Generating a Pulse
Using a counter to output pulses is called pulse generation. Some measurement devices can generate TTL pulses from the counter/timer of the device. The pulse is either low (starts high, pulses low, and returns high) or high (starts low, pulses high, and returns low). A pulse can be used as a clock signal, a gate, or a trigger for other measurements and generations.
Each pulse or pulse train consists of three parts:
- Initial Delay—The amount of time the output remains at the idle state before generating the pulse
- High Time—The amount of time the pulse is at a high level (5 V)
- Low Time—The amount of time the pulse is at a low level (0 V)
Using the DAQ Assistant, you can configure how long a pulse generated within a task remains at high level or low level.
The polarity of the pulse generation is controlled by Idle State. With Idle State set to Low, the pulse generation starts low for the Initial Delay, transitions high for the high time, and then transitions low for the low time. The high and low times are then repeated for the desired number of pulses. With Idle State set to High, the pulse generation starts high for the Initial Delay, transitions low for the low time, and then transitions high for the high time. The low and high times are then repeated for the desired number of pulses. In both cases, the output rests at Idle State after the generation completes.