Pneumatic circuits.ppt

8/21/2019 Pneumatic circuits.ppt

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Basic Pneumatic Circuitry

For control and automation


2/134

Contents

Symbols

Circuit layout

Actuator control 2/2 Valve

Actuator control 3/2 Valve Actuator control 5/2 Valve

Sequence solution

5/3 Valves

Poppet/spool logic

Balanced spool logic Feedbac

Sequential control

Clic t!e section to advance directly to it

"ntroduction


3/134

"ntroduction

#!is module s!o$s t!emet!ods o% application o%

pneumatic valves and

components %or control

and automation

#!e met!ods o% purepneumatic sequential

control are con%ined to

simple e&amples

#!e ma'ority o% modern

systems are controlledelectronically and is t!e

sub'ect o% electro(

pneumatic modules

A message to pneumaticcircuit designers) *se proven and reliable

design tec!niques

Produce circuits and

documentation t!at areclear to read

+esign %or sa%ety

+o not try to be too

clever, t!e circuit $ill be

di%%icult %or ot!ers to

read and maintain


4/134

Symbols

#!e standard %or %luid po$er symbols is "S- .2.(.0 #!isis a set o% basic s!apes and rules %or t!e construction o%

%luid po$er symbols

Cylinders can be dra$n to s!o$ t!eir e&treme or

intermediate positions o% stroe and any lengt! above

t!eir $idt! Valves s!o$ all states in t!e one symbol0 #!e prevailing

state is s!o$n $it! t!e port connections

-t!er components are single state symbols


5/134

Symbols single acting actuators

Single acting, sprunginstroed

Single acting, sprung

outstroed


instroed, magnetic


outstroed, magnetic


6/134

Symbols double acting actuators

+ouble acting, non(cus!ioned

+ouble acting, ad'ustable

cus!ions

+ouble acting, t!roug!

rod, ad'ustable cus!ions

+ouble acting, magnetic,

ad'ustable cus!ions

+ouble acting, rodless,

magnetic, ad'ustablecus!ions


7/134

Symbols rotary actuators

Semi(rotary double acting 1otary motor single

direction o% rotation

1otary motor bi(

directional


8/134

Symbols valves

2/2 Valve pus! button /spring

3/2 Valve pus! button /

spring

3/2 Valve detented leveroperated

2

13

12 10

21012

1

1

2

312

10


9/134

Symbols valves

3/2 Valve di%%erentialpressure operated

5/2 Valve pus! button /

spring

5/3 Valve double pressureoperated spring centre

1

24

5 3

14 12

1

24

5 3

1

2

3

12 10


10/134

Symbols valves

A valve %unction is no$n by a pair o% numbers e0g0 3/20 #!isindicates t!e valve !as 3 main ports and 2 states

#!e valve symbol s!o$s bot! o% t!e states

Port numbering is to C#-P 1P4P and s!o$s) $!en t!e valve is operated at t!e .2 end port . is connected to port 2

$!en reset to t!e normal state at t!e . end port . is connected tonot!ing 67

2

13

12 10


11/134

Symbols valves

A valve %unction is no$n by a pair o% numbers e0g0 3/20 #!isindicates t!e valve !as 3 main ports and 2 states

#!e valve symbol s!o$s bot! o% t!e states

Port numbering is to C#-P 1P4P and s!o$s) $!en t!e valve is operated at t!e .2 end port . is connected to port 2

$!en reset to t!e normal state at t!e . end port . is connected tonot!ing 67

2

13

12 10


12/134

Symbols valves

#!is e&ample is %or a 5/2valve

#!is !as 5 main ports and

2 states

8!en t!e valve is

operated at t!e .9 endport . is connected to port

9 6also port 2 is connected

to port 37

8!en reset to t!e normal

state at t!e .2 end port .is connected to port 2

6also port 9 is connected

to port 57

1

24

5 3

14 12


13/134

Symbols valves

#!is e&ample is %or a 5/2valve

#!is !as 5 main ports and

2 states

8!en t!e valve is

operated at t!e .9 endport . is connected to port

9 6also port 2 is connected

to port 37

8!en reset to t!e normal

state at t!e .2 end port .is connected to port 2

6also port 9 is connected

to port 57

1

24

5 3

14 12


14/134

Symbols operators manual

:eneral manual

Pus! button

Pull button

Pus!/pull button

;ever

Pedal

#readle

1otary nob


15/134

Symbols operators mec!anical

Plunger

Spring normallyas a return

1oller

*ni(direction

or one $ay trip

Pressure

Pilot pressure

+i%%erential pressure

+etent in 3 positions


16/134

Symbols 5/3 valves

All valves types s!o$n in t!e normal position

#ype .0 All ports bloced

#ype 20 -utlets to e&!aust

#ype 30 Supply to outlets


17/134

Symbols %unction components

Silencer

?uic e&!aust valve $it!

