ความรู้พื้นฐานระบบนิวเมติก

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ความรู้พื้นฐานระบบนิวเมติก

  1. 1. Basic Pneumatic Circuitry For control and automation
  2. 2. Contents Introduction Sequential control Symbols Sequence solution Circuit layout 5/3 Valves Actuator control 2/2 Valve Poppet/spool logic Actuator control 3/2 Valve Balanced spool logic Actuator control 5/2 Valve FeedbackClick the section to advance directly to it
  3. 3. IntroductionThis module shows the A message to pneumaticmethods of application of circuit designers:pneumatic valves and Use proven and reliablecomponents for control design techniquesand automation Produce circuits andThe methods of pure documentation that arepneumatic sequential clear to readcontrol are confined to Design for safetysimple examples Do not try to be too clever, the circuit will beThe majority of modern difficult for others tosystems are controlled read and maintainelectronically and is thesubject of electro-pneumatic modules
  4. 4. SymbolsThe standard for fluid power symbols is ISO 1219-1. This isa set of basic shapes and rules for the construction offluid power symbolsCylinders can be drawn to show their extreme orintermediate positions of stroke and any length abovetheir widthValves show all states in the one symbol. The prevailingstate is shown with the port connectionsOther components are single state symbols
  5. 5. Symbols single acting actuatorsSingle acting, sprunginstrokedSingle acting, sprungoutstrokedSingle acting, sprunginstroked, magneticSingle acting, sprungoutstroked, magnetic
  6. 6. Symbols double acting actuatorsDouble acting, non-cushionedDouble acting, adjustablecushionsDouble acting, throughrod, adjustable cushionsDouble acting, magnetic,adjustable cushionsDouble acting, rodless,magnetic, adjustablecushions
  7. 7. Symbols rotary actuatorsSemi-rotary double actingRotary motor singledirection of rotationRotary motor bi-directional
  8. 8. Symbols valves 22/2 Valve push button / 12 10spring 13/2 Valve push button / 12 2 10spring 3 13/2 Valve detented lever 2 10operated 12 3 1
  9. 9. Symbols valves 23/2 Valve differential 12 10pressure operated 3 1 4 25/2 Valve push button / 14 12spring 5 1 35/3 Valve double pressure 4 2operated spring centre 5 1 3
  10. 10. Symbols valvesA valve function is known by a pair of numbers e.g. 3/2.This indicates the valve has 3 main ports and 2 statesThe valve symbol shows both of the statesPort numbering is to CETOP RP68P and shows: when the valve is operated at the 12 end port 1 is connected to port 2 when reset to the normal state at the 10 end port 1 is connected to nothing (0) 2 12 10 3 1
  11. 11. Symbols valvesA valve function is known by a pair of numbers e.g. 3/2.This indicates the valve has 3 main ports and 2 statesThe valve symbol shows both of the statesPort numbering is to CETOP RP68P and shows: when the valve is operated at the 12 end port 1 is connected to port 2 when reset to the normal state at the 10 end port 1 is connected to nothing (0) 2 12 10 3 1
  12. 12. Symbols valvesThis example is for a 5/2valveThis has 5 main ports and2 statesWhen the valve is 4 2operated at the 14 end 14 12port 1 is connected toport 4 (also port 2 is 5 1 3connected to port 3)When reset to the normalstate at the 12 end port 1is connected to port 2(also port 4 is connectedto port 5)
  13. 13. Symbols valvesThis example is for a 5/2valveThis has 5 main ports and2 statesWhen the valve is 4 2operated at the 14 end 14 12port 1 is connected toport 4 (also port 2 is 5 1 3connected to port 3)When reset to the normalstate at the 12 end port 1is connected to port 2(also port 4 is connectedto port 5)
  14. 14. Symbols operators manualGeneral manual LeverPush button PedalPull button TreadlePush/pull button Rotary knob
  15. 15. Symbols operators mechanicalPlunger PressureSpring normally Pilot pressureas a returnRoller Differential pressureUni-direction Detent in 3 positionsor one way trip
  16. 16. Symbols 5/3 valvesAll valves types shown in the normal positionType 1. All ports blockedType 2. Outlets to exhaustType 3. Supply to outlets
  17. 17. Symbols function componentsNon-return valveFlow regulator uni-directionalFlow regulator bi-directional *Two pressure ‘AND’ ISO 1219-1 OldShuttle valve ‘OR’SilencerQuick exhaust valve withsilencerPressure to electricswitch adjustable * Note: Traditional symbol in extensive use (preferred)
  18. 18. Symbols air line equipmentWater separator withautomatic drainFilter with manual drainFilter with automatic drainFilter with automatic drainand service indicatorLubricatorPressure regulator withgaugeF.R.L. filter, regulator,lubricator simplifiedsymbol
