When using AI start with pretrigger scans, which terminals do I need for AI Read

[thatguy]

I am trying to acquire pretrigger scans, but the data is written to file as NaN. I think this may be a problem with the setting of the AI read vi. Do I need to use the AI Buffer Read vi? Which terminals must be used to read the data I want? (ie. conditional retrieval, read/search location, etc.) Thank you.

[Photon_Dan]

The NaN could be the result of a timeout. If you only want the pretrigger scans, simply use AI Read.vi and ask it to read the number of pretrigger scans you requested at AI Start.vi. There is a good example called "Acquire&Proc N Scans - Trig.vi" located in the ..../examples/DAQ/anlogin/anlogin.llb library.

Also, remember that the Alliance Members are ready and waiting to help. We do this stuff every day.

Daniel L. Press
PrimeTest Corp.
www.primetest.com

[thatguy]

I also want the data after the trigger. The program will give me the data after the trigger, but for the time it is running prior to the trigger, all there is is the NaN. The only problem seems to be the fact that it won't read the actual data from the buffer. I have attached my program, as well as one sample of data to show my problem. Anyone's suggestions/help is very much appreciated.