silencer

Pressure to electric

s$itc! ad'ustable

@


18/134

Symbols air line equipment

8ater separator $it!automatic drain

Filter $it! manual drain

Filter $it! automatic drain

Filter $it! automatic drain

and service indicator

;ubricator

Pressure regulator $it!

gauge

F010;0 %ilter, regulator,

lubricator simpli%ied

symbol


19/134

Circuit layout

#!e standard %or circuitdiagrams is "S- .2.(2

A9 %ormat or A3 %olded to

A9 !eig!t %or inclusion in

a manual $it! ot!er A9

documentation #o be on several s!eets i%

necessary $it! line

identi%ication code

inimum crossing lines

;imit valves position o%operation by actuators

s!o$n by a marer $it!

re%erence code to symbol

Circuits s!ould be dra$n

$it! all actuators at t!e

top o% t!e page in order o%

sequential operation

-t!er components to be

dra$n in sequential order

%rom t!e bottom up and

%rom le%t to rig!t

Circuit s!ould s!o$ t!e

system $it! pressure

applied and ready to start


20/134

Component identi%ication

#!e "S- suggestedcomponent numbering

system is suited %or large

circuits and t!ose dra$n

on several pages

For t!is presentation asimple code is used

For cylinders) A,B,C etc0

For associated %eedbac

valves) alp!a(numeric

code =a> %or proo% o%instroe, =a.> %or proo% o%

outstroe

For cylinder B) b and b.

A

a0 a1

1

2

3

12 10

a0

2

13

12 10

a1


21/134

&ample circuit

1un/nd

A

a0 a1

B

b0 b1

C

c0 c1

a0 a1 b0b1 c0c1

. bar ma& bar #o all inlet ports mared

Sequence

1un/nd

A

BB(

C

C(

A(

1epeat


22/134

Actuator control 2/2 valve


23/134

2/2 Valve actuator control

A pair o% t!e most basico% all valve types t!e 2/2

can be used to control a

single acting cylinder

#!e normally closed

position o% t!e valve isproduced by t!e spring

#!e operated position is

produced by t!e pus!

