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Overview
This program leverages the retrigger ability of counters to overcome the fact that start triggers for analog/digital acquisitions are not retriggerable.
Description
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.
Requirements
Software
Hardware
Steps to Implement or Execute Code
Additional Information or References
VI Snippet
**This document has been updated to meet the current required format for the NI Code Exchange.**
Example code from the Example Code Exchange in the NI Community is licensed with the MIT license.
thanks for posting! could you rename your attachment to include the LabVIEW version? "_lvXX.vi" would be fine.
Hi ,
How can I modify this VI to generate pulses using the counter in time units? I want to leave it high for 3 s and low for 5 seconds and trigger the data acquisition every high time ?
On the first functional block (DAQmx Create Virtual Channel) you should be able to select CO Pulse Time from the drop down. From this you should now have access to the low and high time inputs to the Counter Output VI where you can select how long you will stay low and how long you will stay high.
PS if this does not work - try calling NI Support @ 866-275-6964.
Thank you so much.