Plc programing
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The document discusses programmable logic controllers (PLCs). It describes PLCs as digital logic assemblies that make logical decisions and provide outputs. PLCs are programmed to interface between input sensors and output devices. The document outlines some advantages and disadvantages of PLCs. It also describes common PLC components, how PLCs operate in a cycle, and ladder logic programming.
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Plc programing
- 1. PROGRAMMABLE LOGIC CONTROLLER SOFCON INDIA PVT. LTD. MENTOR: SHEKHAR MAURYA PROF. S.K.PAHUJA 09106068 INSTRUMENTATION & CONTROL
- 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. Programmable Logic Controllers Advantages 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. P L C Components(Hardware) CentralProcessing Unit (CPU) Input Modules Output Modules Power Supply Bus system DEK 3113 4
- 5. Advantage of PLC Over Relay RELAY PLC 1-More wiring 1-Less wiring 2-Changes difficult 2-Changes easy 3-More power 3-Low power 4-More maintenance 4-Solid state reliability 5-Difficult to expand 3113 -Easy to expand DEK 5 5
- 6. PLC Cycle Sense the Input Process the Logic Give Output Inputs CPU Outputs DEK 3113 6
- 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. 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. 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. Ladder Diagram Symbols Ladder diagram uses standard symbols to represent the circuit components and functions found in a control system. DEK 3113 10
- 11. Normally Open Schematics (NO)-Input Schematics DEK 3113 12
- 12. Normally Closed Schematics (NC)-Input Schematics DEK 3113 13
- 13. Output Schematics DEK 3113 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. Logic Functioncont 1. AND logic coils is not energized unless both switch A and B closed. Fig. (b) represent for PLC input. DEK 3113 16
- 16. Logic Functioncont - AND DEK 3113 17
- 17. Logic Functioncont 2. OR logic Coils is not energized until either A or B closed DEK 3113 18
- 18. Logic Functioncont OR DeMorgan's Theorem would predict: DEK 3113 19
- 19. Logic Functioncont 3. 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. Logic Functioncont - NOR DEK 3113 21
- 21. Logic Functioncont 4. NAND logic There is no output when both A and B have an input DEK 3113 22
- 22. Logic Functioncont - NAND DEK 3113 23
- 23. Logic Functioncont - NOT DEK 3113 24
- 24. Logic Functioncont 5. XOR logic There is no output when both input 1 and 2 given. DEK 3113 25
- 25. Combination of AND, OR, and inverter (NOT) gates DEK 3113 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 still activated since current can go through contact IR unless is disturbed by stop button. DEK 3113 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 is open 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 locate at precise location. at precise location. DEK 3113 28
- 28. DEK 3113 29