  19. 19. Circuit layoutThe standard for circuit Circuits should be drawndiagrams is ISO 1219-2 with all actuators at theA4 format or A3 folded to top of the page in order ofA4 height for inclusion in sequential operationa manual with other A4 Other components to bedocumentation drawn in sequential orderTo be on several sheets if from the bottom up andnecessary with line from left to rightidentification code Circuit should show theMinimum crossing lines system with pressureLimit valves position of applied and ready to startoperation by actuatorsshown by a marker withreference code to symbol
  20. 20. Component identificationThe ISO suggested Note: the a0 valve symbolcomponent numbering is drawn in the operatedsystem is suited for large position because thecircuits and those drawn actuator A is instrokedon several pages a0 a1For this presentation asimple code is used AFor cylinders: A,B,C etc.For associated feedbackvalves: alpha-numeric 2 2code ‘a0’ for proof of 12 10 12 10instroke, ‘a1’ for proof of a0 3 1 a1 3 1outstrokeFor cylinder B: b0 and b1
  21. 21. Example circuit a0 a1 b0 b1 c0 c1 A B C Sequence Run/End A+ B+ B- C+ C- A- RepeatRun/End a0 a1 b1 b0 c1 c010 bar max 6 bar To all inlet ports marked
  22. 22. Actuator control 2/2 valve
  23. 23. 2/2 Valve actuator controlA pair of the most basicof all valve types the 2/2can be used to control asingle acting cylinderThe normally closedposition of the valve isproduced by the spring 2 1The operated position is 12 10 12 10produced by the push 1 2button OUT INOne valve admits air theother valve exhausts it
  24. 24. 2/2 Valve actuator controlThe button marked OUTis pushed to operate thevalveAir is connected to thecylinder and it outstrokesAir cannot escape toatmosphere through the 2 1valve marked IN as this is 12 10 12 10closed 1 2The air at atmospheric OUT INpressure in the front ofthe cylinder ventsthrough the breather port
  25. 25. 2/2 Valve actuator controlThe push button of thevalve marked OUT isreleased and it returns toa normal closed positionAir is now trapped in thesystem and providedthere are no leaks thepiston rod will stay in the 2 1 12 10 12 10outstroked position 1 2If the load increases OUT INbeyond the force exertedby the air the piston rodwill start to move in
  26. 26. 2/2 Valve actuator controlThe button marked IN ispushed to operate thevalveAir escapes and thepiston rod moves to theinstroked positionThe push button must be 2 1held operated until the 12 10 12 10piston rod is fully in 1 2Atmospheric air will be OUT INdrawn in to the front ofthe cylinder through thevent port
  27. 27. 2/2 Valve actuator controlIf the button marked IN isreleased the piston rodwill remain in theinstroked positionAny leaks in theinstallation can cause thepiston rod to creep 2 1 12 10 12 10 1 2 OUT IN
  28. 28. 2/2 Valve actuator controlTo control the speed ofthe piston rod, flowrestrictors are placed inthe pipes close to each ofthe valves.Adjustment of therestrictors will slow downthe flow rate thereby 2 1 12 10 12 10giving independentoutstroke and instroke 1 2 OUT INspeed control
  29. 29. 2/2 Valve actuator controlBy repeated operation ofeither button duringmovement the piston rodcan be moved in smallsteps for approximatepositioningThis will only besuccessful under slow 2 1 12 10 12 10speeds 1 2 OUT IN
  30. 30. 2/2 Valve actuator controlWith any compressed airsystem that intentionallytraps air, the potentialhazard of this must berecognisedUnintended release orapplication of pressurecan give rise to 2 1 12 10 12 10unexpected movement ofthe piston rod 1 2 OUT INA pressure indicator orgauge must be fitted towarn of the presence ofpressure
  31. 31. Actuator control 3/2 valve
  32. 32. 3/2 valve actuator controlA 3 port valve providesthe inlet and exhaust pathand is the normal choicefor the control of a singleacting cylinderIn the normal position 2 12 10produced by the spring,the valve is closed 3 1In the operated positionproduced by the pushbutton the valve is openThe push button must beheld down for as long asthe cylinder is outstroked
  33. 33. 3/2 valve actuator controlA 3 port valve providesthe inlet and exhaust pathand is the normal choicefor the control of a singleacting cylinderIn the normal position 2 12 10produced by the spring,the valve is closed 3 1In the operated positionproduced by the pushbutton the valve is openThe push button must beheld down for as long asthe cylinder is outstroked
  34. 34. 3/2 valve actuator controlA 3 port valve providesthe inlet and exhaust pathand is the normal choicefor the control of a singleacting cylinderIn the normal position 2 12 10produced by the spring,the valve is closed 3 1In the operated positionproduced by the pushbutton the valve is openThe push button must beheld down for as long asthe cylinder is outstroked
