Workbook

EduKit PA
Project kit
Process automation

With CD-ROM

Festo Didactic
563971 EN
Use for intended purpose

This system and the workbook have been developed and produced exclusively for training and further
education in the field of process automation and technology. The respective training companies and/or
trainers must ensure that all trainees observe the safety precautions which are described in the
accompanying manuals.
Festo Didactic hereby excludes any and all liability for damages suffered by trainees, the training company
and/or any third parties, which occur during use of the system in situations which serve any purpose other
than training and/or vocational education, unless such damages have been caused by Festo Didactic due to
malicious intent or gross negligence.

Order no. 563971

Revision level: 04/2009
Authors: Bernhard Schellmann, Hans Kaufmann
Editors: Jürgen Helmich, Klaus Kronberger
Graphic design: Doris Schwarzenberger
Layout: 05/2009

© Festo Didactic GmbH & Co. KG, 73770 Denkendorf, 2013

Internet: www.festo-didactic.com
e-mail: did@de.festo.com

© Adiro Automatisierungstechnik GmbH, 73734 Esslingen, 2013

Internet: www.adiro.com
E-mail: info@adiro.com

The purchaser shall receive a single right of use which is non-exclusive, non-time-limited and limited
geographically to use at the purchaser's site/location as follows.
The purchaser shall be entitled to use the work to train his/her staff at the purchaser's site/location and
shall also be entitled to use parts of the copyright material as the basis for the production of his/her own
training documentation for the training of his/her staff at the purchaser's site/location with
acknowledgement of source and to make copies for this purpose. In the case of schools/technical colleges
and training centres, the right of use shall also include use by school and college students and trainees at
the purchaser's site/location for teaching purposes.
The right of use shall in all cases exclude the right to publish the copyright material or to make this available
for use on intranet, Internet and LMS platforms and databases such as Moodle, which allow access by a
wide variety of users, including those outside of the purchaser's site/location.
Entitlement to other rights relating to reproductions, copies, adaptations, translations, microfilming and
transfer to and storage and processing in electronic systems, no matter whether in whole or in part, shall
require the prior consent of Festo Didactic GmbH & Co. KG.
Table of contents

Introduction ______________________________________________________________________________9
Training content ____________________________________________________________________5
Learning objectives__________________________________________________________________6
References to German school syllabi and vocations________________________________________6
Obligations of the trainees __________________________________________________________ 11
Risks associated with the modular production system ___________________________________ 11
Guarantee and liability _____________________________________________________________ 11
Use for intended purpose ___________________________________________________________ 12
Safety precautions ________________________________________________________________ 12
Transport ________________________________________________________________________ 14
Unpacking _______________________________________________________________________ 14
Scope of delivery _________________________________________________________________ 14
Visual inspection _________________________________________________________________ 14
Maintenance _____________________________________________________________________ 15
Updates _________________________________________________________________________ 15

Part A – Plant construction

1. Process description _______________________________________________________________ A-3

2. Planning ________________________________________________________________________ A-9
3. Installation _____________________________________________________________________ A-43
4. Commissioning __________________________________________________________________ A-47
5. Marketing and sales ______________________________________________________________ A-51
6. Evaluation of learning objectives for plant construction _________________________________ A-55

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

closed-loop control

1. Manual measurement______________________________________________________________ B-3

2. Manual open-loop control _________________________________________________________ B-13
3. Manual closed-loop control ________________________________________________________ B-37
4. Evaluation of learning objectives for manual measuring, open-loop
and closed-loop control ___________________________________________________________ B-47

© Festo Didactic GmbH & Co. KG 3

Table of contents

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

closed-loop control

1. Basic principles ___________________________________________________________________ C-3

2. Automated measurement__________________________________________________________ C-13
3. Automated open-loop control ______________________________________________________ C-25
4. Automated closed-loop control _____________________________________________________ C-41
5. Evaluation of learning objectives for automated measurement, open-loop
and closed-loop control ___________________________________________________________ C-59

