64 channel 1450 Hz data logging with PCI-6033E card, on-line averaging and viewing the raw and averaged signal in CWGraphs.

Question

I'm acquiring 64 channels at sampling rate of about 1450kHz continuously and showing the data second by second in a CWGraph. Now, I would like to add an on-line averaging for all of those 64 channels and show it in another CWGraph. The averaging should occur with respect of external trigger and the sample should consist of about 100ms prestimulus and 500ms poststimulus period. Has anybody been handling this sort of things? How it's solved with ComponentWorks and Visual Basic?
I'm using double Pentium 700MHz processors and NI-DAQ PCI-6033E card.

Answer 1

1. To get started with external triggering check out the examples in the Triggering folder that install with CW under MeasurementStudio\VB\Samples\DAQ\Triggering.
2. Create a prestimulus buffer that always contains the latest 100 ms of data. Just modify the CWAI1_AcquiredData event to transfer ScaledData (the data acquired) to your prestimulus buffer. See how there will always be a prestimulus buffer of data regardless of trigger state?
3. On the trigger, you can use the same CWAI1_AcquiredData event to route the data into poststimulus buffer and average the 2.
I see something like this:
if no trigger
100 ms of data to prestimulus buffer
if trigger
500 ms of data to poststimulus buffer
averaging and display function
reset trigger and buffers
good luck
ben schulte
application engineer
national instruments
www.ni.com/ask