Electropeneumatics

8/20/2019 Electropeneumatics

1/164

NikiniNikiniNikiniNikini

ELECTROPNEUMATICSELECTROPNEUMATICS

© Nikini Automation Systems (Pvt) LtdElectropneumatics Tuesday, September 21, 2010

NikiniNikiniNikiniNikini Automation Systems (Pvt.) Ltd.


2/164


Overview

1. Introduction to Electro-pneumatics systems2. Switches and Sensors

3. Reco nizin and drawin of electrical s mbols


4. Electrical Signal processing

5. Electro-pneumatic actuators

6. Solving simple control problems using electro-pneumatics

7. Solving control problems using multi actuator

electro-pneumatic systems


3/164


Timing of the workshop

• Session 1 09.00 a.m.• Break 10.15 a.m.

• Session 2 10.30 a.m.


• Lunch 12.15 p.m.

• Session 3 01.15 p.m.

• Break 03.00 p.m.• Session 4 03.15 p.m.

• Conclusion 04.00 p.m.


4/164


• Electropneumatics is controlling of pneumaticsystems using electrical control systems.

• Hybrid system using of both pneumatic and

1.Introduction


electrical energies.• Used in many areas of industrial automation.

– Production

– Assembly and packaging systems

– Etc.


5/164


Control Engineering

• Pneumatic drives can only do work usefully iftheir motions are precise and carried out at the

right time and in the right sequence.


• Coordinating the sequence of motion is the task ofthe controller.

• Control engineering deals with the design and

structure of controllers.


6/164


• Pneumatic control system pneumatic components are used.– Various types of valves

– Sequencers


– air barriers• Electro-pneumatic control system electrical components

are used.

– electrical input buttons

– proximity switches

– relays

– programmable logic controller


7/164


Power Components

Cylinder

Swivel cylinder

Pneumatic motor

Optical display

Final control element

Directional control

valves

Command

execution

Signal

Output

P n e u

m a t i c p o w e r

s e c t i o n


Processing elementsShuttle valves

Two-pressure valves

Pressure control valves

Sequences

Input elementsDirectional control valves

(Mechanically operated/

Manually operated)

Air barriers

Signal

Processing

Signal Input

Signal Flow Pneumatic components

P n e u m a t i c c o n t r o l s e c t i o n


8/164


9/164

NikiniNikiniNikiniNikiniElectrical control section


Electrical directional control valve

Cylinder with proximity switches


10/164


Advantages of electro pneumaticcontrollers

• High reliability:– Fewer moving parts subject to wear

• Lower planning and commissioning effort


– or comp ex contro s.• Lower installation effort

– when modern components such as valve terminals areused.

• Simpler exchange of information between severalcontrollers.


11/164


• Electro-pneumatic controllers have assertedthemselves in modern industrial practice.

• A lication of urel neumatic controls s stems


is limited to a fewer special applications.


12/164


Fundaments of electricaltechnology

• A simple electrical circuit consists of avoltage source, a load, and connection lines.

•


.

– Current can only flow if the circuit is closed.

• Two types of current

– Direct current– Alternating current


13/164


Direct current Alternating current


C u r r e n t

Time (t) Time (t) C

u r r e n t


14/164


DC circuit


V=12V

S

H

4


15/164


Power supply unit



16/164


• The transformer reduces the operating voltage.– 230 V to 24 V

• The rectifier converts the AC voltage into DC


vo tage.• The capacitor at the rectifier output smoothes the

voltage.

• The voltage regulator

– To ensure that the electrical voltage remainsconstant regardless of the current flowing.


17/164


2.Switches

• Switches (& Sensors) are the means ofsignal generation in a electrical controlsystem.


• Switches are installed in circuits to apply acurrent to a load or to interrupt the circuit.

• Basic components of the switch are

contacts.• There are many ways to actuate a switch.


18/164


Normally open contact



19/164


Normally closed contact



20/164


Changeover contact



21/164


Normally open push button

Input elements – Switches



22/164


Normally closed push button




23/164


Change over switch




24/164


Input elements – SwitchesPlease refer to the video to get a summarization

of the different kind of switches


Switches NO, NC, CO

and an application example !

