analog triggering in labVIEW

[yephimeyz]

Hi everyone,

I am a college student beginning to learn labVIEW for my summer project and I have a huge issue understanding how to perform analog triggering in LabVIEW. I did  write a .Vi  which  should work,  but  it does not. Any help on this will be greatly appreciated.

The issue is this:

I have a video signal (an output of a photodiode array-128 elements hence 128 pulses) and i need to sample a single data point at the center of each pulse. I have a trigger signal which goes high at the center of each video pulse.  I wrote a .vi which uses a "for" loop to  perform single point sampling using the "start analog edge function" and my trigger signal. This runs, but  appears to be too slow to capture every pulse.

Is there a more efficient way to carry out fast single point sampling in labVIEW ? If so, can  someone point me in the right direction. I have been searching the forum for weeks to no avail.

I have attached my .vi file to this message.

Thanks a LOT for your help.

[mikeporter]

Set up the DAQ hardware to use an external sample clock, then use your center-of-the-pulse trigger signal to do the clocking. Doing it this way you'd set up a buffer for 128 samples and LV would read them in all at once. Check the examples, there may be one showing how to use an external sample clock.

Mike...