1. SEMINAR ON P.L.C. SUBMITTED BY HRIDAY MUKHERJEE 08144003062 AMIT DEBNATH 08144003063 SOMNATH SHIL 08144003064

2. INTRODUCTION TO PLC PROGRAMMABLE LOGIC CONTROLLER A digitally operating electronic apparatus which uses a programming memory for the internal storage of instructions for implementing specific functions such as logic, sequencing, timing, counting and arithmetic to control through digital or analog modules, various types of machines or process.

3. PROGRAMMABLE CONTROLLER DEVELOPMENT 1968 Programmable concept developed 1974 Use of several (multi) processors within a PLC - timers and counters; arithmetic operations. 1977 Microprocessors - based PLC introduced

4. PROGRAMMABLE CONTROLLER DEVELOPMENT 1983 Low - cost small PLC’s introduced 1985 on Networking of all levels of PLC, computer and machine using software

5. IN PLC TANK LEVEL TRANSMITTER EXAMPLE OF PLC OUT

6. 6 MAJOR COMPONENT OF A PLC PROCESSOR POWER SUPPLY I M N O P D U T L E O M U O T D P U U L T E PROGRAMMING DEVICE From SENSORS Pushbuttons, contacts, limit switches, etc. To OUTPUT Solenoids, contactors, alarms etc.

7. COMPONENT OF PLC  POWER SUPPLY Provides the voltage needed to run the primary PLC component  I/O MODULES Provides signal conversion and isolation between the internal logic- level signals inside the PLC and the field’s high level signal

8. COMPONENT OF A PLC  PROCESSOR Provides intelligence to command and govern the activities of the entire PLC systems  PROGRAMMING DEVICE Used to enter the desired program that will determine the sequence of operation and control of process equipment or driven machine

9. ARCHITECTURE

10. PLC OPERATION CHECK INPUT STATUS EXECUTE PROGRAM UPDATE AND OUTPUT STATUS

11. PLC OPERATION  CHECK INPUT STATUS First the PLC scans each input to determine if it is ON or OFF. It records this data into its memory to be used the next steps.  EXECUTE PROGRAM Next the PLC executes the program one at a time.  UPDATE OUTPUT STATUS Finally the PLC updates the status of the outputs.

12. CONFIGURATION  RELAYS: This are connected to the outside world. They are physically exist.  COUNTERS: They do not physically exist. They are simulated and can be programmed to count pulses.  TIMERS: They also do not physically exist. Common type are ON delay and OFF delay.  DATA STORAGE: Typically there are register to store data.

13. network binary inputs binary outputs analog inputs / outputs A SIMPLE PLC

14. PLC INPUTSOUTPUTS CONTACTOR PUSHBUTTONS

15. PLC PROGRAMMING PLC programs are typically written in a special application on a personal computer, then downloaded by a direct-connection cable or over a network to the PLC. The program is stored in the PLC either in battery-backed-up RAM or some other non-volatile flash memory. Often, a single PLC can be programmed to replace thousands of relays. LADDER LOGIC:

16. ELEMENTS OF LADDER LOGIC NORMALLY OPEN NORMALLY CLOSED (CONTACT) Power flows through these contacts when they are closed. The normally open (NO) is true when the input or output status bit controlling the contact is 1. The normally closed (NC) is true when the input or output status bit controlling the contact is 0.

17. ELEMENTS OF LADDER LOGIC COILS Coils represent relays that are energized when power flows to them. When a coil is energized it causes a corresponding output to turn on by changing the state of the status bit controlling the output to 1. That same output status bit maybe used to control normally open or normally closed contact anywhere in the program.

18. LADDER LOGIC EXAMPLE OR OPERATION A B C In the above, it can be seen that either input A or B is be true (1), or both are true, then the output C is true (1).

19. PLC MEMORY The memory system in the processor module has two parts : 1.PROGRAM FILE 2.DATA FILE

20. PLC MEMORY DATA FILE PROGRAM FILE The user program area is where the programmed instructions entered by the user are stored as an application control program Data files are used for stored different information types. In the input and output which interface to outside world, and the other part of data file is fixed types of data files. The content of program memory cannot be changed while the PLC is running.

21. SELECTING A PLC Criteria  Number of logical inputs and outputs.  Memory  Number of special I/O modules  Scan Time  Communications  Software

22. PLC AS A TOOL  achieve consistency in manufacturing.  improve quality and accuracy  increase productivity  shorten the time to the market  quick change over from one product to another  control inventry

23. USER INTERFACE PLCs may need to interact with people for the purpose of configuration, alarm reporting or everyday control.

24. PLC COMMUNICATION  Changing resident PLC programs - uploading/downloading from a supervisory controller (Laptop or desktop computer).  Forcing I/O points and memory elements from a remote terminal.  Linking a PLC into a control hierarchy containing several sizes of PLC and computer.  Monitoring data and alarms, etc. via printers or Operator Interface Units.

25. PLC COMMUNICATION Common Standards  RS 232  RS 485  LAN

26. TYPES OF PLC  Rack: A rack is often large (up to 18” by 30” by 10”) and can hold multiple cards. When necessary, multiple racks can be connected together.  Mini: these are similar in function to PLC racks, but about half the size.  Micro: these units can be as small as a deck of cards. They tend to have fixed quantities of I/O and abilities, but cost will be the lowest.

27. TYPES OF PLC  Software: A software based PLC requires a computer with an interface card, but allows the PLC to be connected to sensor and other PLCs across a network. MICRO MINI RACK

28. LIST OF ITEMS REQUIRED WORKING WITH PLC  Programming Terminal - laptop or desktop PC.  PLC Software  Communication cable for connection from Laptop to PLC.  Backup copy of the ladder program (on diskette, CDROM, hard disk, flash memory).  Documentation- (PLC manual, Software manual, drawings, ladder program printout, and Seq. of Operations manual.)

29. AREA OF APPLICATION  Manufacturing / Machining  Food / Beverage  Metals  Power  Mining  Petrochemical / Chemical

30. ADVANTAGE OF PLC  Cost effective for controlling complex system.  Smaller physical size than hard-wired solutions.  Flexible and can be reapplied to control other systems quickly.  PLCs have integrated diagnostics and override functions.  Computational abilities allow more sophisticated control.  Diagnostics are centrally available.

31.  Troubleshooting aids make programming easier and reduce downtime.  Applications can be immediately documented.  Applications can be duplicated faster and less expensively.  Reliable components make these likely operate for several years successfully.  Communication is possibilities.

32. DISADVANTAGE OF PLC  Programmable controllers are not equipped with enough memory to store big amounts of data.  In this field the communication system need to be more developed.

33. CONCLUSION Programmable Logic Control, or PLC as it is universally called, is the ‘work horse’ of industrial automation. PLCs have been gaining popularity on the factory floor and will probably remain predominant for some time to come. PLCs are an application area where much can be done.

34. THANK YOU!!

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