Application of switches


25/164


Input elements – SwitchesPlease check the numbers of the contacts of a

normally open and normally closed contact at the

si nal in ut device of Festo.


Are there any differences and if yes which one?


26/164


Identity logic


Indicator light

Electrical connection 0VElectrical connection 24V


27/164


Negation Logic


Indicator light



28/164


AND Logic


Indicator light



29/164


OR Function


Indicator light


us u on ma e


30/164


Mechanical limit switch

1: Reset spring

2: Housing

3: Swing lever

4: Guide pin


5: Leaf spring

6: Contact spring

Normally open

contact

Normally close

contact


31/164


Mechanical limit switch



32/164


Switching Contacts and Types ofActuation: Symbols



33/164


4.Signal Processors: Relays



34/164


• A relay is an electro magnetically actuated switch.• When a voltage is applied to the relay coil, an

electromagnet field results.

Relays


• s causes t e armature to e attracte to t e cocore.

• The armature actuates the relay contacts, eitherclosing or opening them, depending on the design.

• A return spring returns the armature to its initialposition when the current to the coil is interrupted.


35/164


Return spring

CoverSymbol

A1

1214

2224

Armature

Processing elements – Relays -

Repetition


Coil

Coil connections

Contacts

Contact connections

A2 11 21


36/164


A1

1214

2224

Symbol


Repetition


A2 11 21

A1 A2 4 2 1


37/164


A1

1214

2224

Symbol


Repetition


A2 11 21

A1 A2 4 2 1


38/164


A1

1214

2224

Symbol


Repetition


A2 11 21

A1 A2 4 2 1


39/164


A1

1214

2224

Symbol


Repetition


A2 11 21

A1 A2 4 2 1


40/164


Relay Contact Configuration



41/164


Charateristics of a Relay

• A Relay has Certain Characteristics– Different voltage levels

– Multiple switching operation


– Different control paths– Used for logic functions and interlocking

– Ease of maintenance


42/164


ExerciseExerciseExerciseExercise

The exercise should be:

is it possible to connect a

solenoid of a valve 1M1 directly

via a proximity sensor 1B1 if the

data are:


P of the valve = 4.5 W at 24 VDC

and

I max over the sensor = 50 mA

Internal resistor of the proximity

sensor is 0

ANSWER:______________


43/164


Solution 1Solution 1Solution 1Solution 1

May be it could help to put

another resistor in front of the

solenoid to reduce the current.

The questions are here:

1. What is the value of the


resistor R1?2. What is the real power over the

solenoid and

is that enough to switch the

valve

R1


44/164


Solution 2Solution 2Solution 2Solution 2

The perfect solution is to connect

any kind of sensors and switches

to a rela first and the


corresponding relay contact to thesolenoid of the valve.


45/164


Contactors

• Contactors operate in the same way as arelay.

•


– Double switching (dual contacts)

– Closed chambers (arc quenching chambers)

• These design features allow contactors toswitch much higher currents than relays.


46/164


Contactors


Niki iNiki iNiki iNiki i


47/164


Function of a solenoidFunction of a solenoidFunction of a solenoidFunction of a solenoid

In electropneumatic controls,

solenoids are primarily used to

control the switchin of valves,

Solenoids


relays or contactors.



48/164


Function of a solenoidA magnetic field is induced when

a current is passed through an

electrical conductor. The stren th


of the magnetic field isproportional to the current.

Magnetic fields attract iron,

nickel and cobalt. The attraction

increases with the strength of themagnetic field.



49/164


Function of a solenoidFunction of a solenoidFunction of a solenoidFunction of a solenoid

Please refer to the video to get some additional

information regarding the phenomena of

electroma netism


Electromagnetis

m principles



50/164


2/2 Way solenoid valve

2/2-Way solenoid valve without pilot control




51/164


Direct/ Pilot solenoid valves

• Disadvantages of direct solenoids:– Higher force required to actuate the armature.

–


– Higher power consumption.

– Heating.



52/164


Solenoid Valves with Pilot Control

• Solenoid valves with pilot control consist of:– An electromagnetically-actuated pilot control valve.

– A pneumatically-actuated main valve.