Part D1 – Plant construction with solutions

1. Process description ______________________________________________________________ D1-3

2. Planning _______________________________________________________________________ D1-9
3. Installation ____________________________________________________________________D1-43
4. Commissioning _________________________________________________________________D1-47
5. Marketing and sales _____________________________________________________________D1-51
6. Evaluation of learning objectives for plant construction ________________________________D1-55

Part D2 – Practice-based learning: manual measurement, open-loop and

closed-loop control with solutions

1. Manual measurement_____________________________________________________________ D2-3

2. Manual control _________________________________________________________________D2-13
3. Manual control _________________________________________________________________D2-37
4. Evaluation of learning objectives for manual measurement, open-loop
and closed-loop control __________________________________________________________D2-47

Part D3 – Practice-based learning: automated measurement, open-loop and

closed-loop control with solutions

1. Basic principles __________________________________________________________________ D3-3

2. Automated measurement_________________________________________________________D3-13
3. Automated open-loop control _____________________________________________________D3-25
4. Automated closed-loop control ____________________________________________________D3-41
5. Evaluation of learning objectives for automated measurement, open-loop
and closed-loop control __________________________________________________________D3-59

4 © Festo Didactic GmbH & Co. KG

Introduction

Festo Didactic’s process automation and technology learning system is aimed at various educational
backgrounds and vocational requirements. The systems and stations included with the modular production
system for process automation (MPS® PA) facilitate training and vocational education which is based on
real-life company situations. The hardware comprises industrial components specifically prepared for this
purpose.

The process automation project kit provides you with a suitable, practical system with which you can convey
key competencies including:
 Social
 Technical
 Procedural

In addition, teamwork, willingness to cooperate and organisational skills are also part of the training.
The learning modules focus on realistic project phases. These include:
 Planning
 Installation
 Wiring
 Commissioning
 Operation
 Open-loop control technology
 Closed-loop control technology
 Maintenance
 Troubleshooting

Training content
The following subject areas are covered:
 Mechanical
– Mechanical layout of a system
 Process engineering
– Read and prepare flowcharts and documentation
– Piping connections for process engineering components
– System analysis
 Electrical engineering
– Create electrical circuit diagrams
– Correct wiring of electrical components
 Sensor technology
– Correct use of sensors
– Measurement of non-electrical, process engineering and control technology quantities
 Commissioning
– Initial commissioning of a process system
– Initial commissioning of a controlled system

© Festo Didactic GmbH & Co. KG 5

Introduction

 Open-loop control technology

– Controlling actuators
– Relay circuits
 Closed-loop control technology
– Fundamentals of closed-loop control technology
– Expansion of measuring chains into closed-loop control circuits
– Analysis of regulated systems
– Use of regulators
 Troubleshooting
– Systematic troubleshooting of a process system
– Inspection, maintenance and servicing of process systems

Learning objectives
 Become familiar with the setup and the mode of operation of the fill-level system.
 Read and expand flow diagrams.
 Read and expand simple electrical circuit diagrams.
 Become familiar with the setup and mode of operation of a pressure gauge.
 Become familiar with the setup and mode of operation of a pump.
 Become familiar with the setup and mode of operation of a flow sensor.
 Record and analyse characteristic curves.
 Become familiar with the terms “open-loop control” and “closed-loop control”.
 Become familiar with the concepts of discontinuous control (2-step control) and continuous control.
 Become familiar with the essential work steps in the field of plant construction, from planning to
operation.

