chapter 3 electro pneumatic.updated

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  1. 1. Chapter 3 ELECTRO PNEUMATIC SYSTEM Industrial Electronics DEK 3113
  2. 2. Intro of Electro-pneumatic system
    • Pneumatic products represent a multi-billion dollar industry today.
    • Pneumatic devices are used in many industrial applications.
    • Mostpneumaticdevices aredesignedto useclean dry air as an energy source .
    • Theactuatorthenconvertsthatcompressed airintomechanical motion . Thetype of motionproduceddependson the design of theactuator.
    DEK 3113
  3. 3. Into of electro-pneumatic system
    • -Electro pneumatic system consist of both
    • electricalandpneumaticsystem.
    • -Usage of electro pneumatic includes:
    • 1) Packaging
    • 2) Stamping, shearing & embossing part
    • 3) Sorting part
    • 4) Component stacking
    • 5) Material stacking
    DEK 3113
  4. 4. Example of pneumatic connections/diagram: DEK 3113
  5. 5. Example of electrical wiring/connection DEK 3113
  6. 6. Solenoid symbol which moves the valve. DEK 3113
  7. 7. Directional Control Valve: Port & Position
    • -directional control valve is attach with
    • solenoid, so that it can move forward &
    • backwards.
    • -the movement of the valve is allow
    • compressed air go into the airway of the
    • valve to control the movement of the
    • cylinder.
    DEK 3113
  8. 8. Directional Control Valve: Port & Position..cont DEK 3113 i)Valve switching positions are represented by squares
      • ii) The number of switching positions of the valve is
      • shown by the number of squares
    iii) Lines indicates arrow show the direction of flowpaths iv) Shut off positions are identified in the boxes by linesat right angles v) The connection (inlet and outlet ports) are shown by lines on the outside of the box and are drawn in the initial position.
  9. 9. Several type of valve DEK 3113 Port or connection DIN ISO5599 Lettering System Pressure port 1 P Exhaust port 3 R Exhaust ports 5,3 R,S Signaloutputs 2,4 B,A
  10. 10. Numbering system for pneumatic circuit element
    • 0.1Air supply unit
    • 1.0, 2.0 etcWorking element (cylinder)
    • 1.1,2.1 etcControl Element (solenoid)
    • 1.01,1.02 etcElement btwn control element& working element-
    • one way flow control valve
    DEK 3113
  11. 11. Control of single acting cylinder
    • -rest position, air supply shut off,
    • cylinder retracted by the spring.
    • -when switch closed, current flow
    • to the circuit & start to energize
    • solenoid coil
    • -Magnetic field created, push the
    • plunger that will slide the valve to
    • the right.
    • -This will allow the air to flow inside
    • the piston & extend the piston.
    • -If switch released, the valve will
    • slide back & cause the air to stop.
    DEK 3113
  12. 12. Control of double acting cylinder
    • -rest [
    DEK 3113 -rest position, air supply flowing tothe cylinder piston rod via thevalve and pushing the piston atrest/retraction position-no currentflow to the solenoid -switch closed, energized solenoidcoil-magnetic field develop atsolenoid. -magnetic filed develop push theplunger and cause valve slide tothe right. -this allow air flow inside the pistonvia the other port & push/extendthe valve. -when switch released, current notflow, cause the magnetic field weakerand vanish-valve slide to initialposition.
  13. 13. Basic circuit for electro pneumatic circuit DEK 3113 1) AND 2) OR 3) NOT 4) Memorylatching 5) Dominant reset
  14. 14. Cont.. DEK 3113 6) Dominant set
  15. 15. Process Sequence Description
    • There are several method to describe
    • process sequence:
    • Simple narative
    • Boolean
    • Grafset
    • Motion diagram
    • Displacement diagram
    DEK 3113
  16. 16. Simple narrative
    • A push button is used to turn on the conveyor belt
    • A that brings the bottles to the filing line. Sensor 1
    • that is placed at the center of the conveyor A will
    • stop the conveyor belt A upon detecting the bottle
    • and open the valve for filing for 2 second. After
    • that the conveyor belt will be on again until the bottle is
    • sensed by sensor 2 at the end of conveyor belt A.
    • Conveyor belt A once again stop and the solenoid is
    • energized for 3 seconds in order for the piston to push the
    • bottle to conveyor belt B. The process repeats until stop
    • button is pressed.
    DEK 3113
  17. 17. cont..
