PDF Planta Control

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Control Technology – a classic discipline of technical training

Advancing automation is increasingly conferring the monitoring and control of

technical processes and production techniques to autonomous control systems.

Mechanical controls are thus relieving humans from performing monotonous control

and operating tasks. However technical systems often require a level of accuracy,

speed and reliability that humans would not be able to fulfill. Our control technology

training system employs an training panel system for basic and advanced courses.

The multimedia training system, based on COM3LAB, is equally well suited to

student self-help practice and experiment demonstrations with a PC beamer.

Basic Course

Basic courses in control technology employ real technical controlled systems. These

produce non-electrical controlled variables (fill level, temperature, flow rate, angle of

heel, etc.) and therefore require sensors to convert the given quantities into electrical

signals. Since here explicit results take on foreground importance, these experiments

are particularly well suited for a basic introduction to this thematic.

Advanced Course

Advanced courses in control technology employ pure electronic devices as controlled

systems. Sensors are no longer necessary here because only electrical signals occur

in the entire control circuit. Since electrical signals are easily managed, these

experiments stand out as a consequence of their convincingly quantifiable results.

The results assessed here also stand up to critical interpretation.

Symbols:

Experiment literature included

Battery required

Software included

COM3LAB compatible

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Temperature Control

T 8.2.1.1

T 8.2.1.1

Training Objectives

➔

Temperature control with two-point controller

➔

Hysterisis of two-point controller

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Temperature Control

T 8.2.1.1

T 8.2.1.1

Some like it hot

Instead of the oven model 734 38 from T 8.1.3 Process Instrumentation

Tech-nology, the thermally quicker Temperature Controlled System 734 12 is used

here. This increases the dynamics of control and shortens measurement

time.

EQUIPMENT LIST T8.2.1.1

Temperature Control

QUANTITY CAT. NO. DESCRIPTION

1 734 01 Two Position Controller 1 734 02 Reference Variable Generator 1 734 12 Temperature Controlled System 2 734 13 Power Amplifier

1 524 016 Profi-CASSY

1 734 48 WinFACT 6-COM3LAB / CASSY-Edition

1 568 222 Book: Fundamentals of Automatic Control Technology II, Vol. 2

Foundries must maintain exacting, prescribed, temperature profiles for the molten mass.

Basic Course: Technical Systems

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Liquid Level Control

Flow Rate Control

T 8.2.1.2

T 8.2.1.3

Liquid level control with DDC controller under CASSYLab.

Training Objectives

➔

Control of fill level height on single tank model

➔

Control of fill level height on dual tank model

➔

Control of liquid flow rate

➔

Disturbance behavior in the Liquid Controlled System

T 8.2.1.2_{T 8.2.1.3}

T 8.2.1.2 T 8.2.1.3

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Liquid Level Control

Flow Rate Control

T 8.2.1.2

T 8.2.1.3

Basic experiment: Liquid level control on a single tank model

1 734 262 Liquid Controlled System 1 734 02 Reference Variable Generator 1 734 81 Differential Pressure Transducer 1 734 876 Immersion Tube

1 568 1012 Book: Experiments with the Liquid Controlled System T 8.1/8.2

Supplementary experiment: Liquid level control on a dual tank

model

The basic experiment can be extended for the dual tank model. The probes listed below can also be used in the basic experiment 1 734 264 Additional reservoir

1 727 68 C/F-, L/F- and F/U-Converter 1 734 861 Capacitive Bar-Type Probe 1 734 881 Level Switch with Float 1 734 89 Capacitive Level Switch 1 734 901 Gravimetric Level Meter

Flow Rate Control

1 734 262 Liquid Controlled System 1 734 02 Reference Variable Generator 1 524 016 Profi-CASSY

Two in a boat

Liquid level and flow can both be measured with one instrument. The

illus-trated experiment uses the same liquid level measurement as T 8.1.3.2 to

maintain a pre-selected fill level height with a closed loop controlled system.

The experiment is quite clear and demonstrates, in an instructional manner,

the interrelationship between reference value and actual value in feedback

loops.

Basic Course: Technical Systems

T 8.2.1.2 T 8.2.1.3

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Gas Flow Control

T 8.2.1.4

Flow Control with blower and windmill type anemometer.

Training Objectives

➔

Control of a technical system with a moderate time constant

➔

Evaluation of the step response

➔

Determination of system time constants

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They don‘t all have the same time

A system‘s responsiveness to state changes is determined by its time

con-stants. Technical systems can exhibit significantly different time constants:



temperature : very slow



flow : slow



rotary speed : moderately fast



brightness : very fast

The control techniques investigated here are used for process control and in

air conditioning systems.