References to German school syllabi and vocations

Type of school Planning, engineering, Commissioning, Open-loop control Closed-loop control

assembly, marketing production system technology technology

Secondary schools, 10th grade SU 2 SU 2

Vocational secondary schools, SU 2, 4 SU 2, 4 SU 2, 4 SU 4

9th grade

Vocational secondary schools, SU 1 SU 1 SU 2 SU 2

10th grade

SU = syllabus unit

6 © Festo Didactic GmbH & Co. KG

 Introduction

Vocations according to Planning, engineering, Commissioning, Control technology Regulation

learning content assembly, marketing production system technology

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

System technician, sanitary, LC 5, 6 LC 7 LC 10 LC 10

heating and air-conditioning

Chemical laboratory technician LC 12 LC 12

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

Electronics technician LC 6 LC 3 LC 7

Electronics technician for LC 10 LC 10 LC 6, 7 LC 10

automation

Qualified personnel for water LC 4, 13 LC 4 LC 4, 14 LC 4, 14

supply technology

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

Industry mechanic LC 6 LC 13

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

Pharmaceuticals technician LC 7 LC 7

Process technician for glass LC 9 LC 13

technology

LC = learning content

Basic stage
Introduction

Notes for the

Training content Syllabi/vocations Diagram Room layout
operating company

Plant manufacturing

1. Process 5. Marketing
2. Planning 3. Installation 4. Commissioning
description and sales

Practice based lerning:

manual MSR

Advanced level
Practice based learning:
automated MSR

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

© Festo Didactic GmbH & Co. KG 7

Introduction

Project module
EduKit PA

Basic stage Setup varia

2 tanks
With one tank, With two tanks,
e.g. recirculation e.g. fill-level
EduKit PA
control panel EduKit PA
control panel
Pressure gauge
Pressure gauge
Float
Float
Teachware

Systainer

Intermediate level Setup varia

EduKit PA
I/O board With one tank, With two tanks,
e.g. recirculation e.g. fill-level

Binary sensors, EduKit PA

e.g. float switch I/O board

Actuation via
Analogue sensors,
e.g. ultrasonic sensor EasyPort

PLC
Actuators, e.g.
2-way ball valve
with pneumatic EduKit PA
actuation control panel

Pressure sensor

Accessories Flow sensor

Ultrasonic sensor
Power supply unit
Process actuator
EasyPort
Solenoid valve
PLC

Fluid Lab®-PA

WBT-PA (in preparation)

Hardware flow chart, EduKit PA process automation project kit

8 © Festo Didactic GmbH & Co. KG

 Introduction

Sample room layout

© Festo Didactic GmbH & Co. KG 9

Introduction

Classification into groups within the product range

Important note
The fundamental prerequisites for the safe use and trouble-free operation of the EduKit PA project kit
include knowledge of basic safety precautions and safety regulations.
This workbook includes the most important instructions for the safe use of the EduKit PA project kit. In
particular, the safety precautions must be adhered to by all persons working with the EduKit PA project
kit.
Furthermore, all pertinent rules and regulations for the prevention of accidents, which are applicable at
the respective location of use, must be adhered to.

10 © Festo Didactic GmbH & Co. KG

 Introduction

Obligations of the operating company

The operating company undertakes to allow only those persons to work with the EduKit PA project kit who:
 are familiar with the basic regulations regarding work safety and accident prevention and have been
instructed in the use of the EduKit PA project kit, and
 have read and understood the section concerning safety and the safety precautions.
 In the event that the EduKit PA project kit is not monitored by the operating company itself, an
appropriate person must be designated who, on the basis of his technical qualifications, is capable of
evaluating the functionality of the station as well as the dangers which result therefrom, for himself and
all trainees.

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

Obligations of the trainees

All persons who have been entrusted to work with the EduKit PA project kit undertake to complete the
following steps before beginning work:
 Read the section on safety and the safety precautions in this manual
 Familiarise themselves with basic regulations regarding work safety and accident prevention
 Familiarise themselves with the specific dangers associated with compressed air, without which the
equipment would not be feasible, and accordingly ensure their own safety
 Disconnect the station from mains power when cleaning work or inspections are requested by the
person in charge.

Risks associated with the modular production system

The EduKit PA project kit is laid out in accordance with the latest state-of-the-art technology as well as
recognised safety rules. Nevertheless, life and limb of the user and third parties may be at risk and the
machine or other property may be damaged during its use.
The EduKit PA project kit may only be used:
 For its intended purpose
 When its safety functions are in perfect order

Faults which may impair safety must be eliminated immediately!

