Using the PFI Trigger Line on a PXIe Chassis

Updated Nov 22, 2019

Reported In

Hardware

  • PXI Chassis

Software

  • LabVIEW

Driver

  • NI-DAQmx
  • NI-DCPower
  • NI-DMM
  • FlexRIO
  • NI-FGEN
  • NI-SCOPE

Issue Details

I have a PXIe card which I need to start using an external hardware trigger. I am using a PXI Express Chassis with the Timing and Synchronization Option like a PXIe-1095 or PXIe-1092, which have 4 PFI lines. Is there any way I can use these as my trigger inputs?

Solution

Some drivers like NI-DAQmx, NI-DCPower or FlexRIO allow pointing directly to the PFI lines in the chassis 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 option to point directly to the PFI lines in the chassis (like NI-DMM or NI-Scope, as of November 2019), you can use the method shown below to connect the PFI lines in the chassis 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 then into a blank LabVIEW VI block diagram. The shown code will be automatically created.

Additional Information

The DAQmx Signal Routing VI's can be used to route the signal of the trigger from the chassis PFIs 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. You can reference the PFI connector with the terminal name /[hostname]/PFIn where [hostname] is the chassis' name on NI MAX and n the number of the PFI you want to use.

The same syntax can be used in drivers that need the trigger source to be specified as a string, like FlexRIO.