button

-ne valve admits air t!eot!er valve e&!austs it

21012

1

11012

2-*# "<


24/134


#!e button mared -*#is pus!ed to operate t!e

valve

Air is connected to t!e

cylinder and it outstroes

Air cannot escape toatmosp!ere t!roug! t!e

valve mared "< as t!is is

closed

#!e air at atmosp!eric

pressure in t!e %ront o%t!e cylinder vents

t!roug! t!e breat!er port

210

1

1211012

2-*# "<


25/134


#!e pus! button o% t!evalve mared -*# is

released and it returns to

a normal closed position

Air is no$ trapped in t!e

system and providedt!ere are no leas t!e

piston rod $ill stay in t!e

outstroed position

"% t!e load increases

beyond t!e %orce e&ertedby t!e air t!e piston rod

$ill start to move in

210

1

1211012

2-*# "<


26/134


#!e button mared "< ispus!ed to operate t!e

valve

Air escapes and t!e

piston rod moves to t!e

instroed position #!e pus! button must be

!eld operated until t!e

piston rod is %ully in

Atmosp!eric air $ill be

dra$n in to t!e %ront o%t!e cylinder t!roug! t!e

vent port

210

1

121

2

1012

-*# "<


27/134


"% t!e button mared "< isreleased t!e piston rod

$ill remain in t!e

instroed position

Any leas in t!e

installation can cause t!episton rod to creep

210

1

121

2

1012

-*# "<


28/134


#o control t!e speed o%t!e piston rod, %lo$

restrictors are placed in

t!e pipes close to eac! o%

t!e valves0

Ad'ustment o% t!erestrictors $ill slo$ do$n

t!e %lo$ rate t!ereby

giving independent

outstroe and instroe

speed control

1012 1012

-*# "<

2

1

1

2


29/134


By repeated operation o%eit!er button during

movement t!e piston rod

can be moved in small

steps %or appro&imate

positioning #!is $ill only be

success%ul under slo$

speeds1012 1012

-*# "<

2

1

1

2


30/134


8it! any compressed airsystem t!at intentionally

traps air, t!e potential

!aard o% t!is must be

recognised

*nintended release orapplication o% pressure

can give rise to

une&pected movement o%

t!e piston rod

A pressure indicator orgauge must be %itted to

$arn o% t!e presence o%

pressure

210

1

121

2

1012

-*# "<


31/134



32/134

3/2 valve actuator control

A 3 port valve provides t!einlet and e&!aust pat! and

is t!e normal c!oice %or

t!e control o% a single

acting cylinder

"n t!e normal positionproduced by t!e spring,

t!e valve is closed

"n t!e operated position


button t!e valve is open #!e pus! button must be

!eld do$n %or as long as

t!e cylinder is outstroed

1

2

3

12 10


33/134





acting cylinder


t!e valve is closed






1

2

3

12 10


34/134





acting cylinder


t!e valve is closed






1

2

3

12 10


35/134


#o generally slo$ t!ecylinder speed an

ad'ustable

bi(directional %lo$

regulator or %i&ed

restrictor can be used #!e %lo$ regulator

setting $ill be a

compromise as t!e ideal

outstroe speed may not

produce t!e desiredresults %or t!e instroe

speed

1

2

3

12 10


36/134


#o control t!e outstroespeed o% a single acting

cylinder $it!out

controlling t!e instroe

speed, a uni(directional

%lo$ regulator is used #!e %lo$ into t!e cylinder

closes t!e non return

valve and can only pass

t!roug! t!e ad'ustable

restrictor By ad'usting t!e restrictor

t!e outstroe speed o% t!e

cylinder can be set

1

2

3

12 10


37/134


For independent speedcontrol in eac! direction

t$o %lo$ regulators are

required

"nstalled in opposite

directions to eac! ot!er *pper regulator controls

t!e outstroe speed

;o$er regulator controls

t!e instroing speed 1

2

3

12 10


38/134





acting cylinder


t!e valve is closed






1

2

3

12 10


39/134



40/134


For a double acting cylindert!e po$er and e&!aust

pat!s are s$itc!ed

simultaneously

8!en t!e button is pus!ed

t!e supply at port . is

connected to port 9 and t!e

outlet port 2 connected to

e&!aust port 30 #!e cylinder

moves plus

8!en t!e button is released

port . is connected to port 2and port 9 connected to

port 50 Cylinder minus

1

24

5 3

14 12

(


41/134


For a double acting cylindert!e po$er and e&!aust

pat!s are s$itc!ed

simultaneously

8!en t!e button is pus!ed

t!e supply at port . is

connected to port 9 and t!e

outlet port 2 connected to

e&!aust port 30 #!e cylinder

moves plus

8!en t!e button is released

port . is connected to port 2and port 9 connected to

port 50 Cylinder minus

1

24

5 3

14 12

(


42/134


"ndependent speedcontrol o% t!e plus and

minus movements

"n most applications

speed is controlled by

restricting air out o% acylinder

Full po$er is developed

to drive t!e piston $it!

speed controlled by

restricting t!e bacpressure

1

24

5 3

14 12

(


43/134


"ndependent speedcontrol o% t!e plus and

minus movements

"n most applications

speed is controlled by

restricting air out o% acylinder

Full po$er is developed

to drive t!e piston $it!

