a circle and is designated with a code letter (A-Z) and a code number. The
code letters are entered in the upper section of the EMCS circle and the numbering in the lower
section. The sequence of code letters can be established on the basis of the table "EMCS code letters
to DIN 19227".
The designation in an electrical circuit diagram describes an electrical function.
All electrical equipment of an MPS® PA station is identified by means of equipment designations
according to the electrical circuit diagram. The designation of equipment in the electrical circuit
diagrams is effected according to the standard DIN/EN°61°346-2.
Designation of
process components
Solutions MPS®
PA Reactor station
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Solution 3.1: Reactor station – system analysis and appraisal
Name: Date:
3.1.2 Completing the P&I diagram Sheet 1 of 2
P&I diagram
Solutions MPS®
PA Reactor station
88 © Festo Didactic GmbH & Co. KG • MPS®
PA
Solution 3.1: Reactor station – system analysis and appraisal
Name: Date:
3.1.2 Completing the P&I diagram Sheet 2 of 2
Designation Meaning or function
W303 Heater
TIC Temperature sensor
LS+ Proximity sensor
LA+ Status, limit value alarm
TA+ Temperature sensor, alarm
V Valve
– What is the difference between the measuring point designations TIC and TA+?
– What is the difference between the measuring point designations LA+ and LS+?
Comprehension questions
The designations TA+ and TIC are process designations. An EMCS point consists of an EMCS circle and
is designated with a code letter (A-Z) and a code number. The code letters are entered in the upper
section of the EMCS circle and the numbering in the lower section. The sequence of code letters is
established on the basis of the table "EMCS code letters to DIN 19227".
Example: T stands for temperature; I stands for display; C corresponds to automatic control, i.e. the
sensor supplies an analogue signal in the form of an actual value of the control loop.
TA corresponds to a sensor with alarm
The designations LA+ and LS+ differ with regard to their function within the station. Whilst both
sensors indicate the level of water within the tank, LA+ signals an error message (often used as
Emergency-Stop.
Functional description
of components
Solutions MPS®
PA Reactor station
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Solution 3.1: Reactor station – system analysis and appraisal
Name: Date:
3.1.4 Determining the technical data of a system Sheet 1 of 2
Component Designation
in flow
diagram
Function Characteristics
Heater W303
Heats water in the
reactor tank
Heating capacity [W] 1000 W
Control voltage [V DC] 24 V
Temperature
sensor
TIC301
Measures water
temperature
Measuring principle:
The change in the electrical resistance of the
platinum wire is measured and converted
into a voltage
Measuring range [°C] -50 - 150°C
Sensor resistor PT100
Pump P301 Transfers water via
pump
Voltage [V] 24 V
Electric power [W] 26 W
Max. throughput [l/min] 9 l/min
Limit switch
top
LS+ 302
Status, upper limit
value
Filling quantity up to contact [l] 3 l
Type (n. open/n.closed n.open
contact
Limit switch
bottom
LS- 303
Status, lower limit
value
Filling quantity up to contact [l] 0 l
Type (n. open/n.closed) n.open
contact
Solutions MPS®
PA Reactor station
90 © Festo Didactic GmbH & Co. KG • MPS®
PA
Solution 3.1: Reactor station – system analysis and appraisal
Name: Date:
3.1.4 Determining the technical data of the system Sheet 2 of 2
– What is the resistance supplied by the temperature sensor for a temperature of
20 °C?
– What is the meaning of the term Pt100?
Comprehension questions
The sensor supplies a resistance of approx. 107.8 ohm for a temperature of 20°C.
The temperature sensor contains a platinum resistance thermometer with a positive temperature
coefficient. The sensor has a basic resistance value of 100 ohm at 0°C. (PT=Platinum).
Solutions MPS®
PA Reactor station
© Festo Didactic GmbH & Co. KG • MPS®
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Solution 3.1: Reactor station – system analysis and appraisal
Name: Date:
3.1.5 Drawing up the allocation list Sheet 1 of 3
For Simatic S7-300 CPU
Symbol EasyPort /
Simubox
address
PLC address Description Check
3B1 DI 0 I 0.0 Temperature sensor
3B2 DI 1 I 0.1 Holding tank B301 top
3B3 DI 2 I 0.2 Holding tank B301 bottom
Not busy DI 3 I 0.3 Not busy
Not busy DI 4 I 0.4 Not busy
Not busy DI 5 I 0.5 Not busy
Not busy DI 6 I 0.6 Not busy
3PA_Free DI 7 I 0.7 Receiver PA downstream station
free
Symbol EasyPort /
Simubox
address
PLC address Designation Check
3PV1 AI0 EW 256 Actual value X (temperature)
Note
Allocation list of
digital inputs
Allocation list of
analogue inputs
Solutions MPS®
PA Reactor station
92 © Festo Didactic GmbH & Co. KG • MPS®
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Solution 3.1: Reactor station – system analysis and appraisal
Name: Date:
3.1.5 Drawing up the allocation list Sheet 2 of 3
Symbol EasyPort /
Simubox
address
PLC address Designation Check
3M1 DO 0 O 0.0 Heater W303 on
3M2 DO 1 O 0.1 Pump P301
3M3 DO 2 O 0.2 Pump P302
3M4 DO 3 O 0.3 Stirrer R304
Not busy DO 4 O 0.4 Not busy
Not busy DO 5 O 0.5 Not busy
Not busy DO 6 O 0.6 Not busy
2PA_Busy DO 7 O 0.7 Sender PA Station busy
Symbol EasyPort /
Simubox
address
PLC address Designation Check
3CO1 AO 0 AW 256 Manipulated variable Y, (heater
W303)
Allocation list of
digital outputs
Allocation list of
analogue outputs
Solutions MPS®
PA Reactor station
© Festo Didactic GmbH & Co. KG • MPS®
PA 93
Solution 3.1: Reactor station – system analysis and appraisal
Name: Date:
3.1.5 Drawing up the allocation list Sheet 3 of 3
– What particular situation in the reactor station should be considered if the
analogue final control element (heater) is to be digitally controlled?