• Advantages:– Lower force required to actuate the armature.

– Smaller dimensions of the coil head.

– Lower power consumption.

– Less heat generated.



53/164


3/2 Way solenoid valve3/2-Way Single solenoid valve with pilot control




54/164


Pilot operation




55/164


1M1

5/2 Way single solenoid valve


5/2-Way Single solenoid valve with pilot control



56/164


5/2 Way single solenoid valve5/2-Way Single solenoid valve with pilot control and exhaust for pilot




57/164


Control elementsControl elementsControl elementsControl elements –––– Pilot controlled 5/2 way valve single solenoidPilot controlled 5/2 way valve single solenoidPilot controlled 5/2 way valve single solenoidPilot controlled 5/2 way valve single solenoid


2222

(B)(B)(B)(B)

3333

(R)(R)(R)(R)

1111

(P)(P)(P)(P)

5555

(A)(A)(A)(A)

4444

(S)(S)(S)(S)



58/164




2222

(B)(B)(B)(B)

3333

(R)(R)(R)(R)

1111

(P)(P)(P)(P)

5555

(A)(A)(A)(A)

4444

(S)(S)(S)(S)



59/164




2222

(B)(B)(B)(B)

3333

(R)(R)(R)(R)

1111

(P)(P)(P)(P)

5555

(A)(A)(A)(A)

4444

(S)(S)(S)(S)



60/164




2222

(B)(B)(B)(B)

3333

(R)(R)(R)(R)

1111

(P)(P)(P)(P)

5555

(A)(A)(A)(A)

4444

(S)(S)(S)(S)



61/164




2222

(B)(B)(B)(B)

3333

(R)(R)(R)(R)

1111

(P)(P)(P)(P)

5555

(A)(A)(A)(A)

4444

(S)(S)(S)(S)



62/164




2222

(B)(B)(B)(B)

3333

(R)(R)(R)(R)

1111

(P)(P)(P)(P)

5555

(A)(A)(A)(A)

4444

(S)(S)(S)(S)



63/164




2222

(B)(B)(B)(B)

3333

(R)(R)(R)(R)

1111

(P)(P)(P)(P)

5555

(A)(A)(A)(A)

4444

(S)(S)(S)(S)



64/164



2222

(B)(B)(B)(B)

3333

(R)(R)(R)(R)

1111

(P)(P)(P)(P)

5555

(A)(A)(A)(A)

4444

(S)(S)(S)(S)



65/164




66/164

Control elementsControl elementsControl elementsControl elements –––– Solenoid valvesSolenoid valvesSolenoid valvesSolenoid valves

Pilot controlled 5/2 wayvalve double solenoid

1M1 1M2




67/164

5/2 Way double solenoid valve5/2-Way double solenoid valve with pilot control and exhaust for pilot




68/164

Control elements – Solenoid valves -

Summarization


Summarization pilot controlled solenoid valves



69/164

5/3 Way solenoid valve




70/164

Common Solenoid Valves

Valve Type Symbol Applications

Pilot controlled spring

return 2/2-way valve

Shut-off function


Pilot controlled springreturn 3/2-way valve,

normally closed

Single-actingcylinders


return 3/2-wayvalve,normally open

Switching

compressed air

on and off



71/164




return 4/2-way valve

Double-acting linear or

swivel cylinders


Pilot controlled

springreturn 5/2-way

valve


swivel cylinders



72/164



Pilot controlled

springreturn 5/2-way valve


swivel cylinders with


,

exhausted or

pressurized)Pilot

controlled spring return

4/2-way valve

,

special requirements

regarding behavior in

event of power failure.



73/164



Pilot controlled 4/2-way double solenoid

valve

Double-acting linear orswivel cylinder


Pilot controlled 5/2-way double solenoid

valve

Double-acting linear orswivel cylinder



74/164

Switching Symbols for SolenoidCoils and Relays




75/164

Electrical Output Devices




76/164

Electropneumatic Exercises




77/164

Circuit Diagram Conventions


Pneumatic Circuit Electrical Circuit



78/164

Circuit Diagram Structure

• Pneumatic Circuit Diagram

– The arrangement of the components follows the signalflow accordingly from bottom to top.

