ee061 pneumatic controls pr inst

7/25/2019 EE061 Pneumatic Controls Pr Inst

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SRI LANKA INSTITUTE of ADVANCED TECHNOLOGICAL EDUCATION

Training Unit

Pneumatic Controls

Practice

No: EE 061

ELECTRICAL and ELECTRONIC

ENGINEERING

Instructor Manual


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Training UnitPneumatic Controls

Practical Part

No.: EE 061

Edition: 2009Al l Rights Reserved

Editor: MCE Industrietechnik Linz GmbH & CoEducation and Training Systems, DM-1Lunzerstrasse 64 P.O.Box 36, A 4031 Linz / Austr iaTel. (+ 43 / 732) 6987 3475Fax (+ 43 / 732) 6980 4271Website: www.mcelinz.com


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PNEUMATIC CONTROLS

LIST OF CONTENT

CONTENTS Page

Introduction ...........................................................................................................................4

General Information...........................................................................................................4

Safety ................................................................................................................................6

Performing Exercises ........................................................................................................6

Commissioning..................................................................................................................7

Exercise 1 Direct control of a single-acting cylinder, extending ......................................9

Exercise 2 Direct control of a single-acting cylinder, retracting.....................................11

Exercise 3 Indirect control of a single-acting cylinder ...................................................14

Exercise 4 Regulating the speed of a single-acting cylinder.........................................17

Exercise 5 Slow-speed extension, rapid retraction of a single-acting cylinder.............. 20

Exercise 6 Direct control of a double-acting cylinder with push-button.........................23

Exercise 7 Indirect control of a double-acting cylinder..................................................26

Exercise 8 Speed regulation of a double-acting cylinder ..............................................28

Exercise 9 Controlling a double-acting cylinder, impulse valve, 2 push-buttons...........31

Exercise 10 Displacement-dependent control of a double-acting cylinder, impulse valve ..

.....................................................................................................................34

Exercise 11 Controlling a double-acting cylinder, impulse valve, 2 reflex nozzles..........37

Exercise 12 Stop control, double-acting cylinder with 5/3 directional control valve, tensile

load .....................................................................................................................41


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Exercise 13 Pressure-dependent control of 1 double-acting cylinder .............................45

Exercise 14 Time-dependent control of 1 double-acting cylinder....................................49

Exercise 15 Logical control with shuttle and twin-pressure valves..................................53

Exercise 16 Sequential control of 2 double-acting cylinders without overlapping signals...

.....................................................................................................................57

Exercise 17 Sequential control of 2 double-acting cylinders with signal overlapping, rollers

with idle return.....................................................................................................................61

Exercise 18

Sequential control of 2 double-acting cylinders with signal overlapping,change-over valve...............................................................................................................65


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Introduction

General Information

The exercises to be found in this brochure "Rexroth Practice for Professionals -

Pneumatics" correspond to the exercises of "bungsreihe Pneumatik" [Training series

"Pneumatics"] published by the Bundesinstitut fr Berufsbildung (Federal Institute for

Vocational Training) in Berlin.

The exercises were extended in respect to the technological further developments in

pneumatic control technology and new exercises were added to the practice series.

For practical exercises, a practice System and the basic kit for pneumatics under the BIBBorder number 0827 003 365 are available.

In order to achieve the best practical results, the basic kits include only industrial

components. The components are equipped with a patented "Snap-in" system and can be

easily and quickly attached to the base plate by the user in the exercises.

The following features characterize the practice system:

- The base plate is a grooved plate. lt provides the advantage of being able to position

the components infinitely and allows a variable arrangement on the plate.

- The grooved plate can be used horizontally on a lab table to do practical exercises.

The air service unit can be tilted to a 45 degree angle and thus can be optimally

mounted on the horizontal plate.

- The mobile "DS3 synergy" system uses various table and accessory modules to create

various set-ups.

- The grooved plate can also be used in a vertical or tilted position.

- The "Snap-in" system allows all components to be easily attached and in some cases

be turned at a 90 degree angle. In this manner the space on the plate can be used

more effectively.

- Valves of various nominal sizes with quick-release coupling attached are used. The

elements are connected by plastic tubes of the same diameter.

- All cylinders used have a piston diameter of 25 mm. Single-acting cylinders have a

stroke length of 50 mm, the double-acting cylinders of 100 mm and are spring

cushioned.


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- For exercises in connection with electro-pneumatic components, the double-acting

cylinders are equipped with proximity switching through an annular magnet

encapsulated in the piston.

Base plate and basic kit for the practical exercises

Description Order No.

Grooved plate LT 0 827 003 702

Basic kit Pneumatics BIBB 0 827 003 365

Optional Equipment and Accessories

Description Order No.

DS3 Basic frame 0 827 003 701

Grooved plate ERGO 0 827 003 717

Mobile file 0 827 003 707

Writing support 0 827 003 705

Information board (A4-sheet holder) 0 827 003 721


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Safety

In general there are no real dangers when doing exercises with pneumatic components.

Nevertheless, all piping work should principally be executed with the air pressure turned off

(ball valve an the air-service unit should be closed).

Please regard the following measures in any case:

- The locking plugs on the quick-release couplings of distributor and components should

be properly secured!

- Plastic tubes that come loose from quick-release couplings when pressure is applied

have a "lashing effect" (protect eyes!).

- When detaching tubes under pressure, use one hand to press the release ring and the

other to pull out the end of the tube, holding it tightly.- lt is possible that cylinders will independently start to move when turning on the air

pressure.

- Do not try and touch any moving parts (piston rod, switching cam). This could cause

painful injuries by pinching your finger between the limit switch and switching cam.

Performing Exercises

- For optimum, synergetic and successful learning within a reasonable exercise time, two

students should work together at a practice unit at a time.

- The equipment to be used is listed in the equipment list in the instructions.

- The arrangement of the equipment on the base plate should be executed according to

the arrangement sketch that goes with each exercise.

- The components are attached by snapping them properly onto the grooves in the

grooved plate.

- The exercise is to be circuited according to the circuit diagram with plastic tubes and T-

distributors.

- The plastic tubes are to be stuck into the quick-release coupling with light pressure. To

detach the tubes, briefly press the release ring with one hand and remove the tube with

the other.

- Note: to avoid the plastic tubes from getting stuck, frequently cut off the end of the tube

with the tube cutter.


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- Pay attention to optimum error detection: when an error occurs, do not pipe the

exercise again, even in the most complicated circuits that are already mounted, but

rather use the systematic error analysis to find the error and eliminate it.

- Further notes an executing the exercises, as well as written and graphic evaluation can

be found in the instructions in each description.

Commissioning

- For each exercise unit, a pressure supply of 6 to 8 bar, without lubrication, should be

available, with a suction capacity of 50 to 100 NI/min.

- The system pressure at the work-place should be set an the air regulator as a standard

of pe= 5 bar.- All piping work should be carried out without pressure (ball valve an the air service unit

should be closed).

- Any air escaping through open quick-release couplings or from plastic tubes causes a

drop in pressure, especially when several workplaces with relatively low supply

capacity and insufficient storage volume are in operation.


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Basic Kit Pneumatics BIBB Order No. 1 827003 365, List of Components

Qty. Description Order No. Comp. No.