Comprehension questions
To enable digital control of the analogue final control element, the bridge in the connection board
must be converted to „digital“.
Solutions MPS®
PA Reactor station
94 © Festo Didactic GmbH & Co. KG • MPS®
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Solution 3.2: Reactor station – measurement and control
Name: Date:
3.2.1 Characteristics of the heating system medium Sheet 1 of 6
Symbol Designation Parameter Value
3M1 Heater Power P 522 W
3M1 Heater Voltage V 5.2 V DC
3M1 Heater Eficiency factor η 0.8 ( 80%)
H2O Water Specific heat capacity c 4182 J/(kg*K)
H2O Water Minimum temperature (room temperature)
Tmin 21.°C
H2O Water Desired temperature Tmax 36.°C
H2O Water Temperature difference ΔT 15 K
H2O Water Measurement 1 mass m 4 l
- Heating time Time t 600 s
η
Δ
⋅
⋅⋅
=
t
TcmP
Measurement 1
Solutions MPS®
PA Reactor station
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Solution 3.2: Reactor station – measurement and control
Name: Date:
3.2.1 Characteristics of the heating system medium Sheet 2 of 6
Symbol Designation Parameter Wert
3M1 Heater Power P 800 W
3M1 Heater Voltage U 8 VDC
3M1 Heater Efficiency factor η 0,8 ( 80%)
H2O Water Specific heat capacity c 4182 J/(kg*K)
H2O Water Minimum temperature (room temperature)
Tmin 21 °C
H2O Water Desired temperature Tmax 44 °C
H2O Water Temperature difference ΔT 23 K
H2O Water Measurement 2 mass m 4 l
- Heating
time- Time t 600 s
TminTΔTmax
cm
ηtPTΔ
+=
⋅
⋅⋅=
Measurement 2
Solutions MPS®
PA Reactor station
96 © Festo Didactic GmbH & Co. KG • MPS®
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Solution 3.2: Reactor station – measurement and control
Name: Date:
3.2.1 Characteristics of the heating system medium Sheet 3 of 6
Symbol Designation Parameter Value
3M1 Heater Power P 800 W
3M1 Heater Voltage V 8 VDC
3M1 Heater Efficiency factor η 0.8 ( 80%)
H2O Water Specific heat capacity c 4182 J/(kg*K)
H2O Water Minimum temperature (room temperature)
Tmin 19,5 °C
H2O Water Desired temperature Tmax 33 °C
H2O Water Temperature difference ΔT 12 K
H2O Water Measurement 3 mass m 8 l
- Heating time Time t 600 s
cm
ηtPTΔ
⋅
⋅⋅
=
Measurement 3
Solutions MPS®
PA Reactor station
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Solution 3.2: Reactor station – measurement and control
Name: Date:
3.2.1 Characteristics of the heating system medium Sheet 4 of 6
Time in s 10 20 30 40 50 100 200 300 400 500 600
Temperature
sensor signal
in V
2.1 2.1 2.1 2.1 2.1 2.2 2.4 2.7 3.0 3.3 3.6
Temperature
in °C. 21 21 21 21 21 22 24 27 30 33
36
4 l of water are heated.
Time in s 10 20 30 40 50 100 200 300 400 500 600
Temperature
sensor signal
in V
2.1 2.1 2.1 2.1 2.2 2.3 2.65 3.15 3.6 4.05 4.5
Temperature
in °C. 21 21 21 21.5 22 23 26.5 31.5 36 40.5
45
4 l of water are heated.
Time in s 10 20 30 40 50 100 200 300 400 500 600
Temperature
sensor signal
in V
1.9 1.9 1.95 2.0 2.0 2.1 2.3 2.55 2.75 3.0 3.25
Temperature
in °C. 19 19 19,5 20 20 21 23 25.5 27.5 30
32.5
8 l of water are heated.
Value table
measurement 1
Value table
measurement 2
Value table
measurement 3
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Solution 3.2: Reactor station – measurement and control
Name: Date:
3.2.1 Characteristics of the heating system medium Sheet 5 of 6
Characteristic curve of
The controlled systems
Solutions MPS®
PA Reactor station
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Solution 3.2: Reactor station – measurement and control
Name: Date:
3.2.1 Characteristics of the heating system medium Sheet 6 of 6
– How does the heating time change?
– Compare the characteristic curves and discuss the possible causes which result
in the different characteristic curves.
– How does the curve behaviour with double the quantity?
– How does the curve behave if the heating capacity is increased?
– How does the stirring influence the curve?
Comprehension questions
The speed of heating depends on the quantity of water and heating capacity.
The different values of the test parameters are the causes of the different characteristic curves. The fill
level quantity and the level of heating capacity considerably influence the test result. Thus, if the
heating capacity is doubled during the same test time, this results in temperature change almost
doubling, whereby if the quantity of water is doubled during the same test time and at the same
heating capacity the temperature change is virtually halved.
The stirring process ensures the water content is evenly heated during the test and also ensures a
virtually linear temperature curve.
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PA Reactor station
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Solution 3.2: Reactor station – measurement and control
Name: Date:
3.2.2 Logic operation Sheet 1 of 6
– Pushbutton S1, to heat water
– Pushbutton S2, to stirr water
– Pushbutton S3, to recirculate water
Solution has been realised using digital/analogue EasyPort and FluidSIM®
Setting condition for heater W301
P&I
diagram
symbol
Electr.
circuit
diagram
symbol
Address Logic
operation
Comment
- S1 - & Pushbutton
LS- 303 3B3 DI 2 & Sensor
(lower fill level at tank B301)
Resetting condition for heater W301
P&I
diagram
symbol
Electr.
circuit
diagram
symbol
Address Logic
operation
Comment
- S1 - ≥1 Not pushbutton
.