–


.

– The outward travel motion of cylinders should be fromleft to right.

• Electrical

– The arrangement of the components follows the signal

flow accordingly from top to bottom.– The electrical circuit diagram can be subdivided into a

control part and a power part.



79/164

Circuit Diagram Structure


Control

Section

PowerSection



80/164

Feeding a work pieceIn this application, cans will be

closed with a cover. The

definition of the process is:

The startin osition of the


piston rod of the cylinder is the

rear end position. By pressing

and holding a push button, the

cover shall be pressed onto the

can. After releasing the pushbutton the piston rod of the

cylinder shall move back to the

rear end position.



81/164

Project 1: Information phase –

Principles of circuits

Please refer to the video to get some informationregarding the principles of Electro-Pneumatic

circuit dia rams:


• Pneumatic circuit diagram

• Wiring diagram

Principles of Electro-Pneumatic circuits



82/164

Project 1: Information phaseProject 1: Information phaseProject 1: Information phaseProject 1: Information phase –––– Pneumatic circuitPneumatic circuitPneumatic circuitPneumatic circuit




83/164

Project 1: Information phaseProject 1: Information phaseProject 1: Information phaseProject 1: Information phase –––– Wiring diagramWiring diagramWiring diagramWiring diagram




84/164

Project 1: SolutionProject 1: SolutionProject 1: SolutionProject 1: Solution

Direct Control




85/164

Heavy Work piece feeding


Work piece fed using a double acting cylinder.

The piston rod is extended when an electrical push button is pressed

and returned to initial position when push button is released.

5/2 way single solenoid valve is used to control the cylinder.

The Solenoid should be actuated indirectly.



86/164

Indirect Control


???

???


di C l


87/164

Project 2: SolutionProject 2: SolutionProject 2: SolutionProject 2: Solution

Indirect Control


1V1

+

-


H W k i f di


88/164

Heavy Work piece feeding



The piston rod is extended when an electrical push button (S1) is

pressed and kept extended until another push button (S2) is pressed

to retract the piston rod to initial position.

5/2 way single solenoid valve is used to control the cylinder.


El i l L hi


89/164

Electrical Latching


Electrical lacing circuits are divided in on- and off

dominant. Please refer to the video to see the basic

function


M Ci it D i t R t


90/164

Memory Circuit- Dominant Reset1A

+24V

START K1K1

1 2 3


5

1

3

1Y1

0V

1Y1K1

RESET

2

3


M Ci it D i t S t


91/164

Memory Circuit- Dominant Set1A

+24V

START K1K1

1 2 3


5

1

31Y1

0V

1Y1K1

RESET

2

3

NikiniNikiniNikiniNikiniStroke Dependent Control


92/164

(Automatic Return)



The piston rod is extended when a push button is pressed.

Piston rod returns to initial position when a limit switch at forward

position is switched.

