what is maximum frequency of digital pulses  can digital input module of s7 300 respond?

thank you very much

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Split from counter for measure frequency.

Hi!

Standard inputs - it does depend from your plc scan time as well -

typical scan time is ca 20ms (but seen programs having 140ms scan time) so imagine you will not catch anything shorter than that. hardware wise input can detect shorter time but PLC program may not see it because of scan time.

high speed inputs can catch up to 10..30kHz depending on the input card or compact PLC type. These are processed by the counters and you get count or frequency. counting can be controlled both by software and hardware gate.