Frequency counter module has two frequency counters. Either of them can measure frequency of a digital signal on A.3 or A.4 pin. Frequency is measured by counting the number of pulses on the corresponing
I/O pin per second. Minimum high time (T1) and low time (T0) of a pulse should be 83 ns.
While T1 and T0 are greater than 83 ns, GPIO-24 adapter frequency counter can measure frequency up to 5 MHz.
Any time you can retrieve current frequency with GPIO_GET_FR_CNT_VAL command.
Besides sending measurement results on demand, a frequency counter can generate an event to notify the user when user-defined measurement limits are reached. You can also configure the frequency counter to send events periodically with a predefined repeat interval. For more detailed information see Section 10.1, “Frequency Counter Event”.