NikiniNikiniNikiniNikiniStroke Dependent Control


93/164

(Automatic Return)1A A2

+24V

START K1K1

1 2 3


4 2

5

1

3

1Y1

0V

1Y1K1

A2

2

3

NikiniNikiniNikiniNikiniHeavy Work piece feeding

C i i


94/164

Continuous operation

1. Piston moves forward when

it reaches 1B1

2. Return to initial position

LS1 LS21 A


automatically when piston

moved to 1B2

3. Continuous cycle starts with

“Start ” switch

4. Continuous cycle stops with

“Stop” switch

4 2

51

3

1Y1

0 %

1V1




95/164

Continuous operationLS1 LS2

1 A +24V

ART K2 K2 K1 K1

1 2 3 4 5


4 2

51

3

1Y1

0 %

1V1

0V

STOP

K2

LS1 LS2

K1 1Y1

23

45

NikiniNikiniNikiniNikiniMemory Circuit with

Do ble Solenoid Val e


96/164

Double Solenoid Valve

+24V

S1 S2

1 21 A


0V

1Y1 1Y2

4 2

5

1

3

1Y1 1Y2

5 0 %

1V1

NikiniNikiniNikiniNikiniHeavy Work piece feeding

C ti ti


97/164


1. Piston moves forward when

it reaches 1B1

2. Return to initial position


automatically when piston

moved to 1B2


“Start ” switch


“Stop” switch

NikiniNikiniNikiniNikiniContinuous operation with

D bl S l id V l


98/164

Double Solenoid Valve+24V

ART K1 K1 LS2

1 2 3 4


0V

STOP

1Y1 1Y2K1

LS1

23


Timers


99/164

Timers



Delay On Timer


100/164

Delay On Timer

• S1 ON; T1 contact

turns on after a delay

• S1 OFF; Immediately


T1 contact turns off

S1

T1

Contact

Delay


Delay Off Timer


101/164

Delay Off Timer

• S1 ON; T1 contact ON

• S1 OFF; T1 contact

turns off after a delay


S1

T1

Contact Delay


Counter


102/164

Counter



Counter


103/164

Counter

Up counter

• S1(Pulse); C.V =>+1

• R1 Pulse ; C.V => 0


• C.V >= P.V; C1

contact switches

NikiniNikiniNikiniNikiniContinuous operation

1 Pi t f d ft


104/164

1. Piston moves forward after

pausing 2 Sec at 1B1

2. Return to initial positionautomatically when piston

moved to 1B2



“Start ” switch


“Stop” switch or stops

automatically after 5 cycles

5. S3 detent Switch is used to

pause the cycle.


Timer-Counter Exercise


105/164

Timer Counter Exercise



Timer-Counter Exercise


106/164

Timer Counter Exercise



Multi Actuator Systems


107/164

Multi Actuator Systems

• Sequential logic control

• Combinational logic control



Sequential control


108/164

Sequential control



Vertical Displacement


109/164

Vertical Displacement2A (B)


1A

(A)


Design steps


110/164

es g steps

1. Sketch the system

2. Identify the sequence3. Design the (pneumatic) power circuit.


4. Identify the input signals & Output Signals

5. Design the control circuit according to thecontrol requirement.

6. If there are signal overlaps, necessary actions

should be taken to overcome signal overlapproblems.


Displacement-step diagram


111/164

p p g


NikiniNikiniNikiniNikini1A+ 2A+ 1A- 2A- With Single

Solenoid valves


112/164

1S1 1S2 2S1 2S2

1A (A) 2A (B)

Solenoid valves


Pneumatic Circuit

4 2

5

1

31Y1

4 2

5

1

32Y1

5 0 % 5 0 %

1V1 2V1


113/164


Solenoid valves: with limit switches


114/164

+24V

START K1

2S1

1S2 K2 K1 K2

2S2

1 2 3 4 5 6


Electrical Circuit

0V

K1 K2 1Y1 2Y1

25

46


Solenoid valves: with sensors


115/164



1A+ 2A+ 1A- 2A- With DoubleSolenoid valves


116/164

Solenoid valves

1S1 1S2 2S1 2S2

1A (A) 2A (B)


Pneumatic Circuit

4 2

5

1

31Y1 1Y2

4 2

5

1

3

2Y1 2Y2

5 0 % 5 0 %

1V1 2V1


117/164

NikiniNikiniNikiniNikiniA+ B+ A- B- With Double

Solenoid valves


118/164


Electrical Circuit


Drilling Application


119/164

Drill Cylinder Limit switches to

detect end limits of cylinder movement

2.0


Clamp

Cylinder

1.0


Solenoid valves


120/164


Pneumatic Circuit


Drilling -Control diagram


121/164



Solenoid valves


122/164


Electrical Circuit

NikiniNikiniNikiniNikini1A+ 2A+ 2A- 1A- With Double

Solenoid valves


123/164

1S1 1S2 2S1 2S2

1A (A) 2A (B)