  35. 35. 3/2 valve actuator controlTo generally slow thecylinder speed anadjustablebi-directional flowregulator or fixedrestrictor can be usedThe flow regulatorsetting will be acompromise as the ideal 12 2 10outstroke speed may notproduce the desired 3 1results for the instrokespeed
  36. 36. 3/2 valve actuator controlTo control the outstrokespeed of a single actingcylinder withoutcontrolling the instrokespeed, a uni-directionalflow regulator is usedThe flow into the cylindercloses the non returnvalve and can only pass 12 2 10through the adjustablerestrictor 3 1By adjusting the restrictorthe outstroke speed ofthe cylinder can be set
  37. 37. 3/2 valve actuator controlFor independent speedcontrol in each directiontwo flow regulators arerequiredInstalled in oppositedirections to each otherUpper regulator controlsthe outstroke speed 2Lower regulator controls 12 10the instroking speed 3 1
  38. 38. 3/2 valve actuator controlA 3 port valve providesthe inlet and exhaust pathand is the normal choicefor the control of a singleacting cylinderIn the normal positionproduced by the spring,the valve is closed 2In the operated position 12 10produced by the push 3 1button the valve is openThe push button must beheld down for as long asthe cylinder is outstroked
  39. 39. Actuator control 5/2 valve
  40. 40. 5/2 Valve actuator control - +For a double actingcylinder the power andexhaust paths areswitched simultaneouslyWhen the button ispushed the supply at port 4 2 14 121 is connected to port 4and the outlet port 2 5 1 3connected to exhaustport 3. The cylindermoves plusWhen the button isreleased port 1 isconnected to port 2 andport 4 connected to port5. Cylinder minus
  41. 41. 5/2 Valve actuator control - +For a double actingcylinder the power andexhaust paths areswitched simultaneouslyWhen the button ispushed the supply at port 4 2 14 121 is connected to port 4and the outlet port 2 5 1 3connected to exhaustport 3. The cylindermoves plusWhen the button isreleased port 1 isconnected to port 2 andport 4 connected to port5. Cylinder minus
  42. 42. 5/2 Valve actuator control - +Independent speedcontrol of the plus andminus movementsIn most applicationsspeed is controlled byrestricting air out of a 4 2 14 12cylinderFull power is developed 5 1 3to drive the piston withspeed controlled byrestricting the backpressure
  43. 43. 5/2 Valve actuator control - +Independent speedcontrol of the plus andminus movementsIn most applicationsspeed is controlled byrestricting air out of a 4 2 14 12cylinderFull power is developed 5 1 3to drive the piston withspeed controlled byrestricting the backpressure
  44. 44. 5/2 Valve actuator control - +Valves with a springreturn are mono-stableand need the operator tobe held all the time thatthe cylinder is required inthe plus position 4 2Bi-stable valves will stay 14 12in the position they were 5 1 3last setThe lever valve exampleillustrated indicates adetent mechanism. Thelever need not be heldonce the new positionhas been established
  45. 45. Manual control - +Remote manual control ofa double acting cylinderValve marked + will causethe cylinder to outstrokeor move plusValve marked - will cause 4 2 14 12the cylinder to instroke ormove minus 5 1 3The 5/2 double pilot valveis bi-stable therefore the 2 2push button valves only 12 10 12 10need to be pulsed + 3 1 - 3 1
  46. 46. Manual control - +Remote manual control ofa double acting cylinderValve marked + will causethe cylinder to outstrokeor move plusValve marked - will cause 4 2 14 12the cylinder to instroke ormove minus 5 1 3The 5/2 double pilot valveis bi-stable therefore the 2 2push button valves only 12 10 12 10need to be pulsed + 3 1 - 3 1
  47. 47. Manual control - +Remote manual control ofa double acting cylinderValve marked + will causethe cylinder to outstrokeor move plusValve marked - will cause 4 2 14 12the cylinder to instroke ormove minus 5 1 3The 5/2 double pilot valveis bi-stable therefore the 2 2push button valves only 12 10 12 10need to be pulsed + 3 1 - 3 1
  48. 48. Manual control - +Remote manual control ofa double acting cylinderValve marked + will causethe cylinder to outstrokeor move plusValve marked - will cause 4 2 14 12the cylinder to instroke ormove minus 5 1 3The 5/2 double pilot valveis bi-stable therefore the 2 2push button valves only 12 10 12 10need to be pulsed + 3 1 - 3 1
  49. 49. Manual control - +Remote manual control ofa double acting cylinderValve marked + will causethe cylinder to outstrokeor move plusValve marked - will cause 4 2 14 12the cylinder to instroke ormove minus 5 1 3The 5/2 double pilot valveis bi-stable therefore the 2 2push button valves only 12 10 12 10need to be pulsed + 3 1 - 3 1
  50. 50. Semi-automatic control - +Manual remote start of a a1double acting cylinder Awith automatic returnCylinder identified as “A”Trip valve operated at thecompletion of the plus 4 2 14 12stroke identified as “a1” 5 1 3 2 2 12 10 12 10 + 3 1 - a1 3 1