1 Air service unit with 3/2 directional control ball valve, G1/8, 0.5- 10 bar

1 827 003 410 1

1 Distributor, 6-fold, self-closing couplings 1 827 003 411 21 Cylinder, single-acting with return spring, = 25 mm, stroke =

50 mm1 827 003 371 3

3 Cylinder, double-acting, with adjustable spring cushioning andfor proximity switching, = 25 mm, stroke = 100 mm

1 827 003 372 4

1 Cylinder, double-acting with adjustable spring cushioning andfor proximity switching, = 25 mm, stroke = 100 mm, with anattachment for tensile load 3.4 kg

1 827 003 373 5

2 3/2 directional control valve M5, manually operated with push-button, closed neutral position

1 827 003 392 6

1 3/2 directional control valve G1/8, manually operated withpush-button, flow in both directions

1 827 003 393 7

1 5/2 directional control valve G1/8, manually operated withpush-button

1 827 003 396 8

1 3/2 direct. control valve G1/8 with restoring spring, pneum.

operated, flow in both directions

1 827 003 374 9

1 5/2 directional control valve G 1/8 with restoring spring,pneumatically operated

1 827 003 376 10

3 5/2 directional control impulse valve G1/8, pneumaticallyoperated

1 827 003 377 11

1 5/3 directional control valve G1/8, pneumatically operated,mid-position closed

1 827 003 378 12

4 3/2 directional control valve M5, mechanically operated, roller,closed neutral position

1 827 003 399 13

2 3/2 direct. control valve M5, mech. operated, idle return roller,closed neutral position

1 827 003 401 14

2 Flow control valve with non-return G1/8, hose version 1 827 003 379 151 Quick-exhaust valve G1/4 1 827 003 381 161 3/2 directional control time delay valve, G1/8, flow in both

directions, 0.15 - 55 s

1 827 003 385 17

2 Shuttle valve (OR) G 1/8, 1-fold 1 827 003 382 185 Twin-pressure valve (AND) G 1/8, 1-fold 1 827 003 383 191 Pressure display, pneumatic, red, minimum pressure 1.2 bar 1 827 003 409 203 Pressure gauge 0 - 10 bar 1 827 003 406 211 Pressure switch with 3/2 directional control valve function,

adjustable 2-8 bar1 827 003 388 22

1 Pressure control valve with pressure gauge, G1/8, 0.5 - 10 bar 1 827 003 386 231 Pressure control valve for low pressure, with pressure gauge,

G1/8, 0 - 1 bar1 827 003 387 24

2 Reflex nozzle, min. pressure, 0.4 bar 1 827 003 403 252 3/2 amplifier for reflex nozzle, 2-stage, G 1/8, X=12 - 500 mbar 1 827 003 389 261 Step sequence for 4 steps and check step, M5 1 827 003 390 2725 Blanking plug, tube diameter 4 mm 1 823 105 006 ---

5 Two-way plug, tube diameter 4 mm 1 823 391 629 ---5 T-connection for plastic tubing 4 mm 1 823 381 043 ---

25m Plastic tubing 4 x 1; calibrated on the outside, PU black 1 820 712 010 ---2m Plastic tubing 6 x 1; calibrated on the outside, PU black 1 820 712 012 ---1 Tube cutter for plastic tubes 1 827 391 390 ---


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Exercise 1 Direct control of a single-acting cylinder, extending

Aim

This exercise provides basic know-how and skills on the set-up and operation of pneumatic

controls using the control of a single-acting cylinder as an example.

Suggestion for the positioning of equipment on the working plate

Pneumatic circuit diagram

List of equipment

Pos. Qty. Description01 1 Air service unit

(filter with waterseparator, pressureregulator andpressure gauge)with 3/2 directionalcontrol ball valve

02 1 Distributor, 6-fold03 1 Single-acting

cylinder06 1 3/2 directional

control valve withmanually operatedpush-button

21 1 Pressure gaugeAccessories


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Task

- The piston rod of the single-acting cylinder (Z1) should extend after the button (S1) has

been actuated and remain extended as long as the button is pushed.

- The active pressure that is placed on the cylinder piston should appear on the pressure

gauge.

- The pressurized air is supplied by an air service unit (filter with water separator,

pressure regulator and shut-off valve) and by the compressed-air distributor.

- The circuit diagram is to be drawn or additions made using symbols and port symbols

according to ISO 1219 and RP68P.


- The piston rod of the single-acting cylinder Z1 extends after pushing the button S1 and

remains in that position as long as the button is pushed.

- A pressure gauge registers the active pressure on the cylinder piston.

Didactic notes

- This simple exercise helps get the student acquainted with the practical use of the

practice unit and components.

- The student performs the proper setting of the working pressure on the air service unit

and practices the use of plastic tubes and quick-release couplings.

- Before starting the first exercise, the participant should be informed of the procedure as

well as the security measures involved.

Instructions

- The arrangement of the equipment on the working plate should be as shown in the

arrangement sketch.

- The working pressure of pe = 5 bar is to be set at the pressure regulator of the air

service unit.

- The components are to be connected with plastic tubes and accessories according to

the circuit diagram.

- The working pressure is switched on with the ball valve.- The exercise is started and the proper function is checked.

Conclusion

A single-acting cylinder can basically only be controlled with a 3/2 directional control valve.

Corresponding to the basic position of the single-acting cylinder (piston rod retracted) a 3/2

directional control valve in locked, neutral position (n.c. = normally closed) should be

mounted.


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Exercise 2 Direct control of a single-acting cylinder, retracting

Aim

This exercise demonstrates the use of a 3/2 directional control valve with flow in both

directions functioning as an open neutral position valve of a single-acting cylinder extended

in neutral position.

Suggestion for the positioning of equipment an the working plate


List of equipment

Pos. Qty. Description01 1 Air service unit

(filter with waterseparator,pressureregulator andpressure gauge)with 3/2directional controlball valve

02 1 Distributor, 6-fold

03 1 Single-actingcylinder

07 1 3/2 directionalcontrol valve withmanuallyoperated push-button, flow inboth directionsAccessories


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Task

- The basic position of the piston rod of the single-acting cylinder (Z1) is extended after

switching on the compressed air supply.

- After actuating the push-button (S1) the piston of the single-acting cylinder should

retract and remain retracted as long as the button S1 is pushed.

- The pressurized air is supplied by an air service unit (filter with water separator,

pressure regulator and shut-off valve) and by the pressure distributor.

- The circuit diagram is to be drawn or additions made using symbols and port symbols

according to ISO 1219 and RP68P.


- After switching on the pressure by opening the 3/2 directional control ball valve, the

piston of the single-acting cylinder extends.

- After pushing the button S1 (3/2 directional control valve), the piston rod of the single-acting cylinder Z1 retracts and remains retracted as long as the button S1 is pushed.

Didactic notes

- In addition to the 2 types of seat constructions for 3/2 directional control valves, closed

neutral position or open neutral position, the spool valve design is also available.

- One advantage of the spool valve is that the valve principally allows "flow" in both

directions.

- This type of valve can therefore be applied in an open neutral position or also in the

closed neutral position.

- Technical notice referring to the equipment: the designation of symbols for ports for

spool valves with flow in both directions is often found in different manners:

in some cases only the symbol indicates this design, but often the ports are marked

with 1/3 or 3/1 or 1 (3) or 3 (1).

- In the case of servo valves, a mechanical alteration is often necessary (for example

twisting the servo head) in addition to exchanging the two ports 1 and 3.

- In the circuit diagram the solution with a manually operated 3/2 directional control valve

in open neutral position is to be considered as correct.

Instructions


arrangement sketch.


service unit.


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- The components are to be piped according to the circuit diagram with plastic tubes and

accessories.

- The working pressure is switched on with the ball valve.

- The exercise is started and the proper function is controlled.