speed controlled by

restricting t!e bacpressure

1

24

5 3

14 12

(


44/134


Valves $it! a spring returnare mono(stable and need

t!e operator to be !eld all

t!e time t!at t!e cylinder is

required in t!e plus position

Bi(stable valves $ill stay in

t!e position t!ey $ere last

set

#!e lever valve e&ample

illustrated indicates a

detent mec!anism0 #!e

lever need not be !eld oncet!e ne$ position !as been

establis!ed

1

24

5 3

14 12

(


45/134

anual control

1emote manual control o%a double acting cylinder

Valve mared $ill cause

t!e cylinder to outstroe

or move plus

Valve mared ( $ill causet!e cylinder to instroe or

move minus

#!e 5/2 double pilot valve

is bi(stable t!ere%ore t!e

pus! button valves onlyneed to be pulsed

1

24

5 3

14 12

1

2

3

12 10

1

2

3

12 10

(

(


46/134

anual control




or move plus


move minus




1

24

5 3

1

2

3

12 10

1

2

3

12 10

14 12

(

(


47/134

anual control




or move plus


move minus




1

24

5 3

1

2

3

12 10

1

2

3

12 10

14 12

(

(


48/134

anual control




or move plus


move minus




1

24

5 3

14 12

1

2

3

12 10

1

2

3

12 10

(

(


49/134

anual control




or move plus


move minus




1

24

5 3

14 12

1

2

3

12 10

1

2

3

12 10

(

(


50/134

Semi(automatic control

anual remote start o% adouble acting cylinder

$it! automatic return

Cylinder identi%ied as DAE

#rip valve operated at t!e

completion o% t!e plusstroe identi%ied as Da.E

1

24

5 3

14 12

1

2

3

12 10

1

2

3

12 10

(

(

A

a1

a1


51/134

Fully(automatic control

Continuous automaticcycling %rom roller

operated trip valves

anual 1un and nd o%

t!e automatic cycling

Cylinder $ill come to restin t!e instroed position

regardless o% $!en t!e

valve is put to nd

#ags %or t!e roller

%eedbac valves a anda. s!o$ t!eir relative

positions

1

24

5 3

14 12

2

13

12 10

1

2

3

12 10

1

2

312

10

Run/End

(

A

a0 a1

a0 a1


52/134

Sequential control


53/134

Circuit building blocs

#!ese circuits can be considered as building blocs %or

larger sequential circuits consisting o% t$o or more cylinders

ac! actuator $ill !ave a po$er valve and t$o associated

%eedbac valves0 #!e %irst actuator to move also !as

a 1un/nd valve

1un/nd

A B

a0 a1 b0 b1


54/134

1epeat pattern sequence

A repeat patternsequence is one $!ere

t!e order o% t!e

movements in t!e %irst

!al% o% t!e sequence is

repeated in t!e second!al%

ac! actuator may !ave

one -ut and "n stroe

only in t!e sequence

#!ere may be any numbero% actuators in t!e

sequence

#!e signal starting t!e%irst movement must pass

t!roug! t!e 1un/nd

valve


55/134


#!e t$o cylinders A and B are to per%orm a simple repeat pattern

sequence as %ollo$s) A B A( B(

Apply t!e rule D#!e signal given by t!e completion o% eac! movement $ill

initiate t!e ne&t movementE

"n t!is $ay t!e roller valves can be

identi%ied and labelled

1un/nd

A B

a0a1b0 b1

a0 a1 b0 b1


56/134


For t!ree cylinders A, B and C also to per%orm a simple

repeat pattern sequence as %ollo$s) A B C A( B( C( Apply t!e rule D#!e signal given by t!e completion o% eac!

movement $ill initiate t!e ne&t movementE

1un/nd

A

c0 c1

a0 a1

B

a0a1

b0 b1

C

b0b1

c0 c1


57/134


58/134

-pposed signals

8!en t!e valve is set to 1un, cylinder A $ill not move because t!e

5/2 valve !as an opposed signal, it is still being signalled to !old

position by t!e %eedbac valve b

"% A $as able to move a similar problem $ill occur %or t!e 5/2 valve

o% B once it $as

#!e sequence is A B B( A(

1un/nd

A B

b1a1a0 b0

a0 a1 b0 b1


59/134

ec!anical solution

#!e problem $as caused by valves b and a. being

operated at t!e time t!e ne$ opposing instruction is given "% t!ese t$o valves $ere Done $ay tripE types and over

