Multiple PXI-6143 pretrigger problem

[boto]

Hi All,

I am running into some strange pretrigger problem on using multiple PXI-6143 cards and hoping you can give some help!

I am using 4 PXI-6143 boards in a PXI-1033 chassis to do 32-channel simultaneous analog input acquisition. I used the DAQmx functionality to configure a pretrigger task using reference digital trigger externally fed into a PFI line. The program will acquire those data and save into a TDMS file (through DAQmx Configure Logging.vi) and then finish. I found that the pretrigger works well if I only select channels from a single board (say Slot2 ai0:7, or Slot3 ai0:5, somthing like this). When I fire up the trigger, the program finishes almost right away. The program is basically configured using DAQmx utilities.

However, if I select channels from more than one board (say Slot2 ai0 + Slot3 ai0), no matter how many channels I selected, after firing up the trigger, the program will keep going for approximately the amount of time required for all pretrigger samples to be acquired, and then finish. So then in the resulting file the desired signals right before the pretrigger happens were not there.

This is very strange... Can anyone recommend a fix, please?

Thanks a lot!

[Knoxberry]

Hey Boto,

I would try posting this question to the PXI board as it is more of PXI related issue than a multifunction DAQ issue. In the meantime I will look into the issue and see if I can come up with some troubleshooting steps for you.

Best Regards,

[boto]

Thanks a lot Ian! I will try to post it there as well right now.

[John_P1]

You have posted to the right place...

See here.

Best Regards,