Conclusion

In addition to the 3/2 directional control valves in closed neutral position (or n.c.) there are

also directional control valves with open neutral position, (n.o. normally open). When a

pneumatic circuit diagram is marked as "pressure-free" (3/2 directional control ball valve on

"off"), then the cylinder also must be pictured in the pressure-free condition, i.e. the piston

rod is retracted .


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Exercise 3 Indirect control of a single-acting cylinder

Aim

This exercises conveys know-how on the indirect control of cylinders, using a single-acting

cylinder and a pneumatically operated 3/2 directional control valve as an example.



List of equipment

Pos. Qty. Description

01 1 Air service unit(filter with waterseparator, pressureregulator andpressure gauge)with 3/2 directionalcontrol ball valve

02 1 Distributor, 6-fold03 1 Single-acting

cylinder06 1 3/2 directional

control valve withpush-button, closed

neutral position09 1 Pneumatically

operated 3/2directional controlvalve, closedneutral positionAccessories


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Task

- The piston rod of a single-acting cylinder (Z1), retracted in neutral position, should

advance after pushing an easily pressed button (S1).

- Note: for the control of a large-volume cylinder (with a large piston diameter) an

accordingly dimensioned directional control valve is necessary.

- The cylinder is mounted a slight distance from the button (S1).

- After releasing the manual push-button, the piston of the cylinder should retract

automatically into its back position.

- Additions to the circuit diagram.

- All connections should be marked with the port symbols according to ISO 5599 or RP

68 P.


- A manually operated 3/2 directional control valve in closed neutral position (start buttonS1) applies pressure to a pneumatically operated 3/2 directional control valve.

- A large volume single-acting cylinder is controlled via a pneumatically operated 3/2

directional control valve (pos. 9), the piston rod extends.

Didactic notes

- Basic knowledge of the dimensioning of pneumatic components is a prerequisite for

understanding this exercise.

- lt should be pointed out that in practice it is necessary to use plastic tubes of different

dimensions and colors.

- Circuit diagram: control lines are the connecting lines between the output of signalling

elements (for example button S1) and the pneumatic actuation ports of the actuators

(for example pneumatically operated 3/2 directional control valve, port 12). These

connecting lines are to be drawn as dotted lines.

- The air pressure line to the signalling elements is also often dotted.

- Note: therefore it is especially important that the participants understand the topics

"servo valves" and "indirect control of cylinders" and do not confuse the two.

- The main reason for using indirect control in pneumatics: large volume, single-actingcylinders should be able to be controlled with a small dimensioned directional control

valve at acceptable working speed. In addition, the button can also be mounted

somewhat farther away from the cylinder (for example a button built into a control

panel).


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Instructions


arrangement sketch.


service unit.


accessories.


- The exercise is started and the proper function is controlled.

Conclusion

Large volume cylinders cannot be directly controlled with small-dimensioned directional

control valves. These cylinders are therefore indirectlycontrolled through the installation

of pneumaticallyoperated 3/2 directional cont rol valvesin a size corresponding to thecylinder size.


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Exercise 4 Regulating the speed of a single-acting cylinder

Aim

This exercise demonstrates the application of a one-way flow control valve to infinitely

adjust the speed of a single-acting cylinder.



List of equipment

Pos. Qty. Description01 1 Air service unit (filter

with water separator,pressure regulatorand pressure gauge)with 3/2 directionalcontrol ball valve

02 1 Distributor, 6-fold03 1 Single-acting cylinder07 1 3/2 directional control

valve with push-button, closed neutral

position15 1 Flow control valvewith non-return,adjustable

21 2 Pressure gaugeAccessories


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Task

- The extension speed of the piston rod of a single-acting cylinder (Z1), retracted in its

neutral position, should be infinitely adjustable.

- The retraction of the piston rod occurs at normal speed. The retraction speed is not

adjustable.

- The cylinder is controlled with a manually operated button (S1). After releasing the

button, the piston of the cylinder should retract automatically into its back position.


- All connections should be marked with the connection symbols according to ISO 5599

or RP 68 P.

Pneumatic circuit d iagram

- A single-acting cylinder Z1 is directly controlled via a pneumatically operated 3/2

directional control valve (S1).- A flow control valve with non-return is built into the working line between the cylinder

and the control valve which enables the piston rod to extend with infinitely adjustable

speed and to retract with normal speed (through spring force).

- The flow control valve with non-return is mounted in such a way that the air flowing into

the cylinder is restricted (supply air restriction).

- Two pressure gauges indicate the pressure before and alter the flow control valve with

non-return.

Didactic notes

- If there is no port symbol on the flow control valve with non-return, then the direction of

the symbol on the valve is considered that of the flow control valve with non-return.

That is the reference for the correct mounting of the element.

- If the flow control valve with non-return is closed all the way or otherwise blocked

(particles in the throttle) then the cylinder can only retract but not extend.

Instructions

- The arrangement of the equipment on the working plate should be as shown in thearrangement sketch.


service unit.


accessories.


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- The knurled-head screw on the flow control valve with non-return should be unscrewed

as far as possible (counter-clockwise).


- Actuate S1, observe the retraction and extension speeds.

- When frequently changing the setting of the flow control valve with non-return, observe

both speeds (when retracting and extending) as well as the pressure on both pressure

gauges.

Conclusion

Flow control valves with non-return are used to achieve infinitely adjustable speed

regulation of the piston rod movement. The flow control valves with non-return are

mounted in the working lines between the directional control valve and cylinder. For a

single-acting cylinder the supply air restrictionis used for the extending movement.


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Exercise 5 Slow-speed extension, rapid retraction of a single-acting cylinder

Aim

In addition to throttling the cylinder speed, this exercise shows how to achieve the highest

possible speed when retracting the piston rod by using a quick-exhaust valve.

Suggestion for the positioning of equipment an the work ing plate


List of equipment



02 1 Distributor, 6-fold03 1 Single-acting cylinder07 1 3/2 directional control

valve with push-button, closed neutral

position15 1 Flow control valveswith non-return,adjustable

16 1 Quick-exhaust valveAccessories


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Task

- The piston rod of a large volume, single-acting cylinder (Z1) is to extend with restricted,

adjustable speed.

- The retraction of the piston rod should occur at the highest possible speed, also when

the directional control valve (S1) is mounted a distance away from the cylinder.

- The cylinder is controlled by a manually operated button (S1). After releasing the

button, the piston rod should retract automatically into its back position.



or RP 68 P.


- Via the flow control valve with non-return mounted in the working line the speed of the

piston rod when extending can be infinitely restricted.- Through the quick-exhaust valve, also mounted in the working line (as near to the

cylinder port as possible), the cylinder piston retracts with the maximum possible

speed.

Didactic notes

- In practice, the valves are screwed directly on to the cylinder port with a double nipple

(with the exception of miniature quick-exhaust valves for tubes with a diameter less

than 3 mm).

- Depending on the diameter of the cylinder and the piston rod speed, a loud exhaust

noise can be heard when pressure is released from the quick-exhaust valve. An

exhaust silencer should be available in such cases to protect those persons working

there.

- Quick-exhaust valves are also used in cases where pressure needs to be quickly

released (for example they are installed in pneumatic two-hand safety controls).

Instructions

- The arrangement of the equipment on the working plate should be as shown in thearrangement sketch.


accessories.

- The knurled-head screw on the flow control valve with non-return should be unscrewed

as far as possible.



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- Actuate S1, observe the retraction and extension speeds.

- When frequently changing the setting of the flow control valve with non-return, make

sure to observe both speeds.

Conclusion

The highest possible speed of the piston rod can be achieved by mounting a quick-

exhaust valvein the corresponding working lineof a cylinder.