Guarantee and liability

Our “general terms and conditions of sale and delivery” always apply. These are made available to the
operating company no later than upon conclusion of the sales contract. Guarantee and liability claims
resulting from personal injury and/or property damage are excluded if they can be traced back to one or
more of the following causes:
 Use of EduKit PA project kit for other than its intended purpose
 Incorrect assembly, commissioning and/or operation of EduKit PA project kit

© Festo Didactic GmbH & Co. KG 11

Introduction

 Use of the EduKit PA project kit with defective safety equipment or with incorrectly attached or non-
functioning safety and protective equipment
 Non-compliance with instructions included in the manual with regard to transport, storage, assembly,
commissioning, operation, maintenance and setup of the EduKit PA project kit
 Inadequate monitoring of system components which are subject to wear
 Improperly executed repairs
 Disasters resulting from the influence of foreign bodies and acts of God

Festo Didactic hereby excludes any and all liability for damages suffered by trainees, the training company
and/or any third parties, which occur during use of the system in situations which serve any purpose other
than training and/or vocational education, unless such damages have been caused by Festo Didactic due to
malicious intent or gross negligence.

Use for intended purpose

This station has been developed and manufactured exclusively for training and vocational education in the
fields of automation and technology. The respective training companies and/or trainers must ensure that all
trainees observe the safety precautions which are described in the accompanying manuals.

Use for intended purpose also encompasses:

 Compliance with all instructions included in the manual
 Completion of inspection and maintenance tasks

Safety precautions

General
 Trainees should only work at the station under the supervision of a trainer.
 Observe specifications included in the data sheets for the individual components and in particular all
safety instructions!
 Teachers and trainers must be capable of assessing the experiments they supervise or execute with
electrical energy, as well as any potential danger using their knowledge and training (e.g. with regard to
their own specialty, regulations and standards).

Electrical
 Electrical connections must only be established and interrupted in the absence of voltage!
 Use low-voltage only (max. 24 V DC).
 Correct polarity must be assured when connecting certain electrical components, especially sensors.
These components may be destroyed in the event of polarity reversal or short-circuiting.
 Electrical components are pre-wired at the factory, and are mounted onto an H-rail for direct attachment
to the rectangular profile. Alternatively, they can be shipped unwired as a kit. In either case, wiring work
must only be carried out by qualified personnel.

12 © Festo Didactic GmbH & Co. KG

 Introduction

 Do not pour water over any electrical components. If water is inadvertently poured over electrical
components, switch supply power off immediately. The entire system must be inspected for possible
damage by a teacher or trainer in this case.
 Avoid overloading the digital outputs with excessive current. Maximum current consumption of the
actuators used must be determined before they are connected.

Pneumatics
 Set system pressure to a value between 3 and 6 bar to operate the 2-way ball valve with a pneumatic
semi-rotary actuator. Do not exceed the maximum permissible pressure of 800 kPa (8 bar).
 Do not activate compressed air until all of the tubing connections have been completed and secured.
 Do not disconnect tubing while under pressure.

Mechanical
 Mount all of the components onto the profile plate.
 Make sure that piping and screw connections are carefully secured.

Process engineering
 Always fill the lower tank in the voltage-free state!
 Switch the 24 V DC supply power off and disconnect the power supply unit from the power supply (230
V DC).
 Use potable tap water (recommended), which ensures long-term, maintenance-free operation of the system.
 The maximum permissible operating temperature of +65° C for the tank must not be exceeded.
 The maximum permissible operating pressure of 0.5 bar for the liquid in the tubing may not be exceeded.
 The pump must not be allowed to run dry. The pump must not be used with seawater, contaminated
liquids or viscous media.
 Empty the liquid from the system by opening the drain valve after completing the experiments or before
changing the piping layout.
 Inspect the liquid and replace it at least once a week if contaminated.
 Clean the system as required, but in any case at least once a week. Do not use aggressive cleaning
materials or scouring agents.
 The liquid ages if the system is left at a standstill for a lengthy period of time. Always empty the tanks
and the piping before leaving the system at a standstill for a long period of time.
 No liquids must be allowed to remain in the system for long periods of time, because this may result in
the growth of bacteria such as the so-called legionellae.

