PXI_CLK10 Disciplining With a Time Reference Across Multiple PXI Chassis

Updated Mar 8, 2023

Reported In


  • PXI-6683
  • PXI-6682
  • PXI-1042
  • PXIe-6674T


  • NI-Sync

Issue Details

  • I would like to synchronize the PXI reference clock (PXI_CLK10) on multiple PXI chassis to a time reference such as GPS, IRIG-B, or IEEE 1588. How can I do this?
  • I want to use the PXI-6683 PXI_CLK10_IN as the 10 MHz PXI backplane clock. When I open up the panel in Max to configure this I do not see the terminals to route this clock. How do I route the 6683's GPS disciplined clock to be the PXI backplane clock? 


If instead of using Time Reference like GPS, IRIG-B, or IEEE 1588, you want to share a reference clock between the chassis, refer to Synchronizing the 10 MHz Reference Clock on Multiple PXI/PXIe Chassis.

Synchronizing a Single Chassis to a Time Reference

  1. One option for synchronizing a PXIe chassis to a time reference is to use the NI PXI-6683 timing and synchronization module. This board has an onboard 10 MHz TCXO that can be disciplined to an external time reference such as GPS, IEEE 1588, or IRIG-B. See the Configuring GPS Synchronization with the NI PXI-668x Timing and Synchronization Module Tutorial for information on how to configure this system.

​Expanding the Synchronization to Multiple Chassis

  1. In general, when synchronizing multiple PXI or PXIe chassis you will have one master chassis and multiple slave chassis. The master chassis needs to be setup as described above. In general, it is also recommended that you set up your slave chassis in the same manner. However, if you do not have the cards available, the system can be configured in the default master/slave configuration with the full set of hardware being only in the master chassis.

Additional Information

  • If you have a PXIe chassis you will require the PXI-6683H. When using method 1, you will need to connect a cable between the CLKOUT connector on the PXI-6683H and a 10MHz Ref In connector on the chassis. Consult your chassis manual before selecting this approach to verify that your chassis has a 10MHz Ref In connector.
  • The PXI-6682H does not have the ability to do single-board disciplining, and cannot be used in method 1.
  • When following the instructions in the Configuring GPS Synchronization with the NI PXI-668x Timing and Synchronization Module Tutorial , you can enter the source and destination strings even if they do not appear in the drop down.