using c200hs for speed indication

[Guest radmaxntx]

what is the fasted pulse i can expect to capture reliably. Is speed indication something that these plc's even can do.

[BobB 58]

The PLC is a bit old and slow but it depends on what you want to count. Basically, there is a small input delay time to take into account. Check what your input card is and then look up the manual for that input card to find out what is the input delay. The biggest issue is that the length of the pulse you wish to count must be at least twice as long as your longest scan time so that you do not miss pulses. You can reduce the time between reads to a certain extent by using interrupt processing or I/O refresh, but, beware, these functions can also extend your scan time if you use them too freely.