LS- 303 3B3 DI 2 ≥1 Not sensor
(lower fill level at tank B301)
Note
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PA Reactor station
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Solution 3.2: Reactor station – measurement and control
Name: Date:
3.2.2 Logic operation Sheet 2 of 6
Setting condition for stirrer R304
P&I
diagram
symbol
Electr.
circuit
diagram
symbol
Address Logic
operation
Comment
S2 & Pushbutton
LS- 303 3B3 DI 2 & Sensor
(lower fill level at tank B301)
Resetting condition for stirrer R304
P&I
diagram
symbol
Electr.
circuit
diagram
symbol
Address Logic
operation
Comment
S2 ≥1 Not pushbutton
LS- 303 3B3 DI 2 ≥1 Not sensor
(lower fill level at tank B301)
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Solution 3.2: Reactor station – measurement and control
Name: Date:
3.2.2 Logic operation Sheet 3 of 6
Setting condition for pump 301
P&I
diagram
symbol
Electr.
circuit
diagram
symbol
Address Logic
operation
Comment
S2 & Pushbutton
LS- 303 3B3 DI 2 & Sensor
(lower fill level at tank B301)
LS- 302 3B2 DI1 & Not sensor
(upper fill level at tank B301)
Resetting condition for pump 301
P&I
diagram
symbol
Electr.
circuit
diagram
symbol
Address Logic
operation
Comment
S2 ≥1 Not pushbutton
LS- 302 3B2 DI 1 ≥1 Sensor
(upper fill level at tank B301)
LS- 303 3B3 DI 2 ≥1 Not sensor
(lower fill level at tank B301)
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PA Reactor station
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Solution 3.2: Reactor station – measurement and control
Name: Date:
3.2.2 Logic operation Sheet 4 of 6
– Heater W301 on
– Stirrer R304 on
Logic diagram
Network 1
Network 2
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PA Reactor station
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Solution 3.2: Reactor station – measurement and control
Name: Date:
3.2.2 Logic operation Sheet 5 of 6
Pump P301
Network 3
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PA Reactor station
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Solution 3.2: Reactor station – measurement and control
Name: Date:
3.2.2 Logic operation Sheet 6 of 6
– Why must air in the piping system be avoided?
Comprehension questions
Air in the piping system prevents efficient operation of the system.
The pumps must be prevented from running dry as this will damage the pump.
Solutions MPS®
PA Reactor station
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Solution 3.2: Reactor station – measurement and control
Name: Date:
3.2.3 Determining the operating range and operating point of a controlled system Sheet 1 of 2
The solution has been realised using digital/analogue EasyPort and FluidLab®
-PA.
Determining the operating point of the temperature control system
Temperature sensor
Operating range of heater
Temperature
[˚C]
Output signal
measuring transducer [V]
Minimum measured
value Room temperature 2.0
Operating point 40 °C 4.0
Maximum measured
value 60 °C 6.0
Note
Solutions MPS®
PA Reactor station
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Solution 3.2: Reactor station – measurement and control
Name: Date:
3.2.3 Determining the operating range and operating point of a controlled system Sheet 2 of 2
– State the system conditions which could influence the operating range of the
heater and the measuring range of the sensor.
Comprehension questions
Different system conditions can influence the operating range of the heating element and temperature
sensor. One aspect is the medium itself and the quantity to be heated. This aspect is to be considered
if other liquids apart from water are to be heated. In this case the different temperature coefficients
need to be taken into consideration. Furthermore, the fill level should not fall below the lower fill level
sensor. This may damage the heating element and water tank.
A further influencing factor is the tank in which the medium is heated. Here temperature maintenance,
i.e. the heat dissipated to the environment, plays a role, whereby the efficiency factor of the heating
process depends on the insulation of the water tank.
To enable you to work more easily with the characteristic curve plotted, it is important that the liquid
is evenly heated. Therefore the stirrer should be in continuous operation throughout the
measurement test. In the case of stagnant media, heat is not evenly distributed but only around the
heating element and temperature may vary considerably in the various areas of the water tank.
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Solution 3.2: Reactor station – measurement and control
Name: Date:
3.2.4 Identifying a controlled system Sheet 1 of 2
Tt Tu
Tu
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PA Reactor station
© Festo Didactic GmbH & Co. KG • MPS®
PA 109
Solution 3.2: Reactor station – measurement and control
Name: Date:
3.2.4 Identifying a controlled system Sheet 2 of 2
– What is the value of the are time constants Tt and Tu obtained?
– Explain the system response?
Comprehension questions
Tt=7s
Tu=663s
The dead time in the example can be attributed to the fact that heating capacity is not fully available
at the heating element the moment it is switched on. It takes a while until the heating element outputs
the specified heating power to its environment. The medium between the heating element and
temperature sensor needs to be heated first and then the temperature sensor by the medium itself.
The first signal at the output is measured when the heated liquid reaches the sensor.
The slow system reaction results in a correspondingly high delay time. This depends on the quantity
and type of medium to be heated.
Evaluation
Solutions MPS®
PA Reactor station
110 © Festo Didactic GmbH & Co. KG • MPS®
PA
Solution 3.3: Reactor station – closed-loop control
Name: Date:
3.3.1 Two-position controller Sheet 1 of 2
The solution has been realised using digital/analogue EasyPort and FluidLab®
-PA.
Parameter Value
Setpoint value (w) at
operating point
0.4
Upper switching limit 2
Lower switching limit 2
Example for digital increase in heating using a two-position controller
Note
Solutions MPS®
PA Reactor station
© Festo Didactic GmbH & Co. KG • MPS®
PA 111
Solution 3.3: Reactor station – closed-loop control
Name: Date:
3.3.1 Two-position controller Sheet 2 of 2
– How does the system respond?
– Is a two-position controller suitable for this control task?
– Describe the control response.
Comprehension questions
The system responds with an increase in the water temperature. If the preset threshold values are
exceeded or fallen short of, the heating is switched on or off. Depending on the quantity of the liquid,
such switching intervals can involve long time spans.
Two-position controllers are used most frequently for temperature control. Unlike in the case of other
control examples, such as speed control, the actual value does not need to be continuously
monitored, since it is not crucial to set the temperature value exactly at the setpoint value. However, a
two-position controller can be used nevertheless for precision control by adjusting the hysteresis
appropriately. The switching frequency can thus be influenced according to threshold values
specified.
