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NI cDAQ-9172 User Guide and Specifications 60 ni.com
For counter output operations, you can use the arm start trigger to have start
trigger-like behavior. The arm start trigger can be used for synchronizing
multiple counter input and output tasks.
Start Trigger
For counter output operations, you can configure a start trigger to begin
a finite or continuous pulse generation. Once a continuous generation
triggers, the pulses continue to generate until you stop the operation in
software. For finite generations, the specified number of pulses is generated
and the generation stops unless you use the retriggerable attribute. When
you use this attribute, subsequent start triggers cause the generation to
restart.
When using a start trigger, the start trigger source routes to the
Counter n Gate signal input of the counter.
For counter input operations, the arm start trigger can imitate trigger-like
behavior.
Pause Trigger
You can use pause triggers in edge counting and continuous pulse
generation applications. For edge counting acquisitions, the counter stops
counting edges while the external trigger signal is low and resumes when
the signal goes high or vice versa. For continuous pulse generations, the
counter stops generating pulses while the external trigger signal is low and
resumes when the signal goes high or vice versa.
When using a pause trigger, the pause trigger source routes to the
Counter n Gate signal input of the counter.
Other Counter Features
Cascading Counters
You can internally route the Counter n Internal Output and Counter n TC
signals of each counter to the Gate inputs of the other counter. By cascading
two counters together, you can effectively create a 64-bit counter. By
cascading counters, you also can enable other applications. For example,
to improve the accuracy of frequency measurements, use reciprocal
frequency measurement, as described in the Method 3—Measure Large
Range of Frequencies Using Two Counters section.
Counter Filters
You can enable a programmable debouncing filter on each PFI signal.
When the filters are enabled, the NI cDAQ-9172 chassis samples the input