  51. 51. Fully-automatic control - + a0 a1 Continuous automatic A cycling from roller operated trip valves Manual Run and End of the automatic cycling 4 2 14 12 Cylinder will come to rest in the instroked position 5 1 3 regardless of when the 2 10 valve is put to End12Run/End 3 1 Tags for the roller 2 2 feedback valves a0 and 12 10 12 10 a1 show their relative a0 3 1 a1 3 1 positions
  52. 52. Sequential control
  53. 53. Circuit building blocks a0 a1 b0 b1 A B Run/EndThese circuits can be considered as building blocks forlarger sequential circuits consisting of two or morecylindersEach actuator will have a power valve and two associatedfeedback valves. The first actuator to move also hasa Run/End valve
  54. 54. Repeat pattern sequenceA repeat pattern The signal starting thesequence is one where first movement must passthe order of the through the Run/Endmovements in the first valvehalf of the sequence is Needs only the basicrepeated in the second building blocks to solvehalf Examples of repeatEach actuator may have pattern sequences:one Out and In stroke A+ B+ C+ D+ A- B- C- D-only in the sequence A- B+ C- A+ B- C+There may be any numberof actuators in the C+ A+ B- C- A- B+sequence
  55. 55. Repeat pattern sequence a0 a1 b0 b1 A B Run/End b0 b1 a1 a0The two cylinders A and B are to perform a simple repeatpattern sequence as follows: A+ B+ A- B-Apply the rule “The signal given by the completion of eachmovement will initiate the next movement”In this way the roller valves can beidentified and labelled
  56. 56. Repeat pattern sequence a0 a1 b0 b1 c0 c1 A B CRun/End c0 c1 a1 a0 b1 b0 For three cylinders A, B and C also to perform a simple repeat pattern sequence as follows: A+ B+ C+ A- B- C- Apply the rule “The signal given by the completion of each movement will initiate the next movement”
  57. 57. Non-repeat pattern sequence a0 a1 b0 b1 A B Run/End a0 b0 a1 b1If the rule applied to a repeat pattern sequence is appliedto any other sequence there will be opposed signals onone or more of the 5/2 valves preventing operationThis circuit demonstrates the problemThe sequence is A+ B+ B- A-
  58. 58. Opposed signals a0 a1 b0 b1 A B Run/End a0 b0 a1 b1When the valve is set to Run, cylinder A will not movebecause the 5/2 valve has an opposed signal, it is stillbeing signalled to hold position by the feedback valve b0If A was able to move + a similar problem will occur for the5/2 valve of B once it was +The sequence is A+ B+ B- A-
  59. 59. Mechanical solution a0 a1 b0 b1 A B Run/End a0 b0 a1 b1The problem was caused by valves b0 and a1 beingoperated at the time the new opposing instruction is givenIf these two valves were “one way trip” types and overtripped at the last movement of stroke, only a pulse wouldbe obtained instead of a continuous signal
  60. 60. Sequence solution methodsThe main solutions to Shift register circuits aresolving sequences are: similar to cascade but Cascade (pneumatic) use one logic valve for Shift register every step (pneumatic) Electro-pneumatic Electro-pneumatic circuits use solenoid PLC (Programmable valves and electro- logic controller) mechanical relaysCascade circuits provide PLC. The standarda standard method of solution for medium tosolving any sequence. It complex sequentialuses a minimum of systems (except whereadditional logic hardware electrical equipment(one logic valve per group cannot be used)of sequential steps)
  61. 61. Cascade two groupThe A+ B+ B- A- circuit is Because only one groupsolved by the two group output is available at acascade method time it is not possible toThe sequence is divided have opposed signalsat the point where B A standard 5/2 doubleimmediately returns pressure operated valveThe two parts are is the cascade valveallocated groups l and ll Group l Group llGp l A+ B+ / Gp ll B- A-Two signal supplies are 4 2 14 12provided from a 5/2 valveone is available only in Select l 5 1 3 Select llgroup l the other isavailable only in group ll
  62. 62. Cascade (two group) a0 a1 b0 b1 A B b0 a1 Gp l Gp ll Sequence Gp l A+ B+ Gp ll B- A- Run/End a0 b1
  63. 63. Cascade (two group) a0 a1 b0 b1 A B b0 a1 Gp l Gp ll Sequence Gp l A+ B+ Gp ll B- A- Run/End a0 b1
  64. 64. Cascade (two group) a0 a1 b0 b1 A B b0 a1 Gp l Gp ll Sequence Gp l A+ B+ Gp ll B- A- Run/End a0 b1
  65. 65. Cascade (two group) a0 a1 b0 b1 A B b0 a1 Gp l Gp ll Sequence Gp l A+ B+ Gp ll B- A- Run/End a0 b1
  66. 66. Cascade (two group) a0 a1 b0 b1 A B b0 a1 Gp l Gp ll Sequence Gp l A+ B+ Gp ll B- A- Run/End a0 b1
  67. 67. Cascade (two group) a0 a1 b0 b1 A B b0 a1 Gp l Gp ll Sequence Gp l A+ B+ Gp ll B- A- Run/End a0 b1