tripped at t!e last movement o% stroe, only a pulse $ould

be obtained instead o% a continuous signal

1un/nd

A B

b1a1a0

a0 a1 b0 b1

b0


60/134

Sequence solution met!ods

#!e main solutions tosolving sequences are) Cascade 6pneumatic7

S!i%t register 6pneumatic7

lectro(pneumatic

P;C 6Programmablelogic controller7

Cascade circuits provide a

standard met!od o%

solving any sequence0 "t

uses a minimum o%

additional logic !ard$are

6one logic valve per group

o% sequential steps7

S!i%t register circuits aresimilar to cascade but use

one logic valve %or every

step

lectro(pneumatic circuits

use solenoid valves andelectro(mec!anical relays

P;C0 #!e standard

solution %or medium to

comple& sequential

systems 6e&cept $!ereelectrical equipment

cannot be used7


61/134

Cascade t$o group

#!e A B B( A( circuit issolved by t!e t$o group

cascade met!od

#!e sequence is divided at

t!e point $!ere B

immediately returns #!e t$o parts are

allocated groups l and ll

:p l A B / :p ll B( A(

#$o signal supplies are

provided %rom a 5/2 valveone is available only in

group l t!e ot!er is

available only in group ll

Because only one groupoutput is available at a

time it is not possible to

!ave opposed signals

A standard 5/2 double

pressure operated valveis t!e cascade valve

1

24

5 3

14 12

Group l Group ll

Select l Select ll


62/134

Cascade 6t$o group7

A B

a1

b0

a0 a1 b0 b1

1un/nd

a0 b1

Sequence

:p l A B :p ll B( A(

:p l

:p ll


63/134

Cascade 6t$o group7

A B

a1

b0

a0 a1 b0 b1

1un/nd

a0 b1

Sequence


:p l

:p ll


64/134

Cascade 6t$o group7

A B

b0

a0 a1 b0 b1

1un/nd

a1

a0 b1

Sequence


:p l

:p ll


65/134

Cascade 6t$o group7

A B

b0

a0 a1 b0 b1

1un/nd

a1

a0 b1

Sequence


:p l

:p ll


66/134

Cascade 6t$o group7

A B

a0 a1 b0 b1

1un/nd

a1

a0

Sequence


:p l

:p ll

b0

b1


67/134

Cascade 6t$o group7

A B

a0 a1 b0 b1

1un/nd

Sequence


:p l

:p ll

b0

b1

a1

a0


68/134

Cascade building blocs

A t$o group buildingbloc consists o% a lever

valve to run and end t!e

sequence plus t!e 5/2

double pilot operated

cascade valve

For a t$o group system

consisting o% any number

o% cylinders t!is building

bloc and t!e cylinder

building blocs are all

t!at is required to solve

t!e sequence

1

24

5 3

14 12

1

2

312

10

:p l

:p ll

Sel l

Sel ll1un/nd


69/134

Cascade building blocs

:p l

:p ll

Sel lSel ll

:p lll

Sel lll

1un/nd

#!is t!ree groupbuilding bloc

establis!es an

interconnecting

pattern t!at can

be e&tended to

any number o%

groups


70/134

+ual trip building blocs

8!en a sequence !as acylinder operating t$ice in

one overall sequence a

dual trip building bloc

may be required %or eac!

o% t!e t$o %eedbac valves

#!e supply $ill be %rom

di%%erent groups and t!e

output go to di%%erent

destinations

&ample is %or %eedbac

valve a. o% cylinder A

$!en A is sent bot! in

:roup & and :roup y

Send A

A in

:roup &A in

:roup y

a.

a. in &

a. in y


71/134

Cascade rules

stablis! t!e correctsequence

+ivide t!e sequence in to

groups0 Al$ays start a

sequence $it! t!e

1un/nd valve selecting

group l e0g0

1/ | A B | B( C | C( A(

Select t!e cylinder

building blocs

Select t!e cascade

building bloc

Select dual trip building

blocs i% required

"nterconnect t!e blocs as

%ollo$s)

#!e %irst %unction in eac! group

is signalled directly by t!at

group supply

#!e last trip valve operated in

eac! group is supplied $it!