Solutions MPS®
PA Reactor station
112 © Festo Didactic GmbH & Co. KG • MPS®
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Solution 3.3: Reactor station – closed-loop control
Name: Date:
3.3.2 Closed-loop control using continuous-action controllers (P, I, PI) Sheet 1 of 5
The solution has been realised using digital/analogue EasyPort and FluidLab®
-PA.
Parameter Dimensionless
value
Value
˚C
Setpoint value (w) at operating
point
0.3 30
Note
Solutions MPS®
PA Reactor station
© Festo Didactic GmbH & Co. KG • MPS®
PA 113
Solution 3.3: Reactor station – closed-loop control
Name: Date:
3.3.2 Closed-loop control using continuous-action controllers (P, I, PI) Sheet 2 of 5
P controller
Example for Kp = 10
Implementation
Solutions MPS®
PA Reactor station
114 © Festo Didactic GmbH & Co. KG • MPS®
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Solution 3.3: Reactor station – closed-loop control
Name: Date:
3.3.2 Closed-loop control using continuous-action controllers (P, I, PI) Sheet 3 of 5
I controller
Example for Tn = 50
Implementation
Solutions MPS®
PA Reactor station
© Festo Didactic GmbH & Co. KG • MPS®
PA 115
Solution 3.3: Reactor station – closed-loop control
Name: Date:
3.3.2 Closed-loop control using continuous-action controllers (P, I, PI) Sheet 4 of 5
PI controller
Example for Kp = 5, Tn = 50
Implementation
Solutions MPS®
PA Reactor station
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Solution 3.3: Reactor station – closed-loop control
Name: Date:
3.3.2 Closed-loop control using continuous-action controllers (P, I, PI) Sheet 5 of 5
– How does the system respond with closed-loop control using a P controller?
– How does the system respond with closed-loop control using an I controller?
– How does the system respond with closed-loop control using PI controller?
– Which PI parameter pair results in the smallest overshoot and/or shortest
settling time?
Comprehension questions
P controller: The system responds relatively fast. The disadvantage is the remaining system deviation
at the output. A P controller cannot be operated without a system deviation, i.e. the manipulated
variable would also be zero.
I controller: The system responds very slowly to a setpoint change. The advantage is that the system
deviation is corrected to zero.
PI controller: The system responds relatively fast to a setpoint change. The system deviation is
completely corrected. The PI controller combines the positive properties of P and I controllers. The
P component ensure a fast step response; the I controller ensures that the system deviation is
corrected to the setpoint value.
Kp=5 and Tn=50 result in the smallest overshoot and shortest settling time.
Solutions MPS®
PA Reactor station
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Solution 3.3: Reactor station – closed-loop control
Name: Date:
3.3.3 Tuning method according to the rate of rise Sheet 1 of 4
Tt Tu
XΔ
tΔ
t
XV m a x
Δ
Δ=
Controller Kp Tn Tv Description
P HUMAX
PyTV
y%100K
⋅⋅
Δ⋅=
PI
HUMAX
P
yTV
yK
⋅⋅⋅
Δ⋅=
2.1
%100 UNTT ⋅= 3.3
PID
HUMAX
P
yTV
yK
⋅⋅⋅
Δ⋅=
83.0
%100 UNT2T ⋅=
UVTT ⋅= 5.0
ΔY= Maximum correcting range (100%)
YH= Specified step height
Solutions MPS®
PA Reactor station
118 © Festo Didactic GmbH & Co. KG • MPS®
PA
Solution 3.3: Reactor station – closed-loop control
Name: Date:
3.3.3 Manual tuning of controller parameters without knowledge of the system behaviour Sheet 2 of 4
– What are the values determined for Kp, Tn, Tv?
– What criteria are you using to evaluate your result?
Comprehension questions
Kp: P controller: 14.2
4.0*)11*017.0(
1=
PI controller: 78.1
4,0*)11*017.0(
83.0=
PID controller: 57,2
4.0*)11*017.0(
2,1=
Tn: PI controller: 3.3611*3.3 =
PID controller: 2211*0.2 =
Tv: PID controller: 5.511*5.0 =
On the basis of the preset parameters, different modes of behaviour can be established by the step response. With closed-loop control using a P controller, the manipulated variable is set to a predefined value. The manipulated variable decreases towards zero with decreasing system deviation. The system deviation is not fully corrected. In the case of a PI controller, the value of the manipulated variable increases to a certain point and then slowly decreases as in the case of a P controller. The maximum value of the output variable is above the setpoint value. A steady state can be assumed in this case since the cooling of the liquid is associated with long periods. The best result so far can be obtained with a PID controller, whereby the steady state is above the setpoint value as in the case of a PI controller, although the setpoint value is reached more quickly in the case of a PID controller.
Solutions MPS®
PA Reactor station
© Festo Didactic GmbH & Co. KG • MPS®
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Solution 3.3: Reactor station – closed-loop control
Name: Date:
3.3.3 Manual tuning of controller parameters without knowledge of the system behaviour Sheet 3 of 4
Example of P controller
Example of PI controller
Solutions MPS®
PA Reactor station
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Solution 3.3: Reactor station – closed-loop control
Name: Date:
3.3.3 Manual tuning of controller parameters without knowledge of the system behaviour Sheet 4 of 4
Example of PID controller
Solutions MPS®
PA Bottling station
© Festo Didactic GmbH & Co. KG • MPS® PA 121
Solution 4.1: Bottling station – system analysis and appraisal
Name: Date:
4.1.1 Designation of process components Sheet 1 of 2
3
1
2
4
Designation of process components
Solutions MPS®
PA Bottling station
122 © Festo Didactic GmbH & Co. KG •MPS®
PA
Solution 4.1: Bottling station – system analysis and appraisal
Name: Date:
4.1.1 Designation of process components Sheet 2 of 2
No. Designation Meaning or function
1 4M3
Conveyor motor
2 B401
Holding tank
3 B402
Metering tank
4 V403
Metering valve
5 4M4
Feed separator
You will find two different designations for the metering valve in the electrical circuit
diagram and flow diagram for the bottling station.
