Synchronizing PXI Modules Using IRIG-B Protocol in LabVIEW

Updated Jan 2, 2024



  • PXI-6683
  • PXI-6682


  • LabVIEW


  • NI-Sync

NI-Sync driver allows synchronization through different Time Reference Protocols. One of them is the IRIG-B timing protocol. 

This guide explains how to synchronize your PXI cards using an IRIG-B timing protocol in LabVIEW using the NI-Sync driver API, and a PXI Timing and Synchronization Module, like the PXI-6682 or PXI-6683. 

1. Bring the IRIG-B signal on the PXI-668x PFI connector.
2. Set the PXI-668x time reference to either IRIG-B DC or IRIG-B AM depending on the IRIG-B signal.
  • To do this, you can check the LabVIEW example "Set Time". Located in LabVIEW >> Help >> Find Examples >> Hardware Input and Output >> Timing and Synchronization >> Time-based >> Set Time
3. Route the PXI-668x onboard oscillator to the PXI-668x clock-out connector (this can be done either in the code with the "NI Sync Connect Clock Terminals" or in NI MAX):
NI-Sync Connect Clock.png
4. Physically cable the clock-out connector to the chassis 10MHz IN port of the chassis
  • This is chassis dependent. The chassis must have a 10MHz IN port. As most of the PXI-668x cards have hybrid PXI connectors, there is no way to route this signal internally through the chassis. 
5. Set the modules you want to synchronize to use the 10MHz chassis backplane clock as a reference, using the corresponding function of their driver API.