Gas Flow Control

T 8.2.1.4

Gas Flow Control

1 666 630 Blower 1 666 631 Venturi Tube

1 666 632 Windmill Type Anemometer 1 524 016 Profi-CASSY

1 568 342 Book: Flow-Through Measurement of Gases T 8.1.3.4

T 8.2.1.4

Basic Course: Technical Systems

While wind force and direction are constantly being measured in wind power generators, the availability of wind can’t be controlled by man.

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Brightness Control

Speed Control

T 8.2.1.5

T 8.2.1.6

T 8.2.1.5 Training Objectives

➔

Brightness Control with PI controller

➔

Dynamic properties of fast closed loop control

T 8.2.1.5 T 8.2.1.6

Small but super! Light controlled system and mini-machine system. The motor-generator set consists of two coupled DC machines and an

optical tacho-generator.

T 8.2.1.6 Training Objectives

➔

Speed control of a motor-generator set with PID controller

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Brightness Control

Speed Control

Brightness Control

1 578 51 Si Diode 1N 4007

1 734 02 Reference Variable Generator 1 734061 PID Controller

1 734 13 Power Amplifier

1 734 16 Manual/Automatic Switch 1 734 31 Light Control System 1 524 016 Profi-CASSY

T 8.2.1.5

T 8.2.1.6

T 8.2.1.5 T 8.2.1.6

Light-Velocity

Brightness control is a practical example for the control of „fast“ systems.

This finds application in large lighting systems in sports arenas, halls, etc.

Speed control is another daily life application. In the experiment the

con-trolled system (= motor) provides the non-electric concon-trolled variable

„speed“. The generator coupled to the motor acts as a sensor that converts

the motor‘s rotary speed into an electrical voltage signal.

Speed Control

3 505 23 Lamp 24 V / 5 W

1 734 02 Reference Variable Generator 1 734 061 PID Controller

1 734 11 Motor-Generator Set, 24V 1 734 13 Power Amplifier

2 734 19 Gain and Offset Adjust 1 734 39 Load Switch

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Listing controllers ensure a balanced course tracking for big transportation vessels.

Listing Control

T 8.2.1.7

Training Objectives

➔

Putting listing control into service

➔

Control parameter settings for stable stationary operation

➔

Creating oscillating instabilities

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Listing Control

T 8.2.1.7

T 8.2.1.7

Ship shape in bad shape

The list (heeling over) of a container ship or ferry changes as it is loaded.

Difficulties can also arise, for example, in keeping the pitch of railroad tracks

aligned while moving railroad cars onto a ferry. The appropriate filling of

ballast tanks can help to compensate for such undesirable ship list and

pitch-angles.

Profi-CASSY and its CASSYLab software combine to serve as a convenient controller. Controller parameters, as well as the controlled, manipulated and reference quantities are visible at a glance.

Basic Course: Technical Systems

Listing Control

1 734 300 Listing Controlled System 1 524 016 Profi-CASSY

1 734 48 WinFACT 6-COM3LAB / CASSY-Edition 1 510 48 Pair of Magnets

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Air conditioning system with fuzzy controller.

The controlled system can be electrically heated with a halogen lamp and cooled by a fan.

Fuzzy Control

T 8.2.2

Training Objectives

➔

Implementation of an electronic gas pedal (drive by wire)

➔

Control of an air conditioning system with fuzzy algorithm

➔

Speed control of vehicles with differing loads

➔

List control with fuzzy algorithm

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Fuzzy Control

T 8.2.2

Of approximate values and

membership functions

Fuzzy describes an approach to the control of technical systems which

avo-ids sophisticated mathematical modeling. The control strategy is defined in

terms of conditional language. Fuzzy control is particularly well suited for

systems with multiple controlled variables and is used frequently today in

many common appliances, from washing machines to cameras.

EQUIPMENT LIST T8.2.2

Fuzzy Control

1 734 10 Servo Set point Generator 1 734 11 Motor-Generator Set, 24V 1 734 12 Temperature Controlled System 2 734 13 Power Amplifier

1 734 14 DC-Servo 1 734 56 Tensile Test Bar

1 734 300 Listing Controlled System 1 524 016 Profi-CASSY

1 734 4722 WinFACT 6-Student License Type B 1 510 48 Pair of Magnets

T 8.2.2

Fuzzy techniques can even be found in automotive engineering. The „drive by wire“ technology transmits the driver‘s wish to change speed to a fuzzy controller.