– Explain the difference.
Comprehension questions
The designation from the P&I diagram is a process designation. The process related functions in an
EMCS plan (EMCS = Electronic Measuring Control System) are known as EMCS points. The measured
variable or other input variables, their processing, direction of action and positional data should
follow from this designation.
An EMCS point consists of an EMCS circle and is designated with a code letter (A-Z) and a code
number. The code letters are entered in the upper section of the EMCS circle and the numbering in the
lower section. The sequence of code letters is established on the basis of the table "EMCS code letters
to DIN 19227".
The designation in an electrical circuit diagram describes an electrical function.
All electrical equipment of an MPS®
PA station is identified by means of equipment designations
according to the electrical circuit diagram. The designation of equipment in the electrical circuit
diagrams is effected according to the standard DIN/EN61346-2.
Designation of
process components
Solutions MPS®
PA Bottling station
© Festo Didactic GmbH & Co. KG •MPS®
PA 123
Solution 4.1: Bottling station – system analysis and appraisal
Name: Date:
4.1.2 Completing the P&I diagram Sheet 1 of 2
P&I diagram
Solutions MPS®
PA Bottling station
124 © Festo Didactic GmbH & Co. KG •MPS®
PA
Solution 4.1: Bottling station – system analysis and appraisal
Name: Date:
4.1.2 Completing the P&I diagram Sheet 2 of 2
Designation Meaning or function
LIC 403 Acoustic sensor
LS- Proximity sensor
LA+ Status, limit value alarm
P 401 Analogue pump
V Valve
– What is the difference between V401 and V402?
– What is the difference between the measuring point designations LA+ and LS+?
Comprehension questions
The valve V402 is a hand valve. V401 is a non-return valve. It allows a medium to flow in one direction
and inhibits it in the other direction.
The designations LA+ and LS+ differ with regard to their function within the station. Whereas both
sensors indicate the level of water in the tank, LA+ signals an error message. (often used as
Emergency-Stop.
Functional description
of components
Solutions MPS®
PA Bottling station
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PA 125
Solution4.1: Bottling station – system analysis and appraisal
Name: Date:
4.1.3 Completing the pneumatic circuit diagram Sheet 1 of 2
Pneumatic circuit diagram
Solutions MPS®
PA Bottling station
126 © Festo Didactic GmbH & Co. KG •MPS®
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Solution4.1: Bottling station – system analysis and appraisal
Name: Date:
4.1.3 Completing the pneumatic circuit diagram Sheet 2 of 2
Symbol Meaning or function
Silencer
5/2-way valve
Double-acting cylinder
– What does the designation 5/2-way valve mean?
– What is the function of a silencer?
Comprehension questions
The 5/2-way valve has 5 ports and 2 switching positions. One port is intended for the supply of
compressed air. The remaining 4 ports are for the connection of working and exhaust lines. Depending
on design, the valve can be either pneumatically actuated via pilot air or electronically actuated.
The silencer reduces the noise levels of escaping air.
Functional description of
pneumatic components
Solutions MPS®
PA Bottling station
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PA 127
Solution 4.1: Bottling station – system analysis and appraisal
Name: Date:
4.1.4 Determining the technical data of a system Sheet 1 of 2
Component Designation Function Characteristics
Pump P401 Pumps water into
mixing tank
Voltage [V] 24 V
Electric power [W] 26 W
Max. throughput [l/min] 9 l/min
Acoustic
sensor
4B1
Measures the level
of water.
Measuring principle:
An acoustic signal is generated and the
reflection time is measured. This signal is
converted into a voltage signal
Measuring range [mm] 300-50 mm
Sensor signal [V] 0-10 V
Geared
motor -
Transports bottles
to the filling
position
Voltage [V] 24 V
Nominal current[A] 1.5 A
Speed of
drive shaft [r.p.m.] 65 r.p.m.
Limit switch
top
4B2
Status, upper limit
value
in Tank B401
Filling quantity up to contact [l] 6 l
Type (n. open/n. closed contact)
n. open contact
Limit switch
bottom
4B3
Status, lower limit
value
in tank B401
Filling quantity up to contact [l] 2 l
Type (n. open/n. Closed contact)
n. open contact
Technical data
Solutions MPS®
PA Bottling station
128 © Festo Didactic GmbH & Co. KG •MPS®
PA
Solution 4.1: Bottling station – system analysis and appraisal
Name: Date:
4.1.4 Determining the technical data of a system Sheet 2 of 2
– What is the voltage supplied by the acoustic sensor for a filling quantity of 2l?
Comprehension questions
2.5l � 10V
0l � 0V
2l � 8V
Solutions MPS®
PA Bottling station
© Festo Didactic GmbH & Co. KG •MPS®
PA 129
Solution 4.1: Bottling station – system analysis and appraisal
Name: Date:
4.1.5 Drawing up the allocation list Sheet 1 of 3
Symbol EasyPort /
Simubox
address
PLC address Description Check
4B1 DI 0 I 0.0 Acoustic sensor B402
4B2 DI 1 I 0.1 Holding tank B401 top
4B3 DI 2 I 0.2 Holding tank B401 bottom
4B4 DI 3 I 0.3 Bottle at start of conveyor
4B5 DI 4 I 0.4 Bottle being filled
4B6 DI 5 I 0.5 Bottle at end of conveyor
Not busy DI 6 I 0.6 Not busy
4PA_Free DI 7 I 0.7 Receiver PA downstream station
free
Symbol EasyPort /
Simubox
address
PLC address Description Check
4PV1 AI0 EW256 Actual value X (fill level)
Allocation list of
digital inputs
Allocation list of
analogue inputs
Solutions MPS®
PA Bottling station
130 © Festo Didactic GmbH & Co. KG •MPS®
PA
Solution 4.1: Bottling station – system analysis and appraisal
Name: Date:
4.1.5 Drawing up the allocation list Sheet 2 of 3
Symbol EasyPort /
Simubox
address
PLC address Description Check
4M1 DO 0 O 0.0 Pump P401 on
4M2 DO 1 O 0.1 Filling valve On
4M3 DO 2 O 0.2 Conveyor motor on
4M4 DO 3 O 0.3 Feed separator active
Not busy DO 4 O 0.4 Not busy
Not busy DO 5 O 0.5 Not busy
Not busy DO 6 O 0.6 Not busy
4PA_Busy DO 7 O 0.7 Sender PA station busy
Symbol EasyPort /
Simubox
address
PLC address Description Check
4CO1 AO 0 AW256 Manipulated variable Y, (pump
P401)
Allocation list of
digital outputs
Allocation list of
analogue outputs
Solutions MPS®
PA Bottling station
© Festo Didactic GmbH & Co. KG •MPS®
PA 131
Solution 4.1: Bottling station – system analysis and appraisal
Name: Date:
4.1.5 Drawing up the allocation list Sheet 3 of 3
– What particular situation should be considered in the bottling station if the
analogue final control element (pump) is to be digitally controlled?
