A phase/B phase/Z phase indicates the input signal for each counter board.
A phase/B phase is the counting signal name for the counter board. The counter board counts the rising edge and falling edge of these signals. It depends on the mode that which signal's change should be counted.
Refer to [Mono-phase/2-phase/Gate control] and [Multiplier] for details.
Z phase is the signal that zero-clears the count value.
When you use the counter board, it is necessary that you understand the meaning of these signals and set the suitable software parameters according to the type of input signals.