  68. 68. Cascade building blocksA two group buildingblock consists of a levervalve to run and end the Gp lsequence plus the 5/2double pilot operated Gp ll 4 2cascade valve 14 12For a two group system 5 1 3 Sel llconsisting of any number Run/End 2of cylinders this building 10block and the cylinder 12 3 1building blocks are all Sel lthat is required to solvethe sequence
  69. 69. Cascade building blocksThis three group Gp lbuilding blockestablishes an Run/Endinterconnectingpattern that can Gp llbe extended to Sel lany number of Sel llgroups Gp lll Sel lll
  70. 70. Dual trip building blocksWhen a sequence has a Send A+cylinder operating twice a1 in xin one overall sequence adual trip building block a1 in ymay be required for eachof the two feedbackvalves A+ in A+ inThe supply will be from Group x Group ydifferent groups and the a1output go to differentdestinationsExample is for feedback Note: can often be rationalised to lessvalve a1 of cylinder A than these three componentswhen A is sent + both inGroup x and Group y
  71. 71. Cascade rulesEstablish the correct Interconnect the blocks as follows:sequence The first function in each groupDivide the sequence in to is signalled directly by thatgroups. Always start a group supplysequence with the The last trip valve operated inRun/End valve selecting each group is supplied with main supply air and selects thegroup l e.g. next groupR/E | A+ B+ | B- C+ | C- A- The remaining trip valves areSelect the cylinder supplied with air from theirbuilding blocks respective groups and initiate the next functionSelect the cascade The “run/end” valve will controlbuilding block the signal from the last tripSelect dual trip building valve to be operatedblocks if required
  72. 72. Three position valves
  73. 73. 5/3 Valve5/3 valves have a third The majority ofmid position applications are actuatorThe valve can be tri- positioning and safetystable e.g. a detented 4 2lever operator or mono- 14 12stable e.g. a double air or 5 1 3double solenoid withspring centre 14 4 2 12There are three commonconfigurations for the mid 5 1 3position: 14 4 2 12 All ports blocked Centre open exhaust 5 1 3 Centre open pressure
  74. 74. 5/3 Valve actuator controlThe valve illustrated has“all ports blocked” in themid positionWhenever the mid 4 2position is selected thepressure conditions inthe cylinder will be frozen 14 12This can be used to stop 5 1 3the piston at part strokein some positioningapplicationsFlow regulators mountedclose to the cylinder tominimise creep
  75. 75. 5/3 Valve actuator controlThe valve illustrated has“all ports blocked” in themid positionWhenever the mid 4 2position is selected thepressure conditions inthe cylinder will be frozen 14 12This can be used to stop 5 1 3the piston at part strokein some positioningapplicationsFlow regulators mountedclose to the cylinder tominimise creep
  76. 76. 5/3 Valve actuator controlThe valve illustrated has“all ports blocked” in themid positionWhenever the mid 4 2position is selected thepressure conditions inthe cylinder will be frozen 14 12This can be used to stop 5 1 3the piston at part strokein some positioningapplicationsFlow regulators mountedclose to the cylinder tominimise creep
  77. 77. 5/3 Valve actuator controlThe valve illustrated has“all ports blocked” in themid positionWhenever the mid 4 2position is selected thepressure conditions inthe cylinder will be frozen 14 12This can be used to stop 5 1 3the piston at part strokein some positioningapplicationsFlow regulators mountedclose to the cylinder tominimise creep
  78. 78. 5/3 Valve actuator controlThe valve illustrated has“all ports blocked” in themid positionWhenever the mid 4 2position is selected thepressure conditions inthe cylinder will be frozen 14 12This can be used to stop 5 1 3the piston at part strokein some positioningapplicationsFlow regulators mountedclose to the cylinder tominimise creep
  79. 79. 5/3 Valve actuator controlThis version of a 5/3 valveis “centre open exhaust”The supply at port 1 isisolated and the cylinderhas power exhaustedwhen this centre position 14 4 2 12is selectedThe version illustrated 5 1 3shows a mono-stableversion double pilotoperated spring centreThe cylinder will be pre-exhausted whenchanging from the midposition
  80. 80. 5/3 Valve actuator controlThis version of a 5/3 valveis “centre open pressure”The supply at port 1 isconnected to both sidesof the cylinder and theexhaust ports isolated 14 4 2 12when this centre positionis selected 5 1 3Can be used to balancepressures in positioningapplicationsThe version illustrated ismono-stable, doublesolenoid, spring centre
  81. 81. Logic functions for poppet and spool valves
  82. 82. Logic ANDTo obtain the output Zboth plungers X AND Y Zmust be operated and 2held 12 10 YIf X only is operated the 3 1air will be blocked at port1 in valve YIf Y only is operated there 2 12 10will be no pressure Xavailable at port 1 3 1If either X or Y is releasedthe output signal Z will belost