Comprehension questions
To enable digital control of the analogue final control element (pump), the bridge in the connection
board must be converted to „digital“.
Solutions MPS®
PA Bottling station
132 © Festo Didactic GmbH & Co. KG •MPS®
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Solution 4.2: Bottling station – measurement and control
Name: Date:
4.2.1 Characteristics of the metering tank/pump system Sheet 1 of 4
The solution has been realised using digital/analogue EasyPort and FluidLab®
-PA.
Voltage at
pump
control in V
0.00 0.50 1.00 1.50 2.00 2.0 3.00 3.50 4.00 4.50 5.00
Acoustic
sensor
signal in V
0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.2 3.3
Fill level
in l. 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.18 0.5
Voltage at
pump
control in V
5.50 6.00 6.50 7.00 7.50 8.00 8.50 9.00 9.50 10.00
Acoustic
sensor in V 6.7 max max max max max max max max max
Fill level
in l. 1.5 Max max max max max max max max max
Closed drain valve.
Note
Value table
closed drain valve
Solutions MPS®
PA Bottling station
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Solution 4.2: Bottling station – measurement and control
Name: Date:
4.2.1 Characteristics of the metering tank/pump system Sheet 2 of 4
Voltage at
pump
control in V
0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00
Acoustic
sensor
signal in V
0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
Fill level in l. 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
0.0
Voltage at
pump
control in V
5.50 6.00 6.50 7.0 7.50 8.00 8.50 9.00 9.50 10.00
Acoustic
sensor
signal in V
0.0 0.0 0.0 2.2 4.6 6.9 9.4 max max max
Fill level
in l. 0.0 0.0 0.0 0.33 0.87 1.56 2.33 max max
max.
Drain valve fully open.
Value table
open drain valve
Solutions MPS®
PA Bottling station
134 © Festo Didactic GmbH & Co. KG •MPS®
PA
Solution 4.2: Bottling station – measurement and control
Name: Date:
4.2.1 Characteristics of the metering tank/pump system Sheet 3 of 4
The solution has been realised using digital/analogue EasyPort and FluidLab®
-PA.
Example for closed drain valve
Red characteristic curve: 5.0 V
Blue characteristic curve: 5.5 V
Green characteristic curve: 6.0 V
Note
Solutions MPS®
PA Bottling station
© Festo Didactic GmbH & Co. KG •MPS®
PA 135
Solution 4.2: Bottling station – measurement and control
Name: Date:
4.2.1 Characteristics of the metering tank/pump system Sheet 4 of 4
– Compare the characteristic curves and discuss the possible causes leading to
their differences.
– Explain the reasons for the system behaviour at low voltages.
Comprehension questions
The back pressure in the metering tank is constantly increasing, the higher water level rises and
the pump has to counteract this. Depending on the rate of delivery of the pump a steady state
occurs where the fill level remains virtually constant.
The pump only pumps water into the metering tank as of approx. 4.5V if the drain valve is closed,
and as of 7V if the drain valve is fully open.
Note: The bend in the characteristic curve at 0.5 l can be attributed to the shape of the metering
tank. In the lower section, the volume is not linear in relation to the delivery height.
Solutions MPS®
PA Bottling station
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Solution 4.2: Bottling station – measurement and control
Name: Date:
4.2.2 Logic operation Sheet 1 of 6
– Pushbutton S1, pumps water
– Pushbutton S2, fills bottles
– Pushbutton S3, transports bottles
The solution has been realised using digital/analogue EasyPort and FluidSIM®
.
Setting condition for pump P401
P&I
diagram
symbol
Electr.
circuit
diagram
symbol
Address Logic
operation
Comment
- S1 - & Pushbutton
LS- 202 4B3 DI 2 & Sensor
(lower fill level at tank B401)
Resetting condition for pump V401
P&I
diagram
symbol
Electr.
circuit
diagram
symbol
Address Logic
operation
Comment
- S1 - ≥1 Not pushbutton
- S2 - ≥1 Pushbutton
LS- 202 4B3 DI 2 ≥1 Not sensor
(lower fill level at tank B401)
Note
Solutions MPS®
PA Bottling station
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Solution 4.2: Bottling station – measurement and control
Name: Date:
4.2.2 Logic operation Sheet 2 of 6
Setting condition for valve V403
P&I
diagram
symbol
Electr.
circuit
diagram
symbol
Address Logic
operation
Comment
- S2 - & Pushbutton
- 4B5 DI4 & Diffuse sensor
(bottle at filling position)
Resetting condition for valve V402
P&I
diagram
symbol
Electr.
circuit
diagram
symbol
Address Logic
operation
Comment
- S1 - ≥1 Pushbutton
- S3 - ≥1 Pushbutton
- S2 - ≥1 Not pushbutton
- 4B5 DI4 ≥1 Not diffuse sensor
(bottle at filling position)
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PA Bottling station
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Solution 4.2: Bottling station – measurement and control
Name: Date:
4.2.2 Logic operation Sheet 3 of 6
Setting condition for conveyor motor 4M3
P&I
diagram
symbol
Electr.
