I suppose then if you can see the pulse then, you should be able to do some math calculations based on a timer of how often you see the pulse during that start and end of the timer. There might be other ways but it's "just a thought" as TP puts it. All this would have to be done in the plc script and any pauses or sleeps in the plc script I would assume would affect the results. (another thing to play with) I'm using timers now for tool usages, guess i'll have to see how to use this to check pulse signals. I did use a timer to check length of pulse signal and that worked well.