The pressure release of the cylinder volume then occurs directly via the exhaust vent port

3of thequick-exhaust valve. The quick-exhaust valve is mounted directly at the cylinder

port.


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Exercise 6 Direct control of a double-acting cylinder with push-button

Aim

This exercise provides know-how on the direct control of double-acting cylinders with

manually operated 5/2 directional control valves.

In addition, the effect of adjustable spring cushioning in double-acting cylinders can be

observed.



List of equipment



02 1 Distributor, 6-fold04 1 Double-acting

cylinder withadjustable springcushioning

08 1 5/2 directional controlvalve with push-buttonAccessories


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Task

- The piston rod of a double-working cylinder (Z1) should extend after actuating a button.

- After releasing the button (S1), the piston of the cylinder should retract automatically to

its back position.



or RP 68 P.


- The cylinder is retracted in neutral position.

- The double-acting cylinder is directly controlled by a manually operated 5/2 directional

control valve (pos. 8).

- The spring cushioning mounted in the cylinder can be adjusted.

Didactic notes

- At the end of the exercise, refer to the 4/2 directional control valve and explain the

difference between the two valve designs.

- Explain the features of the various spool designs (soft-sealing spool, metal spool) of

5/2 directional control valves.

- A watchmaker's screwdriver is necessary for adjusting the set screw of the spring

cushioning.

lnstructions


arrangement sketch.


accessories.


- Check and see if the cylinder is retracted in neutral position and that pressure is

applied to it in this position.

- Actuate S1.- Check the proper sequence.

Extra experiment:

- Set the greatest possible working pressure on the pressure regulator.

- Both set screws of the spring cushioning are to be unscrewed with a screwdriver as far

as possible (counter-clockwise).


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- Trigger the cylinder and observe how hard the piston hits the end positions.

- Adjust spring cushioning to a higher level and observe the effect of the spring

cushioning.

Conclusion

The control of a double-acting cylinder occurs principally through a 5/2 directional control

valveas an actuator.

In the basic setting (spring position) of a 5/2 directional control valve supplied with

compressed air at port 1, port 2 is always "pressurized" and port 4 always "vented".


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Exercise 7 Indirect contro l of a double-acting cylinder

Aim

This exercise demonstrates the indirect control of a double-acting cylinder with a

pneumatically operated 5/2 directional control valve.



List of equipment


01 1 Air service unit (filterwith water separator,pressure regulator andpressure gauge) with 3/2directional control ballvalve

02 1 Distributor, 6-fold04 1 Double-acting cylinder

with adjustable springcushioning

10 1 Pneumatically operated5/2 directional controlvalve

06 1 3/2 directional controlvalve with push-button,closed neutral positionAccessories

Task

- The piston rod of a double-acting cylinder (drive element Z1), retracted in neutral

position, should extend after actuating a button (controlling element S1).


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- Control of the cylinder (Z1) should occur indirectly.

- After releasing the push-button (S1), the piston of the cylinder should retract

automatically to its back position.

- Additions to the circuit plan.


or RP 68 P.


- A pneumatically operated 5/2 directional control valve (actuator) is controlled with a

manually operated 3/2 directional control valve (signalling element S1).

- The piston rod of the double-acting cylinder (actuating drive Z1) extends.

Didactic notes

- Point out how the control sequence is broken up into different components:signalling elements (signal input) control elements (signal processing) actuators (signal

output) drive elements (execution of the movement)

- Point out the signal flow direction of the signalling elements up to the drive element.

- This breakdown into components and the signal flow direction should also be depicted

in the pneumatic circuit diagram.

lnstructions

- The arrangement of the equipment an the working plate should be as shown in the

arrangement sketch.


accessories.

- The working pressure is switched an with the ball valve.

- Check and see if the cylinder is retracted in neutral position and that pressure is

applied to itin this position.

- Actuate S1.

- Control the proper sequence.

Conclusion

Air-actuated 5/2 directional control valves are, as all other pneumatically operated

directional control valves, controlled with a 3/2 directional control valveas a signalling

element. The function of the signalling elements (model of the 3/2 directional control valve)

is principally always the closed neutral posit ion (n.c.).


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Exercise 8 Speed regulation of a double-acting cylinder

Aim

In this exercise, the various types of speed regulation (throttling) of the piston rod

movements of double-acting cylinders with one-way flow control valves are looked at and

the effects are observed.



List of equipment

Pos. Qty. Description04 1 Double-acting cylinder


08 1 5/2 directional controlvalve with push-button

15 2 Flow control valveswith non-return,adjustableAir service unit,pressure distributorand accessories (notincluded in the circuitdiagram)


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Task

- The extension speed and the retraction speed of the piston rod of a double-acting

cylinder (drive element Z1), retracted in neutral position, should be infinitely adjustable.

- The movement of the piston rod is not allowed to be a jerky movement, neither when

extending nor when retracting.

- lt is assumed that the drive element (Z1) and the actuator (S1) are mounted at least 2 -

3 meters apart.

- The cylinder is controlled with a manually operated button (actuator S1). After releasing

the button (S1), the piston of the cylinder should retract automatically to its back

position.



or RP 68 P.

- Circuit 1:the speed of the cylinder piston is restricted when extending (restricting theexhaust) by mounting one flow control valve with non-return in the working line port 2 of

the 5/2 directional control valve.

- Circuit 2:the speed of the cylinder piston is restricted when retracting (restricting the

exhaust) by mounting one flow control valve with non-return in the working line port 4 of

the 5/2 directional control valve .

- Circuit 3:both speeds of the cylinder piston are restricted (both restricting the exhaust)

by mounting two flow control valves with non-return in both working lines of the 5/2

directional control valve.

- Circuit 4: the speed of the cylinder piston is restricted when extending (air supply

restriction) by mounting one flow control valve with non-return in the working line port 4

of the 5/2 directional control valve.

Pneumatic circuit diagrams

Didactic notes

- Explain the difference between the models "hose version" and "screw-in version" of

flow control valves with non-return.- Discuss advantages and disadvantages of speed regulation with flow control valves

directly mounted in the exhaust ports of the valve. Refer to the differences in the use of

this restriction of 4/2 or 5/2 directional control valves in this context.

- Also refer to the function of flow control valves in silencers or directly mounted in

valves.


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Instructions

- The 4 exercises are to be arranged and piped alter each other an the working plate.

- The working pressure is switched an with the ball valve.

- In all 4 exercises, the adjustment of the flow control valve with non-return is to be

changed.

Then observe and judge the movements of the piston and the effect an speed and jerk-

free movement.

Conclusion

In the case of double-acting cylinders, the speed regulation in both directions is usually

achieved by mounting two flow control valves with non-return in the working lines

between cylinder (actuating drive) and 512 directional control valve (actuator). Both flow

control valves with non-return are applied as a standard to restrict exhaust air flow .


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Exercise 9 Controlling a double-acting cylinder, impulse valve, 2 push-

buttons

Aim

In this exercise we examine how a pneumatically operated impulse valve functions when

controlling a double-acting cylinder.



List of equipment



11 1 5/2 directional controlvalve, impulse valve

15 2 Flow control valveswith non-return,adjustable

06 1 3/2 directional controlvalve, with manuallyoperated push-button

07 1 3/2 directional controlvalve, with manuallyoperated push-button,flow in both directionsAir service unit,pressure distributorand accessories (notincluded in the circuitdiagram)


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Task

- The piston rod of a double-acting cylinder (drive element Z1), retracted in neutral

position, should extend after actuating a button (signalling element S1) and remain

extended alter releasing the button (S1).