Basic Course

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Continuous Control

T 8.2.3

Training Objectives

➔

Transient functions from P-controller and I-controlled systems

➔

Feedbacks in transfer elements

➔

Output quantities in an open loop control chain

➔

Simulation of a pneumatic pressure closed loop control

➔

Pneumatic pressure closed loop control

➔

Step-responses of PT1 and PT2 elements

➔

Characteristic of a temperature closed loop control

➔

Dead time element

➔

Transient function of various controls:

PI-control, PIP-control with 1st order delay,

PIDP-control with 1st order delay

T 8.2.3

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A cybernetic base model

The set-up photo shows a typical course T 8.2.3 experiment configuration.

The electronic control loop is made of discrete components. This type of

structure is ideal for the simulation of technical control loops. The advantage

to this approach is its simple mastery of electrical quantities in comparison

to (somewhat more complex) physical process quantities.

Continuous Control

1 734 02 Reference Variable Generator 2 734 03 P Controller

1 734 04 Integral-Action Element 1 734 05 Derivative-Action Element 1 734 07 Summing Point, 2 Inputs 1 734 08 Summing Point, 5 Inputs 1 734 089 Dead Time Element 2 734 09 Simulated Controlled System 1 734 12 Temperature Controlled System 1 734 13 Power Amplifier

1 734 40 Test Function Generator 1 524 016 Profi-CASSY

Continuous Control

T 8.2.3

T 8.2.3

Advanced Course

Control loop odels: 1 controller 2 actuator

3 controlled system 4 sensor

The upper block diagram shows a closed loop control in general form. The controlled variable X and the reference variable W are different physical quantities and must be transformed for compatibility to one another by way of sensor technology. The actuator provides the control loop with the necessary power. The lower block diagram illustrates a simplified closed loop control. The actuator is integrated into the controller or the controlled system. Here the controlled variable and the reference variable are of the same physical nature, this makes sensors unnecessary.

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Discontinuous Control

T 8.2.4

T 8.2.4

Advanced Course

Training Objectives

➔

Temperature control with a two point controller

➔

Discontinuous control with feedback

The steam iron is a classic example of an application with a two-point controller.

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Discontinuous Control

1 734 01 Two Position Controller 1 734 02 Reference Variable Generator 1 734 08 Summing Point, 5 Inputs 1 734 09 Simulated Controlled System 1 734 095 Second Order Transfer Element 1 734 12 Temperature Controlled System 1 734 13 Power Amplifier

1 568 232 Book: Fundamentals of Automatic Control Technology II, Vol. 1 1 568 222 Book: Fundamentals of Automatic Control Technology II, Vol. 2

Discontinuous Control

T 8.2.4

T 8.2.4

Discrete steps

The temperature of a steam iron will rarely take on directly the desired

refe-rence value. In contrast to continuous control systems, the controlled system

(heater) here can only be turned on or off. There are no intermediate values.

There isn‘t even an active cooling mechanism available.

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Controlled System Classes

T 8.2.5

T 8.2.5

Experimental set-up for computer-aided recording of step responses.

Training Objectives

➔

Simulation of fill level control

➔

Investigation of reference behavior

➔

Investigation of oscillation behavior

➔

Control of a controlled system with start-up time and dead time by a

PID-controller

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Controlled system Classes

1 734 02 Reference Variable Generator 1 734 03 P Controller

1 734 04 Integral-Action Element 1 734 063 PID Controller, 10 Turn 1 734 07 Summing Point, 2 Inputs 1 734 08 Summing Point, 5 Inputs 1 734 089 Dead Time Element 1 734 09 Simulated Controlled System 1 524 016 Profi-CASSY

Class reunions

Controlled systems which are important from a technical point of view will

be systematically classified here according to their recorded time behavior

characteristics. Experiments with 10-turn PID-controllers achieve astonishing

quantitative correlation between theory and measurements. For anyone who

places value on theoretically quantifiable control techniques, this controller

is a recommendable alternative to the standard design (734 061).

Controlled System Classes

T 8.2.5

T 8.2.5

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Recording the locus diagram on a system with dead time.