main supply air and selects t!e

ne&t group

#!e remaining trip valves are

supplied $it! air %rom t!eir

respective groups and initiate

t!e ne&t %unction

#!e Drun/endE valve $ill controlt!e signal %rom t!e last trip valve

to be operated


72/134

#!ree position valves


73/134

5/3 Valve

5/3 valves !ave a t!ird midposition

#!e valve can be tri(stable

e0g0 a detented lever

operator or mono(stable

e0g0 a double air or doublesolenoid $it! spring

centre

#!ere are t!ree common

con%igurations %or t!e mid

position) All ports bloced

Centre open e&!aust

Centre open pressure

#!e ma'ority o%applications are actuator

positioning and sa%ety

24

15 3

14 12

14 1224

15 3

14 1224

15 3


74/134


#!e valve illustrated !asDall ports blocedE in t!e

mid position

8!enever t!e mid

position is selected t!e

pressure conditions in t!ecylinder $ill be %roen

#!is can be used to stop

t!e piston at part stroe in

some positioning

applications

Flo$ regulators mounted

close to t!e cylinder to

minimise creep

24

15 314 12


75/134



mid position

8!enever t!e mid


pressure conditions in t!e

cylinder $ill be %roen



some positioning

applications



minimise creep

24

15 314 12


76/134



mid position

8!enever t!e mid






some positioning

applications



minimise creep

24

15 314 12


77/134



mid position

8!enever t!e mid






some positioning

applications



minimise creep

24

15 314 12


78/134



mid position

8!enever t!e mid






some positioning

applications



minimise creep

24

15 314 12


79/134


#!is version o% a 5/3 valveis Dcentre open e&!austE

#!e supply at port . is

isolated and t!e cylinder

!as po$er e&!austed

$!en t!is centre position

is selected

#!e version illustrated

s!o$s a mono(stable

version double pilot

operated spring centre

#!e cylinder $ill be pre(

e&!austed $!en c!anging

%rom t!e mid position

24

15 3

14 12


80/134


#!is version o% a 5/3 valveis Dcentre open pressureE

#!e supply at port . is

connected to bot! sides

o% t!e cylinder and t!e

e&!aust ports isolated

$!en t!is centre position

is selected

Can be used to balance

pressures in positioning

applications

#!e version illustrated is

mono(stable, double

solenoid, spring centre

1

24

5 3

14 12


81/134

;ogic %unctions %or poppet and

spool valves


82/134

;ogic A


83/134

;ogic A


84/134

;ogic A


85/134

;ogic A


86/134

;ogic A


87/134

;ogic A


88/134

;ogic A


89/134

;ogic A


90/134

;ogic -1

*se o% an =-1> %unctions!uttle valve

Source G and H can be

remote %rom eac! ot!er

and remote %rom t!e

destination o% 8!en G or H is operated

t!e s!uttle valve seal

moves across to prevent

t!e signal %rom being

lost t!roug! t!e e&!austo% t!e ot!er valve

G

H

1

2

3

12 10

1

2

3

12 10

; i -1


91/134

;ogic -1




and remote %rom t!e





lost t!roug! t!e e&!aust

o% t!e ot!er valve

G

H

1

2

3

12 10

1

2

3

12 10

; i -1


92/134

;ogic -1




and remote %rom t!e






o% t!e ot!er valve

G

H

1

2

3

12 10

1

2

3

12 10

; i -1


93/134

;ogic -1




and remote %rom t!e






o% t!e ot!er valve

G

H

1

2

3

12 10

1

2

3

12 10

;ogic -1


94/134

;ogic -1




and remote %rom t!e






o% t!e ot!er valve

G

H

1

2

3

12 10

1

2

3

12 10

;ogic


95/134

;ogic


96/134

;ogic


97/134

;ogic


98/134

;ogic -1H

A logic -1H allo$s

t!e output signal state

6-< or -FF7 to be

maintained a%ter t!e input

signal !as been removed

Any bi(stable valve is a

logic -1H

8it! t!is lever detented

valve, once t!e lever !as

been moved G direction

or H direction it can be

released and $ill stay in

t!at position

G

1310

H

12

;ogic -1H


99/134

;ogic -1H

A logic -1H allo$s

t!e output signal state

6-< or -FF7 to be

maintained a%ter t!e

signal t!at set it !as been

removed

G13

12 10 H

;ogic -1H


100/134

;ogic -1H

A bi(stable double pilot

valve can be set or reset

simply by a pulse 6pus!

and release7 on buttons G

or H

13

G

H1

2

3

12 10

1

2

3

12 10

12 10

;ogic -1H


101/134

;ogic -1H





or H

13

G

H1

2

3

12 10

1

2

3

12 10

12 10

;ogic -1H


102/134

;ogic -1H





or H

13

G

H1

2

3

12 10

1

2

3

12 10

12 10

;ogic -1H


103/134

;ogic -1H





or H

13

G

H1

2

3

12 10

1

2

3

12 10

12 10

;ogic -1H


104/134

;ogic -1H





or H

13

G

H1

2

3

12 10

1

2

3

12 10

12 10

;ogic -1H 6latc!7


105/134

;ogic -1H 6latc!7

A popular memory circuit

is t!e latc!

