The trigger input signal is what causes the device to start the acquisition. The trigger input signal is a transition between logic zero and logic one, therefore the signals are:
Falling edge → change from logic 1 to logic 0
Rising edge → change from logic 0 to logic 1
The choice of the signal depends on the specifics of the setup. For example, one setup for a falling edge is:
The input pin is kept at 24 V and it’s lowered to 0 V to produce the falling edge
The input pin is kept at 0 V and it’s elevated to 24 V for a short period of time. Letting it fall back down produces a falling edge that triggers the device
Whether the device is triggered by a falling edge, rising edge, or both is controlled by a parameter called Hardware Trigger Signal.
