This program leverages the retrigger ability of counters to overcome the fact that start triggers for analog/digital acquisitions are not retriggerable.
The attached VI conducts 'retriggered' finite acquisitions on an analog signal. It does this by creating a retriggerable finite pulse train and using this finite pulse train as the sample clock for a continuous acquisition. Every time the trigger fires, a finite pulse train is generated which acts as the sample clock for the continuously acquiring analog input task. The analog input task therefore only returns samples according to the finite pulse train generated.
The trigger for this example can be any TTL signal: on-demand pulse or hardware timed pulse train.
LabVIEW 8.6 or compatible
DAQmx 8.7.2 or compatible
NI DAQ device with Analog Input and Counter/Timer
Steps to Implement or Execute Code
Select your device and analog input channel in the Channel Being Read on the front panel
Select your "Retriggerable Counter" for the sample clock output
Select the PFI line corresponding to the Retriggerable Counter
Select the Trigger Source
Specify your Finite Acquisition Parameters (Frequency & Samples Per Trigger) as desired
Run the VI
Additional Information or References
**This document has been updated to meet the current required format for the NI Code Exchange.**