8ill not re(mae a%ter

pneumatic po$er %ailure

A pulse on G operates t!e

pilot / spring valve to give

output

A %eedbac %rom runs

t!roug! t!e normally open

valve H to latc! t!e

operation o% $!en G is

released

A pulse on H breas t!e

latc! and is e&!austed

G

H

13

1

2

3

12 10

1012

3

2

1

12 10

;ogic -1H 6latc!7


106/134

;ogic -1H 6latc!7


is t!e latc!





output

A %eedbac %rom runs




released



G

H

13

1

2

3

12 10

12 10

3

2

1

12 10

;ogic -1H 6latc!7


107/134

;ogic -1H 6latc!7


is t!e latc!





output

A %eedbac %rom runs




released



G

H

13

1

2

3

12 10

12 10

3

2

1

12 10

;ogic -1H 6latc!7


108/134

;ogic -1H 6latc!7


is t!e latc!





output

A %eedbac %rom runs




released



G

H

13

1

2

3

12 10

3

2

1

12 10

12 10

;ogic -1H 6latc!7


109/134

;ogic -1H 6latc!7


is t!e latc!





output

A %eedbac %rom runs




released



G

H

13

1

2

3

12 10

3

2

1

12 10

12 10


110/134

;ogic arrangements %or %ully

balanced spool valves

;ogic circuits 6spool valves7


111/134

;ogic circuits 6spool valves7

Selection / +iversion

;atc!

-1, A


112/134

3/2


113/134

3/2


114/134

3/2 Valve selection / diversion

Selection o% one o% t$o

supplies connected to

ports . and 3 can be

di%%erent pressures

+iversion o% one supply

to one o% t$o outlets

"% it is required to e&!aust

t!e do$nstream air a 5/2

valve is required

1

2

3

12 10

2

13

12 10



115/134


Selection o% one o% t$o

supplies connected to

ports . and 3 can be

di%%erent pressures

+iversion o% one supply

to one o% t$o outlets

"% it is required to e&!aust

t!e do$nstream air a 5/2

valve is required

1

2

3

2

13

12 10

12 10

;atc! $it! controls


116/134

;atc! $it! controls

"n t!is version o% a latc!

t!e pus! button valves

are connected to per%orm

=-1> and = %unctions

#!e =-FF> valve must be

placed last in t!e signal

c!ain so t!at i% bot!

