Here is the system I have: Pentium 4, Windows XP, LabVIEW 8.2.1, 6250M Card
I need to perform nondestructive testing in which I use a hammer to generate an impulse and a set of sensors (up to 10 of them) to record the response. The measured response contains noise (random and high frequency). I remove the random noise by performing several tests and averaging the results. Because I average the results, I want the results to line up in time.
I line up the results in time by the following algorithm
- Start the VI and record to a buffer
- Start recording based on a trigger voltage and channel
- Record a defined number of pretrigger scans from the buffer (for each channel)
- Record a defined number of posttrigger scans (for all channels).
My old data acquisition VI was written in LabVIEW 6, but that doesn't work with M-series cards. I've been working on VI's with DAQmx, and have several that kind of work.
I can record one channel of data with triggering, the proper number of pretrigger scans, and the proper number of posttrigger scans or
I can record multiple channels of data with triggering but no pretrigger scans.
I looked at the example VI "Cont Acq&Graph Voltage-Analog SW Trigger.vi" but it doesn't quite work.
I have attached the VI that kind of works for me.