this is a ppt on programmble logic controller

presentation on plc

1. Rewa Engineering College Electronics & Communication INTERNSHIP AT BHEL UNDER THE GUIDANCE OF : PROF. A. K. DOHARE HOD SIR SUBMITTED TO: PROF ANIRUDDH SIR SUBMITTED BY: Shivam Sen ENROLLMENT NO.: 0301EC2110 51 SEMESTER : FIFTH (5 th ) BATCH : 2021-2025

2. Contents What is PLC? His t o r y of P L C M ajor c omp o nent s of P L C Operational sequence of PLC Ladder logic Example of starting and stopping of a motor Advantages Disadvantages Application

3. What is PLC? PLC is a digital computer designed for multiple inputs and output arrangements, extended temperature ranges , immunity to electrical noise , and r esistan c e t o vib r ation and impac t . A PLC is an example of a real time system.

4. PLC was introduced in late 1960’s First commercial & successful Programmable Logic Controllers was designed and developed by Modicon as a relay replacer for General Motors. Earlier, it was a machine with thousands of electronic parts. Later ,in late 1970’s,the microprocessor became reality & greatly enhanced the role of PLC permitting it to evolve form simply relay to the sophisticated system as it is today.

5. 5 Major Components of a Common PLC PROCESSOR PO W ER S U PP L Y I M N O P D U U T L E O M U O T D P U U L T E P R OG R A MM I N G DEVICE From SE N S O R S P ushbu t t ons , contacts, limit switches, etc. To O UT P U T Solenoids, c on t ac t ors , alarms etc.

6. 6 Major Components of a Common PLC POWER SUPPLY Provides the voltage needed to run the primary PLC components I/O MODULES Provides signal conversion and isolation between the internal logic- level signals inside the PLC and the field’s high level signal . 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.

7. PLC operation sequence Self test : Testing of its own hardware and software for faults. Input scan : If there are no problems, PLC will c o p y all t he inp u t s and c o p y t he i r v alu e s into memory. Logic solve/scan : Using inputs, the ladder logic program is solved once and outputs are updated. Output scan : While solving logic the output values are updated only in memory when ladder scan is done, the outputs will be updated using temporary values in memory. Self test In p u t scan L ogic scan Out p ut scan

8. Programming Languages of PLC Most common languages encountered in PLC programming are: Ladder Logic Functional Block Diagram Sequential Function Chart Boolean mnemonics

9. Ladder Logic The ladder logic is the oldest programming language for PLC. It is well suited to express Combinational logic. The main ladder logic symbols represent the elements : ma k e c o n tact b r eak c o n tact r el a y c o i l

10. A B Logic(Y) OFF OFF OFF OFF ON OFF ON OFF OFF ON ON ON AND Gate A B Y A B Logic(Y) OFF OFF OFF OFF ON ON ON OFF ON ON ON ON OR Gate A B Y

11. NOR Gate A B Y A B Logic(Y) OFF OFF ON OFF ON ON ON OFF ON ON ON OFF A B Logic(Y) OFF OFF ON OFF ON OFF ON OFF OFF ON ON OFF NAND Gate B Y A

12. Block diagram of a PLC Outputs LEDs Inputs

13. Ladder Logic Program for Start/Stop of Motor : X2 X1 Y1 Y1

14. Programming PLC:

15. Starting of Motor:

16. Continuous Running of motor when Start Button is released:

17. To Stop the Motor :

18. Reliability. Flexibility in programming and reprogramming. C ost ef f ec t i v e f or c ont r olling c omp l ex s y s t em s . Small physical size, shorter project time. High speed of operation. Ability to communicate with computer systems in the plant. Ease of maintenance /troubleshooting. Reduced space. Energy saving.

19. Disadvantages of PLCs PLC devices are proprietary it means that part or software of one manufacturer can’t be used in combination with parts of another manufacturer. Limited design and cost option Fixed Circuit Operations. P L C s manufactu r ers o f f er o n l y close d a r chi t ect u r e s .

20. Wherever automation is desired the PLCs are best suited to meet the task. Few examples of industries where PLCs are used : Robots manufacturing and control Car park control Train control station system Food processing Materials handling 6)Machine tools 7) C o n v e y er s y s t em e t c.

21. Thank You!!!