valves are operated

toget!er t!e =-FF>

command $ill dominate

over t!e =- command

1

2

3

12 10

2

13

12 10

2

13

12 10

-<

-FF

-ut

-1, A


117/134

-1, A


118/134

Single pulse maer

Converts a prolonged

signal x into a single

pulse z

Signal must be removed

to allo$ t!e valve to reset

t!en & can be applied

again

#!e duration o% t!e pulse

can be ad'usted $it! t!e

%lo$ regulator

1

2

3

12 10

x

z

Slo$ initial pressure build up


119/134

Slo$ initial pressure build up

C!oose a 3/2 pilot spring

valve $it! a relatively

!ig! operating %orce e0g0

3 to 9 bar

8!en t!e quic connect

coupling is made, t!e

output at port 2 is

controlled at t!e rate o%

t!e %lo$ regulator setting

8!en t!e pressure is

!ig! enoug! to operate

t!e valve %ull %lo$ $ill

tae over

1

2

3

12 10

Pre(select


120/134

Pre select

#!e lever valve can pre(

select t!e movement o%

t!e cylinder -*# or "<

#!e movement $ill occur

t!e ne&t time t!e plunger

valve is operated

#!e plunger valve can be

released immediately and

subsequently operated

and released any number

o% times

1

2

3

12 10

1

2

3

12 10

1

2

3

12

10

-*#/"<

pre(select

5/2 -1 %unction


121/134

5/2 -1 %unction

#!e valve at position =a> is

reversed connected and

supplied %rom t!e valve

conventionally connected

at position =b>

#!e cylinder can be

controlled %rom eit!er

position =a> =-1> position

=b>

1

24

5 3

14 12

1

24

5 3

14 12

a

b

Single pulse control


122/134

g p

24

14 12

1

2

3

12 10

15

12 10

1

2

3

2

13

1210

ac! time t!e %oot

operated valve is

pressed t!e cylinder

$ill single stroe

and ( alternately

First %oot operation

t!e cylinder moves

out

Second %oot

operation t!e

cylinder moves in

#!irdI00 out and so

on

Air conservation


123/134

Po$er stroe in t!e

instroe direction only

+i%%erential area o% t!e

piston gives an outstroe

%orce $!en t!e pressure

is balanced

Air used to outstroe is

equivalent to a cylinder

$it! only t!e same bore

as t!e rod diameter

Assumes t!e cylinder is

not loaded on t!e plus

stroe and lo$ %riction

24

15

14 12

Air conservation


124/134

Po$er stroe in t!e

instroe direction only

+i%%erential area o% t!e

piston gives an outstroe

%orce $!en t!e pressure

is balanced

Air used to outstroe is

equivalent to a cylinder

$it! only t!e same bore

as t!e rod diameter

Assumes t!e cylinder is

not loaded on t!e plus

stroe and lo$ %riction

24

15

14 12

+ouble %lo$


125/134

8!ere a larger 3/2 valve

is not available

#$o %lo$ pat!s in a 5/2

valve eac! $it! a

separate supply can be

arranged to give double

%lo$ or supply separate

devices

nsure t!e tube sie to

t!e cylinder is large

enoug! to tae t!e double

%lo$

4 2

1 3

1214

5 1

+ouble %lo$


126/134

8!ere a larger 3/2 valve

is not available

#$o %lo$ pat!s in a 5/2

valve eac! $it! a

separate supply can be

arranged to give double

%lo$ or supply separate

devices

nsure t!e tube sie to

t!e cylinder is large

enoug! to tae t!e double

%lo$

4 2

1 3

1214

5

Counting


127/134

g

Counting applications are

best ac!ieved $it! electro(mec!anical or

programmable electronic

counters

Pneumatic counting circuits

use large numbers o% logicvalves and can be slo$

#!e counting c!ain s!o$n

$ill count to 9

1ed and blue are non(

overlapping alternatepulses, purple is t!e reset

line

.

2

3

9

Counting application


128/134

g pp

#!e counting circuit is

applied to count 9 stroes o%a cylinder

At rest all counting valves

are !eld reset by t!e start

valve

Start outstroes =A> Alternate signals %rom =a.>

and =a> progresses

operation o% t!e counting

valves up t!e c!ain

-n t!e 9t! operation o% =a.>

t!e green signal resets t!e

start valve to stop t!e

cylinder

A

aa.

a a.

Start


129/134

Feedbac met!ods

#ime delay


130/134

y

A signal is restricted to

slo$ t!e rate o% pressure

build up on a pressure

s$itc! 63/2 di%%erential

pressure operated valve7

8!en t!e pressure s$itc!

operates a strong un(restricted output is given

A reservoir provides

capacitance to allo$ less

%ine and sensitive settings

on t!e %lo$ regulatormaing it easy to ad'ust

1

2

3

12 10

Signal

in

-utput

#ime delay


131/134

y

anual remote start o% a

double acting cylinder

$it! a time delay in t!e

outstroed position

be%ore automatic return

2

1

24

5 3

14 12

13

12 10

(

A

a1

1

2

3

12 10

a1

1

2

3

12 10

Pressure decay


132/134

y

anual remote start o% a

double acting cylinder

*ses a lo$ pressure

operated valve connected

normally open

8!en t!e bac pressure in

t!e %ront o% t!e cylinder%alls belo$ 0. bar t!e

return signal is given

Connection taen bet$een

t!e cylinder and %lo$

regulator *se%ul %or pressing $or

pieces o% variable sie

1

24

5 3

14 12

2

13

12 10

(

A

a1

21210

1 3 0.bar

lectro(pneumatic


133/134

#!e ma'ority o% systems

use electrical/electroniccontrol due to t!e !ig!

degree o% sop!istication

and %le&ibility

Solenoid valves are used to

control cylinders Feedbac signals are %rom

reed s$itc!es, sensors and

electrical limit s$itc!es

;ogic is !ard $ired or

programmed in to a P;C6programmable logic

controller7a a.

1

24

5 3

14 12

A

a a.

Circuit building bloc %or

eac! cylinder


134/134

nd

Pneumatic circuits.ppt

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