circuit
diagram
symbol
Address Logic
operation
Comment
- S3 - & Pushbutton
- 4B4 DI3 & Diffuse sensor
(bottle at start of conveyor)
Resetting condition for conveyor motor 4M3
P&I
diagram
symbol
Electr.
circuit
diagram
symbol
Address Logic
operation
Comment
- 4B5 DI4 -
Diffuse sensor
(bottle at filling position)
Solutions MPS®
PA Bottling station
© Festo Didactic GmbH & Co. KG •MPS®
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Solution 4.2: Bottling station – measurement and control
Name: Date:
4.2.2 Logic operation Sheet 4 of 6
– Pump P401 on
– Metering valve V403 on
Logic diagram
Network 1
Network 2
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PA Bottling station
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Solution 4.2: Bottling station – measurement and control
Name: Date:
4.2.2 Logic operation Sheet 5 of 6
Conveyor motor 4M3 on
Network 3
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PA Bottling station
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PA 141
Solution 4.2: Bottling station – measurement and control
Name: Date:
4.2.2 Logic operation Sheet 6 of 6
– Why should air in the piping system be avoided?
Comprehension questions
Air in the piping system prevents correct operation of the system.
Pumps must be prevented from running dry as this will cause damage.
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Solution 4.2: Bottling station – measurement and control
Name: Date:
4.2.3 Determining the operating range and operating point of a controlled system Sheet 1 of 1
Determining the operating point of the fill level control system
Acoustic sensor
operating range of pump
Manipulated
variable of pump
P201 [V]
Fill level
[l] Output signal [V]
Minimum measured
value 5 0.5 3.3
Operating point 5.5 1.5 6.6
Maximum measured
value 6 2.5 9.9
– State the system conditions which could influence the operating range of the
pump and measuring range of the sensor.
– Where does the linear range of the controlled system begin?
Comprehension questions
The position of the drain valve, piping system, mounting position of the sensor level, whether filling is
from the bottom or the top
The linear range of the controlled system begins at 0.5 l.
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PA Bottling station
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Solution 4.2: Bottling station – measurement and control
Name: Date:
4.2.4 Identifying a controlled system Sheet 1 of 2
63%
Ts
Example of the calculation of the time constant Ts
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Solution 4.2: Bottling station – measurement and control
Name: Date:
4.2.4 Identifying a controlled system Sheet 2 of 2
– What is the value determined for the system gain Ks?
– What type of system is it, i.e. of what order?
– What is/are the time constant(s) obtained?
– Explain the reasons for the system behaviour?
Comprehension questions
System gain Ks= 0.867
PT1, 1st order system.
Ts= 59.5s
A characteristic of PT1 controlled systems is to „run on“ to a final steady-state value when the energy
supplied = dissipated energy; in this case, the pump capacity against the pressure of the metering
tank.
Solutions MPS®
PA Bottling station
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Solution 4.2: Bottling station – measurement and control
Name: Date:
4.2.5 Inflow and outflow behaviour of the metering tank Sheet 1 of 6
Pump voltage in V
Fill level [l] Time [s] Fill level [l] Time [s]
0.5 4.0 1.8 15.25
0.6 5.2 1.9 16.0
0.7 6.2 2.0 17.0
0.8 6.7 2.1 17.75
0.9 8.0 2.2 18.5
1.0 8.5 2.3 19.5
1.1 9.0 2.4 20.25
1.2 10.25 2.5 21.00
1.3 11.25 2.6 -
1.4 12.0 2.7 -
1.5 13.0 2.8 -
1.6 13.75 2.9 -
1.7 14.5 3.0 -
Measurement 1
drain valve closed,
pump on
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PA Bottling station
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Solution 4.2: Bottling station – measurement and control
Name: Date:
4.2.5 Inflow and outflow behaviour of the metering tank Sheet 2 of 6
Pump voltage in V 0 V
Fill level [l] Time [s] Fill level [l] Time [s]
3.0 - 1.7 9.6
2.9 - 1.6 10.8
2.8 - 1.5 12.0
2.7 - 1.4 13.2
2.6 - 1.3 14.4
2.5 0 1.2 15.6
2.4 1,5 1.1 17.0
2.3 2,6 1.0 18.2
2.2 3,8 0.9 19.4
2.1 5,0 0.8 20.6
2.0 6,2 0.7 21.8
1.9 7,4 0.6 23.2
1.8 8,6 0.5 24.6
Measurement 2
drain valve open,
pump off
Solutions MPS®
PA Bottling station
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Solution 4.2: Bottling station – Messen und Steuern
Name: Date:
4.2.5 Inflow and outflow behaviour of the metering tank Sheet 3 of 6
Pump voltage in V
Fill level [l] Time [s] Fill level [l] Time [s]
0.5 10 1.8 37.5
0.6 11 1.9 41
0.7 13 2.0 44
0.8 15 2.1 47
0.9 17 2.2 50
1.0 19 2.3 54
1.1 21 2.4 57.5
1.2 23 2.5 61.5
1.3 25 2.6 -
1.4 27 2.7 -
1.5 29.5 2.8 -
1.6 32.5 2.9 -
1.7 35 3.0 -
Measurement 3
drain valve open,
pump on
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Solution 4.2: Bottling station – measurement and control
Name: Date:
4.2.5 Inflow and outflow behaviour of the metering tank Sheet 4 of 6
Example of inflow behaviour – filling from the bottom with drain valve closed
Example for outfow behaviour
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Solution 4.2: Bottling station – measurement and control
Name: Date:
4.2.5 Inflow and outflow behaviour of the metering tank Sheet 5 of 6
Example for inflow behaviour – filling from the bottom with drain valve open
Special solution:
Example for inflow behaviour – filling from the top with drain valve closed
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Solution 4.2: Bottling station – measurement and control
Name: Date:
4.2.5 Inflow and outflow behaviour of the metering tank Sheet 6 of 6
– How does the curve progress in measurement 1?
– What is the difference between the curve progressions of measurements 1
and 3?
