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Using the SMB Trigger Line on a PXI(e) Controller

Updated Feb 20, 2020

Reported In


  • PXI Controller


  • LabVIEW


  • NI-DAQmx
  • NI-DCPower
  • NI-DMM

Issue Details

I have a PXIe card which I need to start using an external hardware trigger. I don't have any other cards besides my PXIe controller which has a trigger SMB input. Is there any way I can use this as my trigger input?


Some drivers like NI-DAQmx and NI-DCPower allow pointing directly to the SMB trigger input in the controller (in this case a PXIe-8880) to trigger the card, as shown in the code snippet below.

If your are working with a card that uses a driver that returns an error when attempting this, or does not have an options to point directly to the SMB trigger input from the controller (like NI-DMM or NI-Scope, as of November 2019), you can use the method shown below to connect the controllers SMB input to the PXI Trigger Lines in the chassis backplane and point the card's trigger to the chosen PXI Trigger Line instead.

Note: the pictures in this article are code snippets. To use them, download them and drag them into a blank LabVIEW VI block diagram. The shown code will be automatically created.

Additional Information

As of PXI Platform Services 17.3, you can use the SMB terminals on NI PXI(e) controllers for trigger routing. This feature is only for Windows.

The trigger simply needs a short circuit or the release of a short circuit between the negative and positive polarities in order for falling or rising edge trigger to be detected.

The DAQmx Signal Routing VIs are the VIs that can be used to route the signal of the trigger from the controller to the backplane trigger line. From this location the cards within the PXI(e) Chassis can use the signal which comes through the trigger line. Users can reference the SMB connector with the terminal name /[hostname]/TRIG_SMB where [hostname] is the controller's name on the network.