Using SC Express channel for trigger

[GatorMech89]

Hi everyone,

 So I have what seems on the surface to be a relatively simple problem, but I have been struggling with it. I have a PXIe chassis and four PXIe-4331 bridge sensor modules. I want to use one of the channels from the module in slot 2 of the chassis as a trigger source (for example, this channel may be a load cell and it starts a load and strain acquisition task upon a certain load level). The trigger would begin a high speed acqusition phase for a certain duration and the task would return waveforms for all channels a certain number of milliseconds before the start trigger until a certain number of milliseconds after the end trigger. This would be extremely easy in Software Land but I'd like to keep my acquisition rate up around the 2kHz range so I'm stuck with hardware triggering and buffering.

 I was trying to figure out how to drive a PXI _TRIG line or other such trigger line for this purpose, but it seems as though the PXIe-4331 cannot do this. Can a virtual channel drive a PXI-TRIG? Has anyone dealt with this problem or does anyone have any suggestions?

Thanks,

Jordan

[Tori_W]

Hello Jordan!

Please take a look at the NI PXIe-4330/4331 User Manual for more information about triggering off PXIe-4331 signals using the TRIG lines. Start at page 2-30 for specific information on types of triggers you can use from your channels. Then look at page 3-1 for information on how to work with TRIG lines.

If you are already following this procedure and still running into problems, please answer the following questions:

1. Is the module in slot 2 a PXIe-4331? It is somewhat ambiguous in your initial question and I just want to verify.

2. What chassis are you using?

3. How are you creating your trigger and how are you routing it to your TRIG lines? What software (with version) are you using to do these things?

4. Is there a certain part of the procedure in the Manual that you are concerned about?

Thanks,

Tori Wooldridge

NI, Applications Engineer