Pneumatic Circuit

4 2

5

1

31Y1 1Y2

4 2

5

1

3

2Y1 2Y2

5 0 %

5 0 %

1V1 2V1


124/164

NikiniNikiniNikiniNikini1A+ 2A+ 2A- 1A- Double

Solenoid valves-Shift Register


125/164

+24V

K2

1S1

K1 K2 K3 K4 K1 K3 K4TART

K1 K2 K3

1S2 2S2 2S1 S2

1 2 3 4 5 6 7 8 9 10 11 12 13


Electrical Circuit

0V

2Y2 1Y21Y1 2Y1K1

K3

K2

K4

K3

K1

K4

K4

K2

2310

7 4511

1 6712

3 1813

5

NikiniNikiniNikiniNikiniModern Electropneumatic Control

Systems


126/164

• The most important objectives in all

developments in electropneumatics:– Reduction of overall costs of an


electropneumatic control system

– Improvement of the system's performance data

– Opening up of new fields of application


Cost Reduction


127/164

• The design of present-day electropneumatic

control systems is primarily aimed atreducin the cost of:


– project planning

– installation

– commissioning

– maintenance.

NikiniNikiniNikiniNikiniImprovement of the system's

performance data


128/164

• Examples of how the performance data of

pneumatic components can be improvedinclude:


– Reducing cycle times by increasing motion

speeds

– Reducing mounting space and weight

– Integration of additional functions, such aslinear guides

NikiniNikiniNikiniNikiniOpening up of new fields of

application


129/164

• Applications in which speeds, positions and forces arecontinuously set and monitored by an electrical controlsystem have so far been the preserve of electrical andhydraulic drives.


• The development of low-cost proportional valves andpressure sensors makes it feasible today to use pneumaticdrives in many applications.

• A new market for pneumatics is emerging as a result.

• Although this market is small in comparison with the

market for classical electropneumatic controls, it ischaracterized by strong growth.


Proportional pneumatics


130/164

• Proportional pneumatics is primarily used in

the following fields of application:– Continuous ad ustment of ressures and forces


– Continuous adjustment of flow rates and speeds

– Positioning with numerically controlled drives,

such as in robotics

NikiniNikiniNikiniNikiniProportional pressure regulating

valves


131/164


NikiniNikiniNikiniNikiniProportional pressure regulating

valves


132/164

• A proportional pressure valve converts a

voltage, its input signal, into a pressure, itsout ut si nal.


• The pressure at the output to a consuming

device can be adjusted continuously from 0

bar to a maximum of, for example, 6 bar.


133/164

NikiniNikiniNikiniNikiniProportional directional control

valves

A i l di i l l l bi


134/164

• A proportional directional control valve combines

the properties– electrically actuated switching directional control valve


– Electrically adjustable throttle (Flow control valve)

• The connections between the valve ports can beopened and shut off.

• The flow rate can be varied between zero and the

maximum value.

NikiniNikiniNikiniNikiniProportional directional control

valves

A i l di i l l l ll


135/164

• A proportional directional control valve allows

continuous adjustment of the valve flow rate=> continuous adjustment of the speed of travel of the


p ston ro o a pneumat c cy n er

• The speed characteristic can be optimized– Enables high speeds with gentle acceleration and

braking

• Applications are found in conveying sensitivegoods (for example in the food industry).

NikiniNikiniNikiniNikiniOptimized valves for block

mounting

I d d i


136/164

• Improved dynamic response

– Through short switching times and high flow rate

• Reduced compressed air consumption


– Through reduced volume of air between valve and

drive unit• Reduced cost of the power supply unit

– Through lower electrical power consumption

• Less mounting space and minimized weight


mounting

P ti l l l l i d ti


137/164

• Particularly low-loss air ducting

• Very compact dimensions


.

• A block may consist of the following:– Directional control valve modules

– Modules for pneumatic connection

– Modules for electrical connection


mounting


138/164

a) Valve module


b) Air supply and

silencer mountingon an end face c) Air supply and

silencer mounting

on underside

NikiniNikiniNikiniNikiniElectrical connection of valve blocks

and valve terminals


139/164

a) Individual connection


w separa e connec or

for each solenoid coil

b) Multi-pin plug connection

c) Fieldbus connection

d) Actuator-sensor interface

NikiniNikiniNikiniNikiniElectrical connection of valve blocks

and valve terminals1. With no additional connection module, each coil is


140/164

1. With no additional connection module, each coil isconnected individually via a separate cable socket.

2. Module for multi-pin connection: all solenoid coils areconnected to a single multi-pin plug within the valve


terminal .

