User manual

Chapter 3 Software Overview
NI-DAQ User Manual for PC Compatibles 3-84 ni.com
Another type of gated pulse generation can be called retriggerable one-shot
pulse, where a signal pulse is produced in response to a hardware trigger.
To do this, call
CTR_Config
and specify edge gating. Connect your
trigger signal to the GATE input. Call
CTR_Square
to specify your pulse.
Subsequently, each edge sent to the GATE input produces one cycle of the
square wave.
Besides
CTR_Square
, you also can call
CTR_FOUT_Config
to generate
a square wave. The advantage of using
CTR_FOUT_Config
is that it
does not use a counter to generate the square wave. It uses a different
built-in feature of the counter/timer chip. However, unlike
CTR_Square
,
CTR_FOUT_Config
can only generate a square wave with a 50 percent
duty cycle.
NI-DAQ has a number of utility functions that give you more control over
the counters.
CTR_State
is for checking the logic level of any counter
output.
CTR_Reset
halts any operation on a counter and puts the counter
output to a known state.
CTR_Stop
and
CTR_Restart
stop and restart
any operation on a counter.
CTR_Simul_Op
simultaneously can start, stop,
and restart any number of counters. Also,
CTR_Simul_Op
simultaneously
can save all the current counter values to their hold registers, which you
can read later, one at a time. See Figure 3-30 on how to incorporate
CTR_Simul_Op
with other counter functions like
CTR_EvCount
and
CTR_Pulse
.