– Why does the curve progression of measurement 2 exhibit a decaying behaviour?
Comprehension questions
A linear behaviour is evident in measurement 1, provided that the pump capacity is sufficiently high.
In the case of measurement 3, the filling process takes longer until the metering tank is full and a
decaying behaviour is also apparent. This can be attributed to the fact that the pump not only has to
counteract the water pressure in the metering tank, but in addition also has to cope with the drain
quantity rate.
Measurement 2 exhibits linear as opposed to decaying behaviour. The cause of this is that the level in
the metering tank is not sufficient to illustrate this. The slightly different progression from 0.5 l can be
attributed to the shape of the metering tank.
In the case of measurement 3, the open drain valve prevents a rapid rise of liquid in the metering tank
since part of the liquid delivered flows back into the holding tank via the open valve. However, since
the outflow via the valve is less than the inflow via the pump, part of the liquid reaches the metering
tank and the fill level gradually increases. If the system moves into its steady state (fill level does not
rise further), the liquid is pumped back virtually directly into the holding tank via the drain valve, since
the set pump performance is no longer sufficient to overcome the water pressure in the metering tank.
The water pressure practically „seals“ the metering tank.
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Solution 4.3: Bottling station – closed-loop control
Name: Date:
4.3.1 Two-position controller Sheet 1 of 2
The solution has been realised using digital/analogue EasyPort and FluidLab®
-PA.
Parameter Value
Setpoint value (w) at
operating point
0.67
Upper switching value 0.1
Lower switching value 0.1
Example of two-position controller
Note
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Solution 4.3: Bottling station – closed-loop control
Name: Date:
4.3.1 Two-position controller Sheet 2 of 2
– How does the system respond?
– State some typical areas of application of a two-position controller.
– Describe the control behaviour.
Comprehension questions
With this controller type, the manipulated variable can only assume two defines states, in our example
0V and 10V(Vmax). The output of the controller switches to and fro between these two states
depending on whether the upper or lower threshold value is exceeded. In our example the
manipulated variable increases to its maximum value at the moment of switch-on until the controlled
variable reaches the upper threshold value. The pump is switched off and the controlled variable now
decreases until the lower threshold value is reached when the reverse process takes over.
The two-position controller is particularly suitable for the control of systems with large time constants.
Other areas of application are for example the control of a reservoir (compressor), the control of room
temperature or humidity.
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Solution 4.3: Bottling station – closed-loop control
Name: Date:
4.3.2 Closed-loop control using continuous-action controllers (P, I, PI) Sheet 1 of 5
The solution has been realised using digital/analogue EasyPort and FluidLab®
-PA.
Parameter Dimensionless
value
Value
l
Setpoint value (w) at operating
point
0.67 1.51
Note
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Solution 4.3: Bottling station – closed-loop control
Name: Date:
4.3.2 Closed-loop control using continuous-action controllers (P, I, PI) Sheet 2 of 5
P controller
Example for Kpr = 10
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Solution 4.3: Bottling station – closed-loop control
Name: Date:
4.3.2 Closed-loop control using continuous-action controllers (P, I, PI) Sheet 3 of 5
I controller
Example for Tn = 10
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Solution 4.3: Bottling station – closed-loop control
Name: Date:
4.3.2 Closed-loop control using continuous-action controllers (P, I, PI) Sheet 4 of 5
PI controller
Example for Kpr = 2, Tn = 5
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Solution 4.3: Bottling station – closed-loop control
Name: Date:
4.3.2 Closed-loop control using continuous-action controllers (P, I, PI) Sheet 5 of 5
– How does the system respond with closed-loop control using a P controller?
– How does the system react with closed-loop control using an I controller?
– How does the system react with closed-loop control using a PI controller?
– Which PI parameter pair results in the smallest overshoot and/or shortest
settling time?
– Which controller is suitable for this controlled system if the system deviation is to
be corrected to 0?
Comprehension questions
P controller: The system responds relatively fast to the input step. The disadvantage is the remaining
system deviation. If the Kp selected is too large, the system starts to oscillate.
I controller: The system responds very slowly to a setpoint change. The advantage is that the system
deviation is corrected to zero after a certain period. If the Tn is too small, the system becomes limit
stable? or instable.
PI controller: The system responds relatively fast to a setpoint change. The system deviation is
completely corrected. The PI controller combines the positive characteristics of a P and I controller.
The P component ensures a fast step response, the I controller ensures that the system deviations are
corrected to the setpoint value.
Kpr=2 and Tn =5 result in the smallest overshoot.
Both a PI controller and an I controller would be suitable. The PI controller reaches the settling time
fastest.
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Solution 4.3: Bottling station – closed-loop control
Name: Date:
4.3.3 Controller tuning according to Chien-Hrones-Reswick Sheet 1 of 2
The solution has been realised using digital/analogue EasyPort and FluidLab®
–PA.
Tu
Tg
Note
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Solution 4.3: Bottling station – closed-loop control
Name: Date:
4.3.3 Controller tuning according to Chien-Hrones-Reswick Sheet 2 of 2
– Which controller have you selected and why?
– What are the values determined for Kp, Tn, Tv?
– What criteria do you use to evaluate your result?
Comprehension questions
Kp: P controller: 1.2
1
7*
1
3.0*
3.0==
Ts
Tg
Ks
PI controller: 45.2
1
7*
1
35.0*
35.0==
Ts
Tg
Ks
PID controller: 2.4
1
7*
1
6.0*
6.0==
Tu
Tg
Ks
Tn: PI controller: 2.11*2.1*2.1 ==Tu
PID controller: Tg= 7
Tv: PID controller: 5.01*5.0*5.0 ==Tu
With the preset parameters, various behaviours can be observed from the step response. In the case
of closed-loop control using a P controller, the output signal is relatively quick in the steady state,
although the system deviation cannot be corrected. If the test is carried out using a PI controller, a
slight overshoot can be observed. The setpoint value is reached quickly without remaining system
deviation. The PID controller corrects the system deviations the fastest. A steady state is obtained
after a few small overshoots.
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