© Festo Didactic GmbH & Co. KG 13

Introduction

Technical data, system

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

Power supply for the station 24 V DC / 4.5 A

Profile plate 350 x 200 mm

Station height: with one tank 670 mm

with two tanks 1090 mm

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

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

Clean water tank Max. 3 litres

Flexible piping system DN15 ( 15 mm)

Transport
The EduKit PA project kit is shipped in a Systainer.
The freight forwarder and Festo Didactic must be notified without delay of any damage that occurred in
transit.

Unpacking
Carefully remove the filler material from the Systainer when unpacking the project kit. When unpacking the
project kit, make sure that none of the parts are damaged.
Examine the station for possible damage after unpacking. The freight forwarder and Festo Didactic must be
notified of any damage without delay.

Scope of delivery
Check delivered items against the packing slip and your purchase order. Festo Didactic must be notified of
any deviations without delay.

Visual inspection
Each time the system is started up, it must first be inspected visually.
Perform the following inspections before starting the EduKit PA project kit:
 Inspect electrical connections and wiring.
 Check piping, pipe connectors and pneumatic components, including tubing for correct fitting, leak-
proof sealing and condition.
 Check mechanical and pneumatic components for visible defects (cracks, loose connections etc.).

Eliminate any damages discovered during inspection before starting the station!

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

14 © Festo Didactic GmbH & Co. KG

 Introduction

Maintenance
The EduKit PA project kit is largely maintenance free. The following steps should be carried out at regular
intervals:
 Clean the entire project kit with a soft, lint-free cloth and check components for freedom of movement.
 Inspect liquid for contamination! The liquid may age if the project kit is left unused for any length of
time.
 The system should be drained completely if it is not used for a long period of time.

Updates
Current information on and supplements to the technical documentation for the EduKit PA project kit are
available on the Internet at www.festo-didactic.de/Service/MPS.

© Festo Didactic GmbH & Co. KG 15

Introduction

16 © Festo Didactic GmbH & Co. KG

3. Installation

3.1 Work safety

Information
Work instructions specify in detail how certain steps have to be carried out. Work instructions are tied to a
specific process, a product or a workstation. They form the basis for ensuring that quality standards are met
when the company’s employees carry out their respective tasks. Initial basic instruction on safety in the
workplace and how each person should comply must be completed before specific work instructions are
handed out.

Observe the safety precautions in the introduction!

Safety instructions

Mr./Ms.

Department

Job

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

Subject of instruction Date Instructed person Supervisor (signature)

(signature)

1. General instructions at the fill-level system

2. Instructions on handling liquids

3. Instructions for electrical components

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

appropriately trained personnel.

5. General introduction to: Workshop use

Goods in/out
Working at a PC
Internet and e-mail
Telephone system

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

© Festo Didactic GmbH & Co. KG A-43

3. Installation

3.2 Preassembly, mechanical

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

Task

– Complete the mechanical preassembly of the components of the fill-level system first. Supplement the
assembly plan you created in the chapter on “Planning” by assigning assembly procedures to
components. Use the technical drawings of the components as an assembly guideline. Engineering
drawings of the individual components are included on CD-ROM.
– Write down the assembly times in the assembly plan prepared earlier and modify it if necessary if you
use different steps or discover better alternatives.

3.3 Pre-wiring, electrical

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

Task

– First of all, the electrical components are pre-wired. Proceed in accordance with the layout you have
already created. Follow the circuit diagram with regard to wiring. Then attach the electrical components
to the H-rail.

A-44 © Festo Didactic GmbH & Co. KG

 3. Installation

– Write down the assembly times and modify the assembly plan if necessary if you use different steps or
discover better alternatives. Make a note of any changes to the assembly plan.