- After actuating a second button (signalling element S2), the piston rod of the cylinder

should again retract and also remain in this position, even when the button (S2) is no

longer actuated.

- The working speed of the cylinder should be able to be infinitely adjusted in both

directions.



or RP 68 P.


- By briefly actuating the button S1, the piston rod of the double-acting cylinder extends

to its front end position and remains in this position.

- Only when the button S2 is also briefly actuated does the piston rod retract back into its

initial position. The speed of both cylinder movements can be infinitely adjusted with

the flow control valves with non-return.

Didactic notes

- Discuss basic properties and cases of application of pneumatic impulse valves.

- Explain the cause and effect when both control ports of the impulse valve receive a

signal simultaneously.

- Concerning service and error detection in the case of pneumatic controls it should be

pointed out that an impulse valve has no defined basic setting.

Instructions


arrangement plan.

- The components are to be piped according to the circuit diagram with plastic tubes andaccessories.

- The working pressure is switched on with the ball valve. Observe whether the piston of

the cylinder remains in the back end position.

- Actuate S1 briefly and release, the piston of the cylinder extends.

- Actuate S2 briefly and release, the piston of the cylinder retracts.


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- When the piston of the cylinder is in the back end position, actuate S1 and continue to

press. Then additionally actuate button S2 and continue to press. Determine effects.

- Repeat the same experiment, but this time with an extended cylinder piston and first

continue to press button S2, then actuate button S1.

Conclusion

Impulse valves (e.g. 5/2 directional control impulse valves) store pneumatic signalsand

are always controlled with 2pneumatic signals (3/2 directional control valves). An impulse

valve remains in the actual switch position until it receives the opposite signal (without the

aid of pressurized air). An impulse valve therefore has no defined basic setting (= bi-

stable).


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Exercise 10 Displacement-dependent control of a double-acting cylinder,

impulse valve

Aim

The displacement-dependent control of a double-acting cylinder by using limit switches is

demonstrated in this exercise.


Example of application Functional diagram


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List of equipment Pneumatic circui t diagrams



11 1 5/2 directional control

valve, impulse valve15 2 Flow control valves

with non-return,adjustable

06 1 3/2 directional controlvalve, with manuallyoperated push-button

13 2 3/2 directional controlvalves, with roller

Air service unit,pressure distributorand accessories (not

included in the circuitdiagram)

Task

"Sheet-bending machine"

- A double-acting cylinder is used in a bending machine to form a metal sheet.

- The piston of the cylinder (Z1) extends when the button (S0) is actuated until it reaches

its front end position and forms the workpiece.

- Then the piston of the cylinder automatically retracts to its back end position.

- The working speed should be infinitely adjustable in both directions.- Additionally: the button (S0) is normally only actuated briefly. If the button remains

actuated the cylinder nevertheless must retract to its back end position.

- Develop the functional diagram with actuator and drive element.

- Drawing up the circuit diagram with symbols and port symbols according to ISO 5599

or RP 68 P.


- If the start button (S0) is actuated and the feeler roll (S1) mounted in the back end

position of the cylinder (Z1) is also actuated, then the signal reaches port 14 of the

impulse valve and switches it over, extending the piston rod.

- If limit switch S2 is contacted by the piston rod plunger, the signal arrives at port 12 of

the impulse valve, the impulse valve switches back to the right switch position, the

piston retracts.


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- The limit switch S1 is actuated in the back end position of the piston; now the control is

ready for a new start.

- The speed of both cylinder movements is infinitely adjusted with the flow control valves

with non-return.

Didactic notes

- lt is standard to use 3/2 directional control valves in closed, neutral position with

mechanical feeler roll actuation as limit switches for displacement-dependent

pneumatic controls.

- The limit switches are depicted in the lower level of the pneumatic circuit diagram like

all other signalling and connecting elements and not at their location of actuation!

- At the location of actuation only the symbol of the signalling element with a mark (short

line) is entered.

- In addition, a triangle is drawn at the front of the piston rod. This represents themechanical actuation by various parts such as cams, plungers, disks, etc.

Instructions


arrangement sketch.


accessories.


- When S0 is actuated and the limit switch S1 is mounted properly in the back end

position of the cylinder, the piston rod of the cylinder extends.

Conclusion

Mechanically actuated signalling elements are used as "limit switches" for displacement-

dependent controls.

A limit switch in neutral position can be actuated or not actuated. If a limit switch is

actuated in neutral position, then it will be depicted as actuated.


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Exercise 11 Controlling a double-acting cylinder, impulse valve, 2 reflex

nozzles

Aim

Introducing the pneumatic, proximity switching signalling technology with the example of

reflex nozzles and pneumatic amplifiers.




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List of equipment



23 1 Pressure regulatingvalve with filter andpressure gauge, pe =0 - 1 bar

11 1 5/2 directional controlimpulse valve


06 1 3/2 directional controlvalves with push-

button, closed neutralposition

25 2 Reflex nozzles26 2 3/2 amplifiers

Air service unit,pressure distributorand accessories (notincluded in circuitdiagram)


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Task

"Conveying parts from a drop magazine"

- After actuating the start button (S0), the piston of a double-acting cylinder pushes parts

from a drop magazine on to a conveyer belt.

- When the piston has pushed the part out of the drop magazine, it automatically

retracts.

- Additionally: a new start may only be possible if the piston of the cylinder is actually in

its back end position.

- Additionally: mechanically operated signallers cannot be used for scanning cylinder

plungers and parts. The signallers must operate "without contact".

- The working speed of the cylinder should be infinitely adjustable in both directions.

- Design the functional diagram with actuator and drive element.


or RP 68 P.


- If the start button (S0) is actuated and the reflex nozzle (B1) mounted in the back end

position of the cylinder (Z1) scans the plunger and switches the pneumatic amplifier

assigned to it, then the piston rod extends.

- The piston rod then retracts when the reflex nozzle (B2) mounted in the front end

position of the cylinder switches the assigned pneumatic amplifier and a signal reaches

the control port 12 of the impulse valve.

- The speed of both cylinder movements can be infinitely adjusted with the flow control

valves with non-return.

Didactic notes

- Discuss applications with proximity switching pneumatic signalling technology in

pneumatics such as areas where there is a danger of explosion, situations where there

is a danger of dust and contamination.

- Explain the function of reflex nozzles.

- Explain the operation principle of pneumatic amplifiers (flapper-nozzle principle).- State the proper working pressure of nozzles and amplifiers.


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Instructions


arrangement sketch.

- Check and see if there is a distance of 2-3 mm set between the cylinder plunger and

the two reflex nozzles.


accessories.

- Attention: check whether the standard pressure and the low pressure lines on both

pressure amplifiers are properly connected.

- The pressure on the low pressure regulator should be set at pe = 0.4 bar


- The circuit is to be tested.

Conclusion

Reflex nozzlesare used in pneumatic controls for proximity switching. These signallers

work out of physical reasons in the low pressure rangeat approx. 0.3 - 0.5 bar. Therefore

the output signal X of a reflex nozzle is also a low pressure signaland must be amplified

before using in a standard pressure range.


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Exercise 12 Stop control, double-acting cylinder with 5/3 directional control

valve, tensile load

Aim

This exercise demonstrates the use of a 5/3 directional control valve with closed mid-

position for stopping a double-acting cylinder.

The exercise also shows the effects of leaks in the connecting lines and in the 5/3

directional control valve when holding a load.