  83. 83. Logic ANDTo obtain the output Zboth plungers X AND Y Zmust be operated and 2held 12 10 YIf X only is operated the 3 1air will be blocked at port1 in valve YIf Y only is operated there 2 12 10will be no pressure Xavailable at port 1 3 1If either X or Y is releasedthe output signal Z will belost
  84. 84. Logic ANDTo obtain the output Zboth plungers X AND Y Zmust be operated and 2held 12 10 YIf X only is operated the 3 1air will be blocked at port1 in valve YIf Y only is operated there 2 12 10will be no pressure Xavailable at port 1 3 1If either X or Y is releasedthe output signal Z will belost
  85. 85. Logic ANDTo obtain the output Zboth plungers X AND Y Zmust be operated and 2held 12 10 YIf X only is operated the 3 1air will be blocked at port1 in valve YIf Y only is operated there 2 12 10will be no pressure Xavailable at port 1 3 1If either X or Y is releasedthe output signal Z will belost
  86. 86. Logic ANDTo obtain the output Zboth plungers X AND Y Zmust be operated and 2held 12 10 YIf X only is operated the 3 1air will be blocked at port1 in valve YIf Y only is operated there 2 12 10will be no pressure Xavailable at port 1 3 1If either X or Y is releasedthe output signal Z will belost
  87. 87. Logic ANDTo obtain the output Zboth plungers X AND Y Zmust be operated and 2held 12 10 YIf X only is operated the 3 1air will be blocked at port1 in valve YIf Y only is operated there 2 12 10will be no pressure Xavailable at port 1 3 1If either X or Y is releasedthe output signal Z will belost
  88. 88. Logic ANDTo obtain the output Zboth plungers X AND Y Zmust be operated and 2held 12 10 YIf X only is operated the 3 1air will be blocked at port1 in valve YIf Y only is operated there 2 12 10will be no pressure Xavailable at port 1 3 1If either X or Y is releasedthe output signal Z will belost
  89. 89. Logic ANDThis method must not beused as a two handed Zsafety control 2 12 10It is too easy to abuse. Ye.g. one of the buttons 3 1could be permanentlyfixed down and thesystem operated from the 2 12 10other button only XUse the purpose 3 1designed two handedsafety control unit
  90. 90. Logic ORUse of an ‘OR’ functionshuttle valve ZSource X and Y can beremote from each otherand remote from thedestination of ZWhen X or Y is operated 12 2 10the shuttle valve seal Ymoves across to prevent 3 1the signal Z from being 2 12 10lost through the exhaust X 3 1of the other valve
  91. 91. Logic ORUse of an ‘OR’ functionshuttle valve ZSource X and Y can beremote from each otherand remote from thedestination of ZWhen X or Y is operated 12 2 10the shuttle valve seal Ymoves across to prevent 3 1the signal Z from being 2 12 10lost through the exhaust X 3 1of the other valve
  92. 92. Logic ORUse of an ‘OR’ functionshuttle valve ZSource X and Y can beremote from each otherand remote from thedestination of ZWhen X or Y is operated 12 2 10the shuttle valve seal Ymoves across to prevent 3 1the signal Z from being 2 12 10lost through the exhaust X 3 1of the other valve
  93. 93. Logic ORUse of an ‘OR’ functionshuttle valve ZSource X and Y can beremote from each otherand remote from thedestination of ZWhen X or Y is operated 12 2 10the shuttle valve seal Ymoves across to prevent 3 1the signal Z from being 2 12 10lost through the exhaust X 3 1of the other valve
  94. 94. Logic ORUse of an ‘OR’ functionshuttle valve ZSource X and Y can beremote from each otherand remote from thedestination of ZWhen X or Y is operated 12 2 10the shuttle valve seal Ymoves across to prevent 3 1the signal Z from being 2 12 10lost through the exhaust X 3 1of the other valve
  95. 95. Logic NOTA logic NOT applies to thestate of the output whenthe operating signal ispresent (the output issimply an inversion of the Zoperating signal) 2 12 10The valve shown is a X 1 3normally open type (inletport numbered 1)When the signal X ispresent there is NOToutput ZWhen X is removedoutput Z is given
  96. 96. Logic NOTA logic NOT applies to thestate of the output whenthe operating signal ispresent (the output issimply an inversion of the Zoperating signal) 2 12 10The valve shown is a X 1 3normally open type (inletport numbered 1)When the signal X ispresent there is NOToutput ZWhen X is removedoutput Z is given
  97. 97. Logic NOTA logic NOT applies to thestate of the output whenthe operating signal ispresent (the output issimply an inversion of the Zoperating signal) 2 12 10The valve shown is a X 1 3normally open type (inletport numbered 1)When the signal X ispresent there is NOToutput ZWhen X is removedoutput Z is given
  98. 98. Logic MEMORYA logic MEMORY allowsthe output signal state(ON or OFF) to bemaintained after the inputsignal has been removed ZAny bi-stable valve is a Xlogic MEMORY 12 10 3 1With this lever detented Yvalve, once the lever hasbeen moved X directionor Y direction it can bereleased and will stay inthat position
