Bits And Bytes

PLC Program to Drive Motors Simultaneously with Interlocking

Problem Description

Two Motors are running in a sequence one by one for a particular time. If the start button is pressed Motors run in sequence such that 1st Motor stays ON for 5secs and then 2nd Motor is turned ON and stays ON for 5secs. And the cycle is repeated until it is interrupted. While motors are running in the sequence, if one motor is running and the button of other motor is pressed, then the running Motor should stop and the other motor should run. Implement this logic in PLC using Ladder Diagram programming language.

Problem Solution

  • Define addresses of motors.
  • Create latching seal in contact to start and stop the sequential operation.
  • Use TON timer to generate a particular time delay, same or different.
  • Use DN bit of first timer to energize 2nd motor coil and activate second timer.
  • No need to use Reset coils, program will reset the timers itself after completion of each cycles.
  • Use Parallel Start Motor contact to start one motor when other motor is running.

PLC Program

Here is PLC program to Drive Motors Simultaneously with Interlocking, along with program explanation and run time test cases.

List of Inputs and Outputs

I:1/0 = Motor0 Start (Input)
I:1/1 = Motor2 Stop (Input)
I:1/2 = Master Start (Input)
I:1/3 = Master Stop (Input)
O:2/2 = Master Coil (Output)
O:2/0 = Motor0 (Output)
T4:0 = Motor0 Timer (Timer)
O:2/1 = Motor1 (Output)
T4:1 = Motor1 Timer (Timer)