Plc programing


Published on

  • Be the first to comment

No Downloads
Total views
On SlideShare
From Embeds
Number of Embeds
Embeds 0
No embeds

No notes for slide

Plc programing

  2. 2. PLC The PLC is an assembly of solid state digital logic elements design to make logical decisions and provide outputs. PLC is programmed interface between input sensor &output device. DEK 3113 2
  3. 3. Programmable Logic ControllersAdvantages of PLC : They are fast and designed for the rugged industrial environment. They are attractive on Cost-Per-Point Basis. These Devices are less Proprietary ( E.g.. Using Open Bus Interface.) These Systems are upgraded more Capabilities with dedicated PID and Ethernet Modules.Disadvantages of PLC : PLC one time cost is high To maximize PLC performance a number of IO Modules to be added. PLC hold only one copy DEKprogram. of 3113 3
  4. 4. P L C Components(Hardware) CentralProcessing Unit (CPU) Input Modules Output Modules Power Supply Bus system DEK 3113 4
  5. 5. Advantage of PLC Over RelayRELAY PLC1-More wiring 1-Less wiring2-Changes difficult 2-Changes easy3-More power 3-Low power4-More maintenance 4-Solid state reliability5-Difficult to expand 3113 -Easy to expand DEK 5 5
  6. 6. PLC Cycle Sense the Input Process the Logic Give Output Inputs CPU Outputs DEK 3113 6
  7. 7. Ladder Diagram Ladder diagrams are specialized schematics commonly used to document industrial control logic systems. It is a language or a method to create a program. The first PLCs were programmed with a technique that was based on relay logic wiring schematics. Basic concept of this diagram is similar to the electrical wiring. However in ladder logic, the symbol has changed and been standardized. DEK 3113 7
  8. 8. Ladder Diagram cont.. Type of graphic language automatic control systems. A drawing program of a switching circuit. Called "ladder" diagrams because they resemble a ladder, with two vertical lines representing the power trails (supply power) and circuits are connected in horizontal lines called rungs. Connection between the element in the rung called link. DEK 3113 8
  9. 9. Ladder Diagram Operational Principle Referring to figure below, between these two rails, a horizontal straight line was drawn with two symbols. These two symbols refer to the input and output devices, which are used in the actual process/system. On the left, we put all kinds of input. While on the right, we place all types of the outputs. Once we complete one line of the program it seems like a ladder. This horizontal line which places the input and output make one rung. +24V -0V Input Interface Output DEK 3113 9
  10. 10. Ladder Diagram Symbols Ladder diagram uses standard symbols to represent the circuit components and functions found in a control system. DEK 3113 10
  11. 11. Normally Open Schematics(NO)-Input Schematics DEK 3113 12
  12. 12. Normally Closed Schematics(NC)-Input Schematics DEK 3113 13
  13. 13. Output Schematics DEK 3113 14
  14. 14. Logic Function There are 5 logic functions can be developed by combination of switches 1. AND 2. OR 3. NOR 4. NAND 5. EX-OR (XOR) DEK 3113 15
  15. 15. Logic Function…cont1. AND logic coils is not energized unless both switch A and B closed. Fig. (b) represent for PLC input. DEK 3113 16
  16. 16. Logic Function…cont - AND DEK 3113 17
  17. 17. Logic Function…cont2. OR logic Coils is not energized until either A or B closed DEK 3113 18
  18. 18. Logic Function…cont – OR DeMorgans Theorem would predict: DEK 3113 19
  19. 19. Logic Function…cont3. NOR logic Since there has to be an output when neither A nor B have an input, and when there is an input either A or B. DEK 3113 20
  20. 20. Logic Function…cont -NOR DEK 3113 21
  21. 21. Logic Function…cont4. NAND logic There is no output when both A and B have an input DEK 3113 22
  22. 22. Logic Function…cont -NAND DEK 3113 23
  23. 23. Logic Function…cont - NOT DEK 3113 24
  24. 24. Logic Function…cont5. XOR logic There is no output when both input 1 and 2 given. DEK 3113 25
  25. 25. Combination of AND, OR, andinverter (NOT) gates DEK 3113 26
  26. 26. Control Circuit Start stop circuit-PB is pressed, output IR is activated-IR contact will closed-When PB is depressed, the output IR is stillactivated since current can go through contact IRunless is disturbed by stop button. DEK 3113 27
  27. 27. Vibrating/Jog circuit-When, PB is pressed, output IR is activated. -When, PB is pressed, output IR is activated.-But after several microsecond, the normally closed IR is -But after several microsecond, the normally closed IR isopen then will stop the output IR. open then will stop the output IR.-This applicable to move an object which need to locate -This applicable to move an object which need to locateat precise location. at precise location. DEK 3113 28
  28. 28. DEK 3113 29