3. Module for fieldbus connection: all solenoid coils areconnected to a fieldbus interface within the valveterminal.

4. Module for AS-i connection (actuator-sensor interface):

all solenoid coils are connected to the two interfaces forconnection of the actuator- sensor bus within the valveterminal.


Modern installation concepts• The use of advanced components in electropneumatics


141/164

The use of advanced components in electropneumaticsallows valves to e combined in valve terminals.

• The contacts of the solenoid coils engage directly into thecorresponding connection sockets on the valve terminals.


• The advantages are as follows:

– No need for terminal boxes and associated terminalsstrips.

– Faulty directional control valves and sensors can bereplaced without having to be disconnected from and

reconnected to terminals.– Wiring effort is reduced


) V l t i l


142/164

a) Valve terminal

and separatesensor connection unit


b) Valve terminal

with integrated

sensor connection unit

and integrated PLC


Layout of a Fieldbus system• The programmable logic controller and the


143/164

The programmable logic controller and the

valve terminals each have an interface bymeans of which they are connected to the


e us.

• Each interface consists of a transmittercircuit and a receiver circuit.

• The fieldbus transfers information between

the PLC and the valve terminals.


Layout of a Fieldbus system


144/164


The power for operating the

valves and sensor is transmittedvia the same cable.


Example Field BUS:AS-i


145/164


Directional control valve

with AS interface


Reducing wiring effort


146/164


a) Valve blocks with

conventional wiring

b) Valve terminal with multi-

pin plug connectionc) Valve terminal with fieldbus

connection

NikiniNikiniNikiniNikiniDocumentation for an

electropneumatic control system• Positional sketch


147/164

• Function diagram or function chart– representation of the control sequence


• Pneumat c an e ectr ca c rcu t agram

– representation of the interaction of all components• Terminal allocation list

– representation of the wiring allocation of terminal stripsin switchboxes and terminal boxes

• Parts lists


Positional sketchClamp CylinderSensors


148/164

p y

Metal Sheet


Sheet-metal bending device

Bending Cylinder


• Four steps are required for the bending operation:


149/164

• Step 1:– Advance piston rod of cylinder 1A (clamp workpiece)

•


– Advance piston rod of cylinder 2A (bend metal sheet)

• Step 3:– Retract piston rod of cylinder 2A (retract bending

fixture)

• Step 4:– Retract piston rod of cylinder 1A (release workpiece)


Displacement-step diagram


150/164


• The movements of the piston rods are shown.

• The individual movement steps are numbered consecutively from leftto right.

• If there is more than one power component, the movements of thepiston rods are plotted one below the other.


Displacement-time diagram


151/164


• The movements of the piston rods are plotted as a functionof time.

• This highlights the different lengths of time needed forindividual steps.


Function Chart


152/164



153/164


Electrical Signal Processing


154/164


Signal Input Signal processing Signal output


Programmable Signal ProcessingProgrammable

Mi


155/164

Microprocessor

system


Signal Input Signal processing Signal output


Programmable logic controllers• Programmable logic controllers (PLCs) are


156/164

used for processing of signals in binarycontrol s stems.


• The PLC is particularly suitable for binary

control systems with numerous input and

output signals and requiring complex signal

combinations.


PLC driven Electric drives


157/164




158/164




159/164



Advantages of PLC• Greater reliability and longer service life

– no moving contacts


160/164

g

• Less project planning work– tested programs and subprograms can be used for a


number of different control setups

– but each relay control circuit has to be wired and tested

from scratch• Faster control development

– programming and wiring can be carried out in parallel

• Simpler monitoring of stations by a higher-level host

computer– a programmable logic controller can easily exchange

data with the host computer


• PLC is the most cost-effective solution for


161/164

implementation of a signal processing system.– hardware costs


– project planning

– setting up– commissioning

– maintenance

• Today's electropneumatic control systems aretherefore almost always equipped with a PLC.


Review Introduction to Electro-pneumatics systems


162/164

Switches and Sensors Reco nizin and drawin of electrical s mbols


Electrical Signal processing

Electro-pneumatic actuators

Solving simple control problems using electro-

pneumatics

Solving control problems using multi actuator

electro-pneumatic systems



163/164

Questions??




164/164


Documents

Electropeneumatics