3.4 Final assembly with component labelling

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

Task

– During final assembly, screw or clamp all the mechanical and electrical components to the profile plate
and the rectangular profiles and connect the electrical components to each other (see CD-ROM).
– Supplement the components list with the component designations in accordance with the PI flow
diagram and the electrical circuit diagram. Write the designations of the components onto the adhesive
labels and attach them to the respective system components.

© Festo Didactic GmbH & Co. KG A-45

3. Installation

Item no. Graphical symbol Meaning of the graphical symbol Identification

1 P101

2 Measuring point for pressure PI103

measurement with display (component:
pressure gauge)

3 FI
101

7 Tank, container (2) B101, B102

Component list per PI flow diagram

Item no. Graphical symbol Meaning of the graphical symbol Identification

10 Indicator light, start

11 S1
S1

12 Electrical pushbutton, start S2

13 S3
S3

14 Relay

Components list based on electrical circuit diagram

A-46 © Festo Didactic GmbH & Co. KG

1. Manual measurement

1.1 Project task: bath recirculation

1.1.1 Task description

Information
Typical recirculating processes are used in all baths where liquids have to be filtered. For example, leisure
time applications include swimming pools and technical applications include acid baths and galvanising
plants. As the filter becomes more and more contaminated, resistance in the piping system increases
upstream of the filter in proportion to the degree of contamination. When a specified pressure is exceeded,
the filter must be cleaned or replaced. The relationship between resistance (degree of valve opening) and
pressure is determined by experimentation.

Task

– Modification in accordance with the PI flow diagram: modify the basic setup with two tanks so that the
experiments for manual measurement can be done using a single tank. Stopcock V103 represents the filter
for the purpose of the experiment. Filter permeability is simulated by opening and closing the valve.

V103 V102

FI
101

PI B101
103

P101
V105

© Festo Didactic GmbH & Co. KG B-3

1. Manual measurement

1.1.2 Setting up the system, inspection

Work step Done

Modify the piping layout in accordance with the photograph. Remove the piping to the upper tank and insert
blanking plugs into each of the push-in T-connectors.

Close stopcock V105.

Check to make sure that all piping connections are correct.

Check the piping connections to the impeller pump.

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

Fill tank B101 with 3 litres of water.

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

Test execution:
Stopcocks V103 and V102 are fully open and V105 is fully closed. The control switch is turned to the ON
position and the pump delivers water. Stopcock V103 is closed successively in the test setup.

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

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

B-4 © Festo Didactic GmbH & Co. KG

 1. Manual measurement

1.1.3 Experiment: mechanical pressure measurement

Fill the tank and then start the pump. Stopcock V103 is open at first and is gradually closed. Stopcock V103
represents the filter for the purpose of experimentation. Filter permeability is simulated by opening and
closing the valve.
– Read pump pressure from the pressure gauge.
– Observe the volumetric flow rate at the sight glass in the flow meter.

Resistance (degree of valve opening) and pressure

Degree of valve opening as pe [bar] Q [l/min.]

percentage, V 103

Open 0.18

80% 0.32

60% 0.3

40% 0.26

20% 0.22

Closed 0.32

© Festo Didactic GmbH & Co. KG B-5

1. Manual measurement

1.1.4 Evaluation and findings

Task

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

0,35

0,3

0,25
Pressure in bar

0,2

0,15

0,1

0,05

0
100 80 60 40 20 0
Degree of valve opening in %
Pressure

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

_________________________________________________________________________________________

_________________________________________________________________________________________

_________________________________________________________________________________________

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

_________________________________________________________________________________________

_________________________________________________________________________________________

– Explain how an impeller pump works.

_________________________________________________________________________________________

_________________________________________________________________________________________

_________________________________________________________________________________________

B-6 © Festo Didactic GmbH & Co. KG

 1. Manual measurement

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

_________________________________________________________________________________________

_________________________________________________________________________________________

_________________________________________________________________________________________

– Which types of pumps can be used in the field of process technology? Use information from various
manufacturers in order to research your answer. Create a table with typical characteristics, as well as
technical data and the range of applications, for a given type of pump.

