Pulse counter module contains 2 pulse counters connected to A.3 and A.4 pins.
Each counter can count pulses in one of three modes:
Free Run Mode – Pulses are counted continuously. You can suspend, resume or reset the counter and get the number of pulses at any time.
Time Based Mode – Pulses are counted during the user-defined time period. When the predefined time period is exceeded, the counting starts again from 0 and the pulse counter sends an event to PC. The event contains the number of pulses detected during this period.
Pulse Based Mode – Pulses are counted until the number of pulses reaches the user-defined value. Then the counting starts again from 0 and the counter sends an event to PC. The event contains time elapsed from the moment you started the counter.
For pulse to be counted its high time (T1) and low time (T0) should be greater than 83 ns.
The number of pulses and elapsed time are stored as 3-byte value. This allows to count up to 16,777,215 pulses until the counter overflows. When the counter overflows, it doesn't stop. The GPIO-24 adapter resets the counter, and counting starts again from 0. You can configure the counter to send an event, when it overflows.