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List of equipment Pneumatic circu it diagram

Pos. Qty. Description05 1 Double-acting cylinder,

with a device fortensile load

12 1 5/3 directional control

valve, closed mid-position


21 2 Pressure gauges06 1 3/2 directional control

valve, with pushbutton, closed neutralposition

07 1 3/2 directional controlvalve, with pushbutton, flow in both

directions (closedneutral position)

Air service unit,pressure distributorand accessories (notincluded in the circuitdiagram)

Task

"Controlling the door of a hardening plant"- The piston of the double-acting cylinder (Z1) opens and closes the doors of a

hardening plant. The push-button (S1) is to be used to open the door, and the push-

buttons (S2) to dose it again.

- As soon as one of the push-buttons is no longer actuated, the cylinder stops. The door

then remains in this position.

- In jog mode, the door can be brought into any position and locked (stopped) there.

- The active pressure is controlled by means of 2 pressure gauges at the cylinder ports.


- Design the functional diagram with actuator and drive element.


or RP 68 P.


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- The actuator, a pneumatically operated 5/3 directional control valve with closed mid-

position, is used to control a double-acting cylinder.

- The two signalling elements, S1 and S2 (two 3/2 directional control valves, manually

operated) are used to direct the piston of the cylinder upwards or downwards.

- As soon as one of the two signalling elements is actuated, the 5/3 directional control

valve moves into the closed mid-position, stopping the cylinder (locked).

- The weight of the door and with it the special stopping behavior of the cylinder is

replaced by the tensile load.

Didactic notes

- All tube connections from the actuator to the drive element must be checked for leaks.

- Refer to the result of tubes coming loose in the working lines of the cylinder.

- Point out the locking of the piston, even when there is no working pressure.- Demonstrate what happens when both signalling elements are actuated.

- How precise is the stopping with this control?

- Does the speed regulation have an effect on the precision of the stopping?

- When observing the pressure of the lower cylinder port, pull the piston down lower with

your hand.

- Clearly define the difference between stopping (locking) and positioning.

- Discuss other possible circuits for stop control (application of non-return valves in the

working lines of the cylinder).

- At the end of the exercise refer to the two other 5/3 directional control valves, (5/3

vented mid-position and 5/3 directional control valves, pressurized, mid-position).

lnstructions


arrangement sketch.

- The cylinder must be securely mounted with the tensile load (only possible with a

vertically mounted working plate).

- The components are to be piped according to the circuit diagram with plastic tubes andaccessories.

- After turning on the working pressure, the position of the cylinder, extended in neutral

position, with the tensile load is not allowed to change.

- Actuating the signalling element S2 causes the piston rod of the cylinder to move

upwards with the weight.


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- After releasing the signalling element S2, the cylinder piston stops but is still "pulled

down" a short distance by the weight.

- At this moment (working pressure of pe = 5 bar) the pressure in the upper cylinder

chamber is below patm, the pressure in the lower cylinder chamber is briefly at approx. 4

bar, but it will surely sink lower.

- Any leaks in the piping and in the elements cause the pressure to sink lower and at a

pressure of about pe = 1 bar at the piston rod side the cylinder piston continues to

move downward step by step.

Conclusion

5/3 directional control valveswith closed mid-positionare used for simple pneumatic

stop control circuits. These valves are mainly pneumatically operated, if there is no

control pressure at 14 or 12, then the valve is automatically set in the mid-position by a

spring balancing.


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Exercise 13 Pressure-dependent control of 1 double-acting cyl inder

Aim

By using a 3/2 directional control valve with adjustable minimum pressure of response, a

pressure-dependent (and in addition displacement-dependent) control of a double-acting

cylinder is put into effect.




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List of equipment Pneumatic circu it diagram


11 1 5/2 impulse valve

15 2 Flow control valves

with non-return,adjustable21 1 Pressure gauge06 1 3/2 directional control


14 2 3/2 directional controlvalves, with feeler roll

22 1 3/2 directional controlvalve, with adjustableoperating pressureAir service unit,

pressure distributorand accessories (notincluded in the circuitdiagram)

Task

"Knuckle-joint embossing press"

- The piston of a double-acting cylinder (Z1) extends and embosses a piece of metal

with the aid of a knuckle-joint embossing die.

- The piston of the cylinder retracts automatically when the embossing die has reached

the workpiece and the piece of metal has been embossed with a certain adjustable

force (pressure an the cylinder, bottom side).

- Additionally: a new start should only then be possible when the cylinder is actually in its

back end position.

- The working speed of the cylinder should be able to be infinitely adjusted in both

directions.

- Design of the functional diagram with actuator and drive element.


or RP 68 P.


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- After actuating the signalling element S0 and under the prerequisite that the limit switch

S1 has been actuated, a signal reaches the control port 14 of the 5/2 impulse valve.

The piston of the cylinder Z1 extends.

- In its front end position the piston actuates the limit switch S2.

- When the pressure exceeds the value of 4.5 bar in the back cylinder chamber of Z1

and thus in the control line 12 of the pressure-dependent 3/2 directional control valve

S5, the signalling element S5 switches.

- The output signal of S5 applies pressure to the control port 12 of the impulse valve.

- The piston of the cylinder retracts, actuates S1 in the back end position and now the

control is ready for a new start.

Didactic notes

- The adjustable pressure-dependent 3/2 directional control valve is also called a(pressure) delivery valve.

- The adjustable pressure-dependent 3/2 directional control valve can also be mounted

in a screw joint, which is directly screwed into the cylinder thread (similar to a flow

control valve with non-return).

- In order to avoid mix-ups, the topic of proportional pressure regulators should be

discussed in this context during this exercise.

- The pressure characterization on the pressure gauge should be observed at different

speeds of the piston.

Instructions


arrangement sketch.


accessories.

- The set screw on the pressure-dependent 3/2 directional control valve is to be set

counter-clockwise all the way to the left (this should result in an operating pressure of

approx. 2 bar).- The working pressure is to be turned on.

- The signalling element S0 is to be actuated.


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- The pressure on the pressure gauge should be observed and adjusted through several

attempts with the set screw at the pressure-dependent 3/2 directional control valve so

that the piston of the cylinder first retracts when the pressure has reached approx. 4.5

bar.

- The piston of the cylinder may only retract when the limit switch S2 has been actuated.

Conclusion

Pressure-dependent signalling elements in pneumatic controls are 3/2 directional control

valves with adjustable response pressure. Pressure-dependent signalling elements

(directional control valves) can be recognized by the adjusting arrowin the symbol that is

drawn through the middle of the restoring spring.


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Exercise 14 Time-dependent control of 1 double-acting cylinder

Aim

This exercise provides information on time elements used in pneumatic control technology,

their function and application.


Example of application Functional diagram (stroke-time diagram)


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List of equipment Pneumatic circui t diagram


11 1 5/2 impulse valve

15 2 Flow control valves

with non-return,adjustable06 1 3/2 directional control



9 1 3/2 directional controlvalve, pneumaticallyoperated

17 1 3/2 directional controltime-delay valve,

adjustable from 0.15 -55 sAir service unit,pressure distributorand accessories (notincluded in the circuitdiagram)

Task

"Press-in and bonding device"

- A loudspeaker membrane and a casing brushed with glue are placed into a heated

device by hand.

- After pressing the start button (S0), the piston of a double-acting cylinder (Z1) extends

and presses the membrane into the casing for a certain adjustable period of time.

- After the delay time has elapsed, the piston of the cylinder retracts automatically into its

back end position.

- Note: the time can be set between 2 and 5 seconds and has to correspond to the

period that the parts are actually being pressed together.

- Additionally: The delay time should not be influenced by the continuous actuation of the

start button (S0).