Electronic Systems

T 8.2.6

T 8.2.6

Training Objectives

➔

Step response

➔

Frequency response

➔

Systematic of controlled systems

➔

Systematic of controllers

➔

Digital controllers

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T 8.2.6

Electronic Systems

Idea and reality

Electrical control systems that replace their physical counterparts while

maintaining the same system behavior are investigated here.



pressure closed loop control



temperature closed loop control

T 8.2.6

Electronic Systems

2 734 03 P Controller

1 734 04 Integral-Action Element 1 734 41 Sample and Hold Element 1 734 061 PID Controller

2 734 07 Summing Point, 2 Inputs 1 734 08 Summing Point, 5 Inputs 1 734 089 Dead Time Element 2 734 09 Simulated Controlled System 1 734 095 Second Order Transfer Element 1 524 016 Profi-CASSY

Control and evaluation with the PC. In DDC (Direct Digital Control) mode, the Profi-CASSY acts as the interface between the control loop and the PC. Together with CASSY Lab or WinFACT software, the computer can take over various tasks:

 to provide a freely-configurable digital controller

 taking over of recording tasks as an XY/Yt recorder or step response plotter This also allows experiments

to be performed in the time and frequency domain, e.g. the recording of step responses or the presentation of locus diagrams.

Advanced Course

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Stability & Optimization

T 8.2.7

Training Objectives

➔

Simulation of electric motor speed control

➔

Stability testing a 3rd order control system

➔

Stability testing a simulated gas flow controller

➔

Controller settings for a controlled system with dead time

➔

Nyquist evaluation of a control system

➔

Nyquist evaluation of an oscillating closed loop control

➔

Experimental optimization by means of ISE criteria

➔

Optimizing according to Ziegler / Nichols

➔

Optimizing according to Chien / Hrones / Reswick

➔

Fundamental stability investigations

➔

Higher order systems

➔

Stability test on an open loop control

➔

Integral criteria for system optimization

➔

Controller optimization

T 8.2.7

Locus diagrams of an open loop control system for stability evaluation per Nyquist.

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Stability & Optimization

1 734 04 Integral-Action Element 1 734 063 PID Controller, 10 Turn 1 734 08 Summing Point, 5 Inputs 1 734 089 Dead Time Element 2 734 09 Simulated Controlled System 1 734 095 Second Order Transfer Element 1 734 19 Gain and Offset Adjust 1 524 016 Profi-CASSY

1 734 48 WinFACT 6-COM3LAB / CASSY-Edition 1 727 71 Function Module

Stability & Optimization

T 8.2.7

On the swing

Control loops are feedback coupled systems. As such, they tend to oscillate

under certain conditions. This effect is generally undesirable and demands all

of the engineer‘s talents to create a design that is adequate for its dynamic

behavior yet does not lead to parasitic oscillations that could endanger the

system or the process.

T 8.2.7

Advanced Course

Some have their own intuitive notions about stability and process optimization. For the technician, this subject is a more somber matter but certainly no less interesting.

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COM3LAB Course Control Technology I

COM3LAB Course Control Technology II

70082

70083

Training Objectives 70082

➔

Everyday open and closed loop control

➔

Analysis of controlled systems

➔

Plants with/without compensation

➔

Higher order systems

➔

PID and PI control

➔

Digital control

➔

Performance criteria

➔

PID controller settings

➔

Temperature control

➔

Rotary speed control

➔

Light Control

➔

Control with discontinuous controllers

➔

Fault simulation

Training Objectives 70083

➔

Control system stability

➔

Controller design per Ziegler / Nichols

➔

Systems with deadtime

➔

Reference variable limitations

➔

Cascade control

➔

Introduction to frequency response

➔

Frequency responses of individual basic

elements

➔

Frequency response of combined elements

➔

Controller design in the frequency domain

➔

Fuzzy control

➔

Adaptive Control

COM3LAB: master unit and course board are the only training materials required to conduct the computer-aided experiments.

70082 70083

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Measuring in the virtual laboratory

COM3LAB frees you of the inconvenience associated with obsolete

measu-ring instruments. PC and master unit are all that is required – and then the

course‘s software unfolds on any pupil‘s desk into a richly equipped

instru-ment laboratory with the following instruinstru-ments:



static characteristic plotter



step response plotter (for analog control)



DDC plotter (for sampling control)



controller design computer for calculating optimal controller parameters

from specified system parameters



two multimeters



function generator (synthesizer)



oscilloscope



frequency analyzer



logic analyzer

COM3LAB Course Control Technology I

COM3LAB Course Control Technology II

70082

70083

EQUIPMENT LIST

COM3LAB Control Technology I/II

1 700 82 COM3LAB Course: Control Technology I 1 700 00 COM3LAB Master Unit

recommended:

1 700 83 COM3LAB Course: Control Technology II

The COM3LAB Control Technology II course is a supplementary course to 700 82. It uses the same experiment board and can be released by a dongle on course I.

The control process is recorded on the DDC plotter versus the time axis. The reference variable is red, the manipulated variable is green and the controlled variable is blue. The example shows the rotary speed control of a fan motor as affected by a PID controller for various reference variables.

Multimedia

70082 70083

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