PLC Ladder Diagrams.pptx

Presentation on PLC Ladder Diagram Examples

1. Sanjivani College of Engineering, Kopargaon Department of Electronics & Telecommunication Engineering (An Autonomous Institute) Affiliated to Savitribai Phule Pune University Accredited ‘A’ Grade by NAAC ________________________________________________________________________________________ Subject: PLCs and Industrial Automation (ET8204) UNIT-4 Topic: Exercise # 4 Dr. Sebastian George Professor, E&Tc Department

2. Develop a PLC Ladder diagram for a motor with the following: Physically NO Start button Physically NC Stop button Thermal overload limit switch opens on high temperature Green light when running Red light for thermal overload. Dr. Sebastian George E&Tc Department 2 Ladder Diagram Example #1

3. Inputs Outputs START: I:0/10 Motor : O:0/0 STOP : I:0/11 Green light: O:0/1 Thermal overload Red light : O:0/2 Limit switch : I:0/0 START switch is NO. The STOP switch, though physically NC, is interpreted as NO in the programmed ladder. The temperature limit switch is also interpreted as NO. B3/12 is Bit No. 12 of binary file. The bit is used for temporary storage of Rung output status. Dr. Sebastian George E&Tc Department 3 I/O Assignment

4. Dr. Sebastian George E&Tc Department 4 Ladder Diagram

5. Dr. Sebastian George E&Tc Department 5 Example # 2 A bidirectional movable arm is shown in the figure. Develop a ladder diagram to control it as per the following conditions: START push button is physically NO and STOP push button is physically NC. When the system is turned ON, the motor should rotate continuously, alternating between in the counter clockwise and clockwise directions, as the movable arm touches two limit switches, RLS and LLS. Both the limit switches are physically NC.

6. Dr. Sebastian George E&Tc Department 6 Example # 2

7. Dr. Sebastian George E&Tc Department 7 I/O Assignment Inputs Outputs START : I:0/10 CW: O:0/0 STOP: I:0/11 CCW:O:0/1 LLS:I:0/0 RLS:I:0/1

8. Dr. Sebastian George E&Tc Department 8 Ladder Diagram

9. Dr. Sebastian George E&Tc Department 9 Example # 3 Draw a ladder diagram for a two motor system having the following conditions: START push button starts Motor 1 After 10 seconds, Motor 2 is ON STOP push button stops Motor 1&2 START is physically NO and STOP is physically NC

10. Dr. Sebastian George E&Tc Department 10 I/O Assignment Inputs Outputs START : I:0/10 Motor 1 : O:0/0 STOP: I:0/11 Motor 2: O:0/1 In addition, Timer T4:0 is also there in the ladder program. It is ON Delay Timer

11. Dr. Sebastian George E&Tc Department 11 Ladder Diagram

12. Dr. Sebastian George E&Tc Department 12 Example #4 Draw a ladder diagram for a 2 motor system having the following: The START push button starts both motors 1 &2 STOP push button stops motor 1 first and after 15 seconds, stops motor 2

13. Dr. Sebastian George E&Tc Department 13 I/O Assignment START is physically NO and STOP is physically NC. Timer T4:1 is an OFF Delay Timer. Inputs Outputs START : I:0/10 Motor 1 :O:0/0 STOP: I:0/11 Motor 2: O:0/1

14. Dr. Sebastian George E&Tc Department 14 Ladder Diagram

15. Dr. Sebastian George E&Tc Department 15 Example #5 Prepare the ladder diagram for the control problem shown in the figure. The global objective is to heat the liquid toa specified temperature and keep it there for 30 minutes. The event sequence is : Fill the tank Heat and stir the liquid for 30 minutes Empty the tank Repeat from Step 1

16. Dr. Sebastian George E&Tc Department 16 Example #5

17. Dr. Sebastian George E&Tc Department 17 I/O Assignment START push button is physically NO and STOP is physically NC. Level limit switches and Temperature limit switch open on crossing the limits. Timer T4:0 is ON Delay Timer. Inputs Outputs START : I:0/10 VIN : O:0/0 STOP : I:0/11 VOUT : O:0/1 LUP : I:0/0 H: O:0/2 LE :I:0/1 Stir : O:0/3 Temp: I:0/2

18. Dr. Sebastian George E&Tc Department 18 Ladder Diagram

19. Dr. Sebastian George E&Tc Department 19 Example # 6 Draw the ladder diagram for a box packaging system having five boxes stacked at a time and then bound with a wrapper. Box present signal : I:0/0 Wrapper machine relay :O:0/0 Timer T4:1 is an ON Delay Timer and C5:1 is an UP counter

20. Dr. Sebastian George E&Tc Department 20 Ladder Diagram

21. Prof.N.I.Bhopale ,Department of E&Tc Engineering 21 Thank You!