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

© Festo Didactic GmbH & Co. KG B-7

1. Manual measurement

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

B-8 © Festo Didactic GmbH & Co. KG

 1. Manual measurement

1.2 Project task: mixing system

1.2.1 Task description

Information
The ingredients fed to a mixing system are usually required in the defined quantity. Mixing systems of this
sort are used, for example, to mix cement. A corresponding amount of water must be fed to the cement
mixer in order to produce a specified concrete mix. The quantity is time-controlled. A prerequisite is that a
constant volumetric flow rate must be maintained, e.g. 60 litres per hour.

The relationships between resistance (degree of stopcock opening), the delivered amount of water and the
required amount of time can be determined by means of an experiment. Run the experiment using the
existing test setup with one tank.

© Festo Didactic GmbH & Co. KG B-9

1. Manual measurement

1.2.2 Experiment: flow measurement

The relationships between resistance (degree of stopcock opening) and volumetric flow rate, as well as the
amount of water delivered within a specific period of time will be examined. In doing so, we’ll look into the
question of how long it takes to pump 2 litres of water into the upper tank with various degrees of opening
at stopcock V103.

Task

– Read the volumetric flow rate at the sight glass in the flow meter.
– Set volumetric flow rate to the required flow rate.
– Fill the upper tank.
– Measure the time it takes for the water level to rise from the 0.5 to the 2.5 litre mark.
– Enter measured time in the table.

Q [l/hr.] Time [s]

400

300

200

100

60

40

Volumetric flow rate per unit of time

B-10 © Festo Didactic GmbH & Co. KG

 1. Manual measurement

1.2.3 Evaluation and findings

Task

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

450

400
Volumetric flow rate in l/hr.

350

300

250

200

150

100

50

0
0 50 100 150 200
Time in s
Volumetric flow rate

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

_________________________________________________________________________________________

_________________________________________________________________________________________

_________________________________________________________________________________________

_________________________________________________________________________________________

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

_________________________________________________________________________________________

_________________________________________________________________________________________

_________________________________________________________________________________________

_________________________________________________________________________________________

© Festo Didactic GmbH & Co. KG B-11

1. Manual measurement

– It takes 0.033 hours to fill the tank to the 2 litre mark. Calculate the volumetric flow rate for any desired
setting for stopcock V101 with the help of the measured time value. Check the selected volumetric flow
rate against the results of your calculation.

_________________________________________________________________________________________

_________________________________________________________________________________________

_________________________________________________________________________________________

_________________________________________________________________________________________

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 4. Automated closed-loop control

4.2 Project task: controlling the fill level using a continuous controller

4.2.1 Task description

If no system deviation is permissible within the control circuit, continuous controllers must be used.
Continuous controllers are characterised by, for example, an analogue manipulated variable in the event
that the sensor has generated an analogue signal. Depending on the control function, the manipulated
variable is calculated by means of various mathematical formulas.

Schematic diagram of a control circuit with a continuous controller

A fill-level system with open outlet (PT1 performance), for example, is used within the control circuit.

Controller Process
w (0...1) Manipulated
Control function Signal amplifier Controlled system Sensor Actual value
Setpoint variable
Y = ... y (0...1) x (0...1)

The following controller functions (selection) could be used:

Controller Graphic symbol Function

P controller y = kp • e

kp = adjustable amplification factor

e = system deviation w - x

I controller y = esum • TA/Ti

Adjustable integral time (Ti)

esum = sum of system deviation e

System deviation e is added up during each cycle.

PI controller Y = kp • ( e + esum • TA/Tn)

Adjust kp and reset time (Tn)

TA = sampling time, programme cycle time

PID controller Y = kp • (e+ esum • TA/Tn+ (e-e_alt) • Tv/TA)

Adjust derivative time (Tv),

e_alt = system deviation from the previous cycle

Note
The pump must be operated in the analogue mode for continuous control. Control voltage from the
EasyPort to the motor control is between 0 and 10 V. Changeover relay K1 must be set with A2 = 1 to this
end.