    • 1 st : please identify input and output
    • Input: PB,Sensor 1,timer 1 contact(2
    • sec),sensor 2,timer 2 contact(3
    • sec)
    • Output:Conveyor A,valve,timer 1
    • coil(2 sec), solenoid,timer 2
    • coil(3 sec)
    DEK 3113
  18. 18. Cont.
    • 2 nd : Please simplified the narrativestatement
    • PB turns on conveyor A
    • Sensor1stop conveyor A,open valve,timer 1 on for 2 sec
    • After timer 1 times up(after 2 sec),conveyor A on.
    • Sensor 2 stops the conveyor,energize solenoid,timer 2 on for 3 sec.
    • Timer 2 times up(after 3 sec),conveyor A on again.
    • Stop button reset all
    DEK 3113
  19. 19. Boolean
    • Another one method to describe process sequence.
    • Is a logic expression using gates.
    DEK 3113
  20. 20. cont
    • Example:
    • The door of the automatic train will be locked if start button is pushed and will unlocked when sensor 1 detects its arrival at station 1. Sensor 2 that is placed at the entrance door of the train will count the number of train passengers on that day.
    • D= door;D = lock, D= unlock
    • S1= sensor 1;S1= sense , S1 = not sense
    • S2=sensor 2;S2= sense ,S2= not sense
    • SB=start button;SB= pressed,SB = not pressed
    • CNT=counter;RB=reset button ;RB=reset, RB=not reset
    • Boolean:
    • 1.D=SB.S1D=SB.S1
    • 2.CNT=S2.S1.RB
    DEK 3113
  21. 21. Grafset
    • Example:
    • The tank system has the narrative description below:
    • Fill the tank to level A from valve A
    • Fill the tank to level B from valve B
    • Start a timer, heater and stirrer for 5 minutes.
    • Open output valve C until the empty switch engages.
    DEK 3113
  22. 22. Cont. DEK 3113 I/O assignment: input output LA- level AVA valve A LB-Level BVB valve B ES empty switchVC valve C TIM timer contact(5 mins)TIM timer coil(5 min)- times up after 5 min.- timer on for 5 min.SB- start buttonH heater ST- stirrer
  23. 23. cont DEK 3113
  24. 24. Motion Diagram
    • 1) The input and the output are separated with the input at the upper side and the output is at the bottom side.
    DEK 3113
  25. 25. Displacement Diagram
    • 1) Presented in form of graph indicates the position of the cylinders and the displacement
    DEK 3113 Step 1:Cyl1 and Cyl 2 extend Step 2:Cyl 1 retracts while Cyl 2 remainsextend for 3 seconds. Step 3:Cyl 1 remains retracts for 3 secondsand Cyl 2 retracts Step 4- step 6:The position of Cyl 1 and Cyl 2 similar as Step 1 Step 3
  26. 26. Con. DEK 3113
  27. 27. Single Acting Cylinder
    • (a)Spring Retracted Type : A spring retracted single acting cylinder develops thrust in one direction only. The piston rod is returned by the spring
    DEK 3113
  28. 28. Contd
    • 1- Piston
    • 2- Piston rod
    • 3- Return Spring
    • 4- Rod Cover
    • 5- Head Cover
    • 6- Piston Seal
    • 7- Stopper Spring
    • 8- Guiding Ring
    DEK 3113
  29. 29. Contd
    • When compressed air is supplied to the air port, the compressed air will act on the piston extending the piston rod
    DEK 3113
  30. 30. Contd
    • When the compressed air is allowed to vent out of the air port, the spring force will retract the piston rod
    DEK 3113
  31. 31. Single Acting Cylinder
    • (b)Spring Extended Type : A spring extended single acting cylinder develops thrust in one direction only. The piston rod is extended by the spring
    DEK 3113
  32. 32. Contd
    • 1- Piston
    • 2- Piston rod
    • 3- Return Spring
    • 4- Rod Cover
    • 5- Head Cover
    • 6- Piston Seal
    • 7- Stopper Spring
    • 8- Guiding Ring
    DEK 3113
  33. 33. Contd
    • When compressed air is supplied to the air port, the compressed air will act on the piston retracting the piston rod
    DEK 3113
  34. 34. Contd
    • When the compressed air is allowed to vent out of the air port, the spring force will extend the piston rod
    DEK 3113
  35. 35. Double Acting Cylinder
    • A double acting cylinder develops thrust inboth extending and retractingdirections as air pressure is applied alternately to opposite sides of a piston
    DEK 3113
  36. 36. Contd
    • 1- Piston

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