  99. 99. Logic MEMORYA logic MEMORY allowsthe output signal state(ON or OFF) to bemaintained after thesignal that set it has been Zremoved 12 10 X Y 3 1
  100. 100. Logic MEMORYA bi-stable double pilot Zvalve can be set or resetsimply by a pulse (push 12 10and release) on buttons X 3 1or Y 2 12 10 Y 3 1 2 12 10 X 3 1
  101. 101. Logic MEMORYA bi-stable double pilot Zvalve can be set or resetsimply by a pulse (push 12 10and release) on buttons X 3 1or Y 2 12 10 Y 3 1 2 12 10 X 3 1
  102. 102. Logic MEMORYA bi-stable double pilot Zvalve can be set or resetsimply by a pulse (push 12 10and release) on buttons X 3 1or Y 2 12 10 Y 3 1 2 12 10 X 3 1
  103. 103. Logic MEMORYA bi-stable double pilot Zvalve can be set or resetsimply by a pulse (push 12 10and release) on buttons X 3 1or Y 2 12 10 Y 3 1 2 12 10 X 3 1
  104. 104. Logic MEMORYA bi-stable double pilot Zvalve can be set or resetsimply by a pulse (push 12 10and release) on buttons X 3 1or Y 2 12 10 Y 3 1 2 12 10 X 3 1
  105. 105. Logic MEMORY (latch)A popular memory circuitis the latch ZWill not re-make after 1 3pneumatic power failure Y 12 10A pulse on X operates the 2pilot / spring valve to give 12 10output Z 3 1A feedback from Z runsthrough the normally 2 12 10open valve Y to latch the Xoperation of Z when X is 3 1releasedA pulse on Y breaks thelatch and Z is exhausted
  106. 106. Logic MEMORY (latch)A popular memory circuitis the latch ZWill not re-make after 1 3pneumatic power failure Y 12 10A pulse on X operates the 2pilot / spring valve to give 12 10output Z 3 1A feedback from Z runsthrough the normally 2 12 10open valve Y to latch the Xoperation of Z when X is 3 1releasedA pulse on Y breaks thelatch and Z is exhausted
  107. 107. Logic MEMORY (latch)A popular memory circuitis the latch ZWill not re-make after 1 3pneumatic power failure Y 12 10A pulse on X operates the 2pilot / spring valve to give 12 10output Z 3 1A feedback from Z runsthrough the normally 2 12 10open valve Y to latch the Xoperation of Z when X is 3 1releasedA pulse on Y breaks thelatch and Z is exhausted
  108. 108. Logic MEMORY (latch)A popular memory circuitis the latch ZWill not re-make after 1 3pneumatic power failure Y 12 10A pulse on X operates the 2pilot / spring valve to give 12 10output Z 3 1A feedback from Z runsthrough the normally 2 12 10open valve Y to latch the Xoperation of Z when X is 3 1releasedA pulse on Y breaks thelatch and Z is exhausted
  109. 109. Logic MEMORY (latch)A popular memory circuitis the latch ZWill not re-make after 1 3pneumatic power failure Y 12 10A pulse on X operates the 2pilot / spring valve to give 12 10output Z 3 1A feedback from Z runsthrough the normally 2 12 10open valve Y to latch the Xoperation of Z when X is 3 1releasedA pulse on Y breaks thelatch and Z is exhausted
  110. 110. Logic arrangements for fully balanced spool valves
  111. 111. Logic circuits (spool valves) NO / NC 5/2 OR Selection / Diversion Single pulse control Latch Air conservation OR, AND, NOT Double flow Single pulse maker Counting Slow pressure build Pre-selectClick the section to advance directly to it
  112. 112. 3/2 NO / NCA fully balanced valveallows pressure on anypot or combination of 12 2 10ports 3 1A single valve can beused normally open ornormally closedFor normally open the 2supply pressure is 12 10connected to port 1 3 1For normally closed thesupply pressure isconnected to port 3
  113. 113. 3/2 NO / NCA fully balanced valveallows pressure on anypot or combination of 12 2 10ports 3 1A single valve can beused normally open ornormally closedFor normally open the 2supply pressure is 12 10connected to port 1 3 1For normally closed thesupply pressure isconnected to port 3
  114. 114. 3/2 Valve selection / diversionSelection of one of twosupplies connected toports 1 and 3 can be 12 2 10different pressures 3 1Diversion of one supplyto one of two outletsIf it is required to exhaustthe downstream air a 5/2valve is required 3 1 12 10 2
  115. 115. 3/2 Valve selection / diversionSelection of one of twosupplies connected toports 1 and 3 can be 12 2 10different pressures 3 1Diversion of one supplyto one of two outletsIf it is required to exhaustthe downstream air a 5/2valve is required 3 1 12 10 2
  116. 116. Latch with controls OutIn this version of a latchthe push button valves 12 2 10are connected to perform 3 1‘OR’ and ‘NOT’ functionsThe ‘OFF’ valve must be ON 2 12 10placed last in the signalchain so that if both 3 1valves are operatedtogether the ‘OFF’ 2 OFF 12 10command will dominateover the ‘ON’ command 3 1
  117. 117. OR, AND, NOT z 2A single 3/2 pilot operated OR 12 10spring return valve can be 3 1use for any of these logicfunctions x yx OR y gives output z z 2x AND y gives output z AND 12 10x gives NOT z 3 1 x y z 2 NOT 12 10 3 1 x
