HELP!!!What is TIME LIMIT parameter in triggered acquisition???

[Giulia]

Suppose I have random noise(zero value). Sometimes there is something over a threshold (say 0.5). I want to run the acquisition and getting data only if threshold condition is satisfied. when this case happens, I want to get a fixed number of pre-trigger and post-trigger scans. After the requested data are collected, the system should get a "pause", waiting for the next over-threshold event without acquisition (that is, waiting for the next trigger). Help me, please!

[Jeremy Braden]

I am a lot rusty on my daq. I think this is what you need.
Acquire Analog Input Data Using a Software Analog Trigger

You may want to post to the daq forum. I highly recommend searching NI's advanced search page for example programs.

[Giulia]

thank u for your help, but the vi you suggested doesn't work. It always gets time out. Does time out mean also that time limit has exceed, that is trigger has not occurred becuse signal is too fast and acquisition rate is too slow? More over,what I want is to write data on file, just the exact number I need.

[Nirmal_Sharma]

Hi,

I think, try giving -1 to Time limit parameter in AI read Vi or give the maximum time limit not to occur the time out operation.

See the example program at below mentioned path in your computer:
C:\Program Files\National Instruments\LabVIEW 7.0\examples\DAQ\anlogin\anlogin.llb\Cont Acq&Graph (buffered) Hard A-Trig.vi.

If u r not able to find, open LV->goto Find examples-> Hardware Input and Output -> Traditional DAQ -> Analog Input -> General -> Cont Acq & Graph (Buffered) Hard A-Trig.vi.

Hope this helps. Your feedbacks are welcome.

Best Regards,
Nirmal Sharma