Chapter 9

Counters

Figure 9-23shows a generation of a pulse with a pulse delay of four and a pulse width of three (using the rising edge of Source).

GATE (Start Trigger)

SOURCE

OUT

Figure 9-23.Single Pulse Generation with Start Trigger

Retriggerable Single Pulse Generation

The counter can output a single pulse in response to each pulse on a hardware Start Trigger signal. The pulses appear on the Counter n Internal Output signal of the counter.

You can route the Start Trigger signal to the Gate input of the counter. You can specify a delay from the Start Trigger to the beginning of each pulse. You also can specify the pulse width. The delay and pulse width are measured in terms of a number of active edges of the Source input.

The counter ignores the Gate input while a pulse generation is in progress. After the pulse generation is finished, the counter waits for another Start Trigger signal to begin another pulse generation.

Figure 9-24shows a generation of two pulses with a pulse delay of five and a pulse width of three (using the rising edge of Source).

GATE (Start Trigger)

SOURCE

OUT

Figure 9-24.Retriggerable Single Pulse Generation

For information about connecting counter signals, refer to the Default Counter/Timer Pinouts section.

© National Instruments Corporation

9-21

NI USB-621x User Manual