Pre trigger data acquisition with DMM

[srgray]

Hello all,

I'm trying to perform a waveform capture using my PXI-4072 DMM card. I'm using an external trigger to start the waveform capture. My question: Is there a way to capture data BEFORE the trigger occurs and have it included in the waveform? I've seen this capability on other cards (usually using some sort of circular buffer while waiting for the trigger).

Thanks,
Stephen

[Brooks_C]

Hello Stephen,

I noticed that this was a duplicate post after I made my response, but I agree with Nick F.  For the sake of keeping all of this information together please refer to this thread:  Pre-trigger waveform capture

It sounds like what you are looking for is a reference trigger to specify how many pre-trigger samples you want.  Unfortunately, if this is the case, there is not a built in VI that allows you to do this for the NI-DMM driver.  If you want to do this you’ll need to configure the DMM to continually acquire at a specified rate.  Then you’ll need a second data acquisition device to read in the trigger and then programmatically trigger the DMM acquisition in software to keep the correct data points.

This seems like a reasonable thing for the DMM driver to accommodate.  I will go ahead and submit a product suggestion and I encourage you to do the same.  To submit a product suggestion you can go to the Product Suggestion Center.

Have a good night!