PLC Timers

Timers wait a set duration of time then do something.  An input tells the timer when to start timing.

While timer may be explained differently depending on the PLC line you’re working with, we’ll go over a good solution, knowing other solutions will follow similar concepts:

Data used in examples:

  • Enable starts the timer. (1 input)
  • Duration (also called time-delay) defines the amount of time to wait before doing something. (1 internal integer)
  • Timer Value keeps track of how much time has passed since timing began. (1 internal integer)
  • Timer Bit (1 output bit)

On Timer waits a Duration after an Enable input goes high before turning the Timer Bit on.  The Timer Bit goes low when the Enable input goes low.

On Timers may have a Cumulative Timer options.  If so, you can specify whether you want the Timer Value to reset when Enable goes low.

Off Timer causes Timer Bit to go high when an Enable input goes high and keeps it high for a Duration after the Enable input goes low.