- Additionally: Even if the start button (S0) is continuously actuated, the piston of the

cylinder (Z1) should still only extend once.

- The working speed of the cylinder should be infinitely adjustable when extending.

- Design the functional diagram (stroke-time diagram) with actuator and drive element.


or RP 68 P.


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- When the signalling element S0 is actuated, the pneumatic signal is sent via the (not

yet switched) pneumatically operated 3/2 directional control valve in open neutral

position, via the limit switch S1 to the control line 14 of the 5/2 impulse valve.

- The piston of the cylinder Z1 extends and in its front end position actuates the limit

switch S2.

- When S2 is actuated, control air reaches inlet X (Z) of the 3/2 directional control delay

valve unit.

- The pressure reaches the control inlet of the air-actuated 3/2 directional control valve

via the built-in flow control valve and to the volume.

- The air coming in through the flow control valve requires some time to fill the volume.

- If the pressure at the control inlet 12 of the directional control valve in the unit reaches

the control pressure of the valve, the 3/2 directional control valve opens. The outlet 2 of

the 3/2 directional control delay valve applies pressure to the control line 12 of the 5/2impulse valve.

- The piston of the cylinder is delayed in retracting.

- Additionally: if the button S0 is actuated for a longer period, the pneumatically operated

3/2 directional control valve, pos. 9, switches after a short delay (filling the volume via

the flow control valve).

- The directional control valve interrupts the signal to S1 and the control inlet 14 of the

impulse valve.

- The control system can only be started again if the button S0 is released and then

actuated again.

Didactic notes

- In this exercise the two time functions existing in pneumatic control technology are

applied.

- The module pos. 17 is connected in closed neutral position, and the function "time

element with operating lag" results. Signal pressure results at port 2 only after the time

delay has elapsed.

- The second time element is made up of a pneumatically operated 3/2 directionalcontrol valve pos. 9, a one-way flow control valve and a plastic tube with a length of

approx. 500 mm.

This directional control valve is connected in open neutral position. This time element is

also switched in the function "with operating lag", but in this case the signal at port 2 of

the directional control valve is switched off after the time has elapsed.


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- The piping between the flow control valve with non-return and the control port of the 3/2

directional control valve pos. 9 must be absolutely leak-proof.

Instructions


arrangement sketch.


accessories.

- Instead of the volume between the one-way flow control valve pos. 15 and port 12 of

the 3/2 directional control valve pos. 9, a tube of approx. 500 mm length is used.

- The throttle of the one-way flow control valve pos. 15 is to be screwed in nearly all the

way.

- The working pressure is to be switched on.

- The signalling element S0 is to be actuated. Check whether an impulse of approx. 0.5 sat port 14 of the impulse valve (open tube) is present.

- The time delay between actuating the limit switch S2 and the beginning of retraction of

the piston should be set at approx. 4 s.

- The signalling element S0 should be actuated for a longer period of time and held: the

piston of the cylinder extends to the front end position, retracts after the time delay of

the time element pos. 17 has elapsed. The piston may not extend again despite the

actuated signaller S0.

Conclusion

Time elements in pneumatics are modulesand always consist of: 3/2 directional control

valves, flow control valves with non-returnand volumes(reservoirs). By adjusting the

throttle, the time delay (operating or release lag) is set. The length and precision of the

time delay depends on the volume sizeand on the response pressureand the type of

switchingof the directional control valve used.


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Exercise 15 Logical control with shuttle and twin-pressure valves

Aim

This exercise uses a logical control to demonstrate the use of the logic basic functions OR

(shuttle valve) or AND (two-pressure valve) in pneumatics. In this exercise, a proximity

switching signalling element (reflex nozzle) is also used.


List of equipment Example of application


04 1 Double-acting cylinder11 1 5/2 impulse valve

15 2 2 Flow control valves with non-return, adjustable

06 1 3/2 directional controlvalve, with push button, closedneutral position

13 2 3/2 directional control valves,with roller

08 1 5/2 directional control valve,manually operated

07 1 3/2 directional control valve, withpush button, flow in bothdirections (closed neutral

position)18 1 Shuttle valve, OR19 2 Twin-pressure valves, AND24 1 Pressure control valve with filter

and pressure gauge, 0 - 1 bar25 1 Reflex nozzle26 1 Amplifier, pneumatic20 1 Pressure display, pneum.

Air service unit, pressuredistributor and accessories (notincluded in the circuit diagram)


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Single and multi ple OR or AND circui ts wi th shut tle and twin pressure valves



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Task

"Logical control"

- The piston of the double-acting cylinder (Z1) of a supply station supplies workpieces

under the following logical conditions:

The start button (S0) or an auxiliary button (S1) is actuated and parts are available in

the workpiece magazine (B2).

- An optical display shows whether there are still enough parts available in the workpiece

magazine.

- The cylinder should only retract into its back end position if it has actually reached the

front end position and an acknowledgement button (S4) is actuated.

- A 5/2 impulse valve is used as an actuator.

- Additionally: for scanning work-pieces in the magazine (B2) it is not possible to use a

mechanically operated signaller.

The scanning should therefore occur in a "non-contact" manner through a reflexnozzle.

- For economic reasons (for example there are several manually operated 5/2 directional

control valves) a 5/2 directional control valve is used as a signalling element instead of

the auxiliary button (S1).



or RP 68 P.


- Signal pressure then reaches the control line 14 of the actuating drive (piston extends)

if the following conditions prove true:

the button S0 OR the button S1 is actuated, AND the reflex nozzle B2 (amplifier pos.

26) has switched.

- Signal pressure then reaches the control line 12 (piston retracts) of the actuating drive

if the limit switch S3 AND the button S4 are actuated.

- The reflex nozzle is supplied with low pressure of 0.4 bar via the pressure regulating

valve with filter pos. 24.- The pneumatic pressure display indicates whether the reflex nozzle or the amplifier is

supplying a signal.


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Didactic notes

- Demonstrate how the pressure stream of the reflex nozzle can "disturb" any object at 2

to 3 mm distance (for example a workpiece).

- The use of 5/2 directional control valves in the function of a 3/2 directional control valve

(mounting a blanking plug in port 12) is a frequent occurrence in practice dealing with

valve carrier systems. Also if it is best to use as few types of valves as possible out of

logistic and service reasons.

- Introduce the various AND cases of use of serial connection of signalling elements or

twin pressure valves.

- Compare the AND circuit with an air-operated 3/2 directional control valve and the

technical solution twin pressure valve.

- To fully cover the topic "Logic in Pneumatics" you should also talk about the equivalent

circuit for the NOT function (air-operated 3/2 directional control valve, open neutral

position).

Instructions


arrangement sketch.


accessories.

- The low pressure regulator is to be adjusted.

- The working pressure is to be turned on.

- The logic functions are to be tested.

Conclusion

The shuttle valve is available for the logical OR operation in the pneumatic system

control technology.

A twin pressure valve is used for the logical AND operation. A "serial connection" of

pneumatic signallers also results in anANDfunction.


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Exercise 16 Sequential control of 2 double-acting cylinders without

overlapping signals

Aim

This exercise helps to understand sequential controls and provides practical knowledge of

setting up and commissioning a control system with two pneumatic drives.

Practice in developing sequential diagram and pneumatic circuit diagram is exercised.


Functional diagram


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Pos. Qty. Description04 2 Double-acting cylinders

11 2 5/2 impulse valves

15 2 Flow control valves with

non-return, adjustable06 1 3/2 directional controlvalve, with push button,closed neutral position


Air service unit, pressuredistributor andaccessories (not includedin the circuit diagram)



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Task

"Transport of Workpiece"

- The workpieces coming in on the right roller conveyor should be elevated and sent in a

new direction.