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4. Automated closed-loop control

4.2.2 Experiment: controlling the fill level with a continuous controller

In this experiment the fill level will be controlled with a continuous controller. In the example included in the
chapter entitled “Manual control of fill level”, the fill level was kept constant by varying the power supply
unit’s output voltage. The manipulated value will now be read out by the software. The experiment should
be carried out with four different controllers.

Various settings must be entered in order to test the performance of the control circuit. In order to be able to
draw any conclusions, it’s always advisable to change only one parameter at a time and then conduct the
experiment. The settings included in the following table are suggestions.

– Start the software and open the “Continuous control” menu.

– Check the software settings: set changeover relay A2 = 1 and specify the setpoint.
– Carry out the experiment with P, I and PI controllers.
– Add your observations to the table.

Depending on the software revision level, the setpoints may also have to be entered in a sub-window.

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 4. Automated closed-loop control

4.2.3 Experiment: controlling the fill level using a proportional controller

Note
Empty B102 before each start-up!

– Select each of the values listed below and carry out the experiment.
– Document your observations.

Settings Observations

No. Setpoint w, Setpoint w Amplification Disturbance

physical (standardised) kp variable z, hand
valve V103

1 1 litre 0.3 0.5 10% open

2 1 litre 0.3 2 10% open

3 1 litre 0.3 10 10% open

4 1 litre 0.3 5 0% open

5 1 litre 0.3 5 20% open

6 2 litres 0.2 5 100% open

Sample solution for fill-level control with a P controller

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4. Automated closed-loop control

Task

– Which characteristics is the control circuit (P controller, PT1 system) displaying?

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4.2.4 Experiment: controlling the fill level using an integral controller

Note
Empty B102 before each start-up.

Software setup
The manipulated value of the I controller is calculated as follows:

Y = total of all system deviation (e:sum) x sampling time (TA)/integral action time (Ti)

This formula makes it clear that Y is quickly changed by the controller when Ti is small, and Y is changed
slowly, i.e. the controller is sluggish, when Ti is large. Make sure that Ti does not drop to 0, otherwise Y
would be undefined in this case. Switch the software to “I controller”.
The physical setpoint depends on the size of the tank and whether the unit of measure of the fill level will be
in litres or in mm.

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 4. Automated closed-loop control

– Select each of the values listed below and carry out the experiment.
– Document your observations.

Settings Observations

No. Setpoint w, Setpoint w Integral Disturbance

physical (standardised) action time variable z, hand
(Ti) valve V103

1 – 0.3 1 10% open

2 – 0.3 0.5 10% open

3 – 0.3 0.1 10% open

Note
It is possible that no stabilisation occurs in an actual system and that continuous oscillation takes place.

Sample solution for controlling the fill-level with an I controller

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4. Automated closed-loop control

Task

– What is the effect of integral time?

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– What can we say about system deviation?

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4.2.5 Experiment: controlling the fill level using a proportional-integral controller (parallel P and I
components)

In order to take advantage of the positive characteristics of both the P and the I controller, the two will be
combined. This can be done in two different ways:

kp = 1

kp

The controllers are connected in parallel in the combination shown on the left and in series in the combination
on the right. In actual industrial practice, the combination shown on the right is used in accordance with DIN
19226.

Note
Empty B102 before each start-up.

– Select each of the values listed below for the PI (DIN) controller and carry out the experiment.
– Document your observations.

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 4. Automated closed-loop control

Settings Observations

No. Setpoint w Amplification Reset time Tn Disturbance

(standardised) kp variable z, hand
valve V103

1 0.5 litres 00.5 1 sec. 10% open

2 0.5 litres 1 1 sec. 10% open

3 0.5 litres 3 1 sec. 10% open

4 0.5 litres 3 0.1 sec. 10% open

Sample solution for controlling the fill-level with a PI controller

Task

– What can we say about reset time Tn?

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– What can we say about system deviation?

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© Festo Didactic GmbH & Co. KG C-55