Software triggering with multi-channel voltage measurement

[Ian_C]

I am using Labview Express 7.0 and I have am trying to acquire data for 64 channels from NI's PCI607E card.

I sample at about 20 Khz and collect about 2000 samples. Currently I am using reference anlog trigger. It works fine right now. But I would like to chenge the triggering to a software type.

I am trying to add up the amplitudes of my 64 channles of signals (amplitude wise) and taking that summed signal to trigger the DAQ card to commence writing the data into a data file.

How can I get this going?

[Zvezdana S.]

Ian,
If you just need to check for summed signal value to start writing to a file, then put the code for writing in a case structure. When the summed signal is >= to a certaing value, then enter the case in the case structure that will start writing to a file.
Zvezdana S.

[Ian_C]

Hi Zvezdana,

I would like to trigger file writing when the summed amplitude exceeds a certain threshold value (above noise value). However I do not know when in time, this threshold has been attained. How do I code that up in Labview?

The other question is, how do I code this up in a case structure?

Ian