- After actuating the start button (S0) the piston of cylinder 1 (Z1) raises the workpieces

to the height of the second roller conveyor with its elevating platform.

- Cylinder 1 (Z1) remains in this position until cylinder 2 (Z2) has pushed the workpieces

from the elevating platform onto the upper roller conveyor.

- When cylinder 2 (Z2) has securely pushed all the workpieces onto the upper roller

conveyor, cylinder 1 (Z1) moves down again.

- Only when cylinder 1 (Z1) has retracted into its lower end position does cylinder 2 (Z2)

also retract.

- Additionally: a new start is only possible when cylinder 2 (Z2) is actually in its back end

position.- The working speed of both cylinders should be infinitely adjustable in both directions.

- The functional diagram is to be developed with actuator and drive element.


or RP 68 P.


- Two double-acting cylinders, retracted in neutral position, are displacement-

dependently controlled by impulse valves.

- After actuating the start button S0, a control signal arrives at port 14 of the impulse

valve for cylinder Z1 via the actuated limit switch S3.

- The piston rod of cylinder Z1 extends and in its front end position actuates the limit

switch S2.

- The limit switch S2 sends a signal to the control port 14 of the impulse valve for

cylinder 2.

- The piston rod of cylinder 2 extends into the front end position and actuates the limit

switch S4.

- The limit switch S4 delivers the control signal to port 12 from the impulse valve forcylinder Z1.

- The piston of cylinder Z1 retracts and in its back end position actuates limit switch S1.

- The limit switch S1 delivers a signal to port 12 from the impulse valve for cylinder Z2,

the piston retracts to the back end position.

- The system control is in its initial position.


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Didactic notes

- Again point out that impulse valves have no defined basic position.

- If system controls do not operate right away it is advisable to shut off the limit switches

in order to check for errors systematically.

Instructions


arrangement sketch.


accessories.

- All flow control valves with non-return are to be set at approx. the mid-restriction of

piston rod speed.


- Button S0 should be actuated. Check if the sequence is correct.

Conclusion

The forced, step by step sequence of a sequential control is realized by an actuating

sequence of 3/2 directional control valves with fester rolls as limit switches. If no

signals ever simultaneously reach ports 14 and 12 of an actuator, then the control takes

place without signal overlappingand without additionaluse of material.


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Exercise 17 Sequential control of 2 double-acting cylinders with signal

overlapping, rollers with idle return

Aim

This exercise demonstrates a sequential control with two pneumatic drives. The signal

overlapping occurring during this exercise is constructively solved by use of rollers with idle

return. Practice is obtained in developing sequential diagrams and pneumatic circuit

diagrams.


Functional diagram


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15 2 Flow control valves with

non-return, adjustable06 1 3/2 directional controlvalve, with push button,closed neutral position

13 2 3/2 directional controlvalves, with rollers

14 2 3/2 directional controlvalves, with rollers withidle return

Air service unit, pressuredistributor andaccessories (not included

in the circuit diagram)



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Task

"Drilling and boring jig"

- The workpiece that is to be drilled is placed into a jig by hand.

- After actuating the start button (S0), the piston of a double-acting cylinder (Z1) clamps

the workpiece.

- When the workpiece has been clamped, the piston rod of the drilling cylinder (Z2)

extends, drills the workpiece and retracts (after completing the drilling procedure)

automatically back into its end position.

- When the piston of cylinder 2 (Z2) has returned to its upper end position, the piston of

cylinder 1 (Z1) also retracts and unclamps the workpiece.

- Note: If you detect one or more signal overlaps when developing the circuit diagram,

the solution can be found by using rollers with idle return.

- Additionally: a new start should only be possible when the cylinder actually is in its

back end position.- The working speed of the cylinder should be infinitely adjustable in both directions.

- The functional diagram is to be developed with actuators and drive elements.


or RP 68 P.


- Both double-acting cylinders are retracted in neutral position.

- After actuating the start button S0, a control signal arrives at port 14 of the impulse

valve for cylinder 1 via the actuated limit switch S1.

- The piston rod of cylinder 1 extends, before reaching the front end position it actuates

valve S2 (with rollers with idle return) briefly, and then continues to extend to the end

position. (The valve S2 with rollers with idle return is thus not actuated in the end

position!)

- The short impulse from signal S2 applies pressure to the control port 14 of the impulse

valve for cylinder 2.

- The piston rod of cylinder extends to the front end position and actuates the limit switch

S4.- The limit switch S4 transmits the control signal from the impulse valve to port 12 for

cylinder Z2.

- The piston of cylinder Z2 retracts and before reaching the front end position it actuates

the valve S3 with idle return roller briefly and then continues to extend to the end

position. (The valve S3 with idle return roller is thus not actuated in the end position!)


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- The short impulse from signal S3 applies pressure to the control port 12 of the impulse

valve for cylinder Z1, the piston retracts to its back end position.

- The control system is in its initial position.

Didactic notes

- The direction of actuation of the idle return roller valves is marked by an arrow in the

circuit diagram.

- Point out the following disadvantages of the solution with idle return roller valves:

- At high piston rod Speeds the impulses of idle return roller valves are too short. The

impulse valves do not switch anymore when long signal lines are used.

- The moment of cylinder movement is delayed because the impulse of the idle return

roller valve does not arrive in the end positions of the cylinder movements. This is

especially a problem with short strokes.

Instructions


arrangement sketch.


accessories.

- The idle return roller valves should be mounted so that the plunger of the cylinder

piston just misses actuating the roller in the end position.

- When mounting the parts, pay attention to the correct direction of actuation of the idle

return roller valves.


- The correct sequence is to be checked.

- Set the maximum piston rod speed with the flow control valves with non-return and

again check the correct sequence.

Conclusion

If signal overlapping occurs through the actuating sequence of the limit switches in a

sequential control, it is necessary to use otheror additional components(functions) inorder to eliminate these signal overlaps.

Signallers with idle return rollersare only briefly actuated, send only short impulses in

one direction. Idle return rollers are thus used to neutralize signal overlapping instead of

standard rollers.


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Exercise 18 Sequential control of 2 double-acting cylinders with signal

overlapping, change-over valve

Aim

This exercise demonstrates a sequential control with 2 pneumatic drives, with signal

overlapping.

A constructive solution with the use of a change-over valve is found.

Practical experience in developing sequential diagrams and recognizing signal overlaps is

gained, as well as in the methodical development of a pneumatic circuit diagram.





15 2 Flow control valves withnon-return, adjustable

06 1 3/2 directional controlvalve, with push button,closed neutral position

13 4 3/2 directional controlvalves, with rollers

Air service unit, pressuredistributor andaccessories (not includedin the circuit diagram)


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Functional diagram (complete)


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Task

"Press-in device"

- A bolt is to be pressed in to a work-piece. The workpiece is placed in by hand, the bolt

is laid on by hand.

- After actuating the start button (S0), the piston of a double-acting cylinder (Z1) pushes

the workpiece into a clamping fixture and clamps the workpiece.

- When the workpiece is clamped, the piston rod of the press-in cylinder (Z2) extends,

presses the bolt into the workpiece and automatically retracts to its end position.

- When the piston of cylinder 2 (Z2) returns to its upper end position, the piston of

cylinder 1 (Z1) also retracts to its end position.- The sequence of the control is displacement-dependent. Limit switches can be

mounted on both cylinders.

- Additionally: a new start should only be possible if the cylinder is actually in its

ee061 pneumatic controls pr inst

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