  118. 118. Single pulse makerConverts a prolongedsignal x into a single zpulse z 2Signal z must be removed 12 10to allow the valve to reset 3 1then x can be appliedagainThe duration of the pulsecan be adjusted with theflow regulator x
  119. 119. Slow initial pressure build upChoose a 3/2 pilot springvalve with a relatively 2high operating force e.g. 12 103 to 4 bar 3 1When the quick connectcoupling is made, theoutput at port 2 iscontrolled at the rate ofthe flow regulator settingWhen the pressure ishigh enough to operatethe valve full flow will takeover
  120. 120. Pre-selectThe lever valve can pre-select the movement ofthe cylinder OUT or IN 2 12 10The movement will occurthe next time the plunger 3 1valve is operated 2 12 10The plunger valve can bereleased immediately and 3 1subsequently operatedand released any number 2 10of times 12 3 1 OUT/IN pre-select
  121. 121. 5/2 OR functionThe valve at position ‘a’ isreversed connected andsupplied from the valveconventionally connected 4 2 12at position ‘b’ a 14The cylinder can be 5 1 3controlled from eitherposition ‘a’ ‘OR’ position 4 2‘b’ 12 b 14 5 1 3
  122. 122. Single pulse controlEach time the footoperated valve ispressed the cylinderwill single stroke + 4 2 12and - alternately 14First foot operation 5 1the cylinder moves 2 2 12 10 12 10outSecond foot 3 1 3 1operation thecylinder moves inThird….. out and soon 12 2 10 3 1
  123. 123. Air conservationPower stroke in theinstroke direction onlyDifferential area of thepiston gives an outstroke 4 2 12force when the pressure 14is balanced 5 1Air used to outstroke isequivalent to a cylinderwith only the same boreas the rod diameterAssumes the cylinder isnot loaded on the plusstroke and low friction
  124. 124. Air conservationPower stroke in theinstroke direction onlyDifferential area of thepiston gives an outstroke 4 2 12force when the pressure 14is balanced 5 1Air used to outstroke isequivalent to a cylinderwith only the same boreas the rod diameterAssumes the cylinder isnot loaded on the plusstroke and low friction
  125. 125. Double flowWhere a larger 3/2 valveis not availableTwo flow paths in a 5/2valve each with a 4 2 14 12separate supply can bearranged to give double 5 1 3flow or supply separatedevicesEnsure the tube size tothe cylinder is largeenough to take the doubleflow
  126. 126. Double flowWhere a larger 3/2 valveis not availableTwo flow paths in a 5/2valve each with a 4 2 14 12separate supply can bearranged to give double 5 1 3flow or supply separatedevicesEnsure the tube size tothe cylinder is largeenough to take the doubleflow
  127. 127. Counting 4Counting applications arebest achieved withelectro-mechanical or 3programmable electroniccountersPneumatic countingcircuits use large 2numbers of logic valvesand can be slowThe counting chainshown will count to 4 1Red and blue are non-overlapping alternatepulses, purple is the resetline
  128. 128. Counting application a0 a1The counting circuit is Aapplied to count 4 strokesof a cylinderAt rest all counting valvesare held reset by the startvalveStart outstrokes ‘A’Alternate signals from‘a1’ and ‘a0’ progressesoperation of the counting Startvalves up the chainOn the 4th operation of‘a1’ the green signal a1 a0resets the start valve tostop the cylinder
  129. 129. Feedback methods
  130. 130. Time delayA signal is restricted toslow the rate of pressurebuild up on a pressure Outputswitch (3/2 differentialpressure operated valve) 2 12 10When the pressure switchoperates a strong un- 3 1restricted output is givenA reservoir providescapacitance to allow less Signalfine and sensitive insettings on the flowregulator making it easyto adjust
  131. 131. Time delay - +Manual remote start of a a1double acting cylinder Awith a time delay in theoutstroked positionbefore automatic return 4 2 14 12 5 1 3 2 12 10 3 1 2 2 12 10 12 10 3 1 a1 3 1
  132. 132. Pressure decay - +Manual remote start of a a1double acting cylinder AUses a low pressureoperated valve connectednormally open 4 2When the back pressure 14 12in the front of the cylinder 5 1 3falls below 0.1 bar thereturn signal is given 2Connection taken 12 10 10 2 12between the cylinder andflow regulator 3 1 1 3 0.1barUseful for pressing workpieces of variable size
  133. 133. Electro-pneumaticThe majority of systems Circuit building block foruse electrical/electronic each cylindercontrol due to the high a0 a1degree of sophisticationand flexibility ASolenoid valves are usedto control cylindersFeedback signals are 4 2from reed switches, 14 12sensors and electrical 5 1 3limit switchesLogic is hard wired orprogrammed in to a PLC a0 a1(programmable logiccontroller)
  134. 134. End

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