Reference Clock Synchronization with the PXIe-6535

Updated Oct 18, 2022

Reported In


  • PXIe-6535


  • LabVIEW


  • NI-DAQmx

Issue Details

I am trying to set up reference clock synchronization with my PXIe-6535 to do synchronized digital output, but my DAQmx Timing Property Node in LabVIEW does not show the Reference Clock:Source property as an option. Why does this property not appear and how can I set up reference clock synchronization on my PXIe-6535?


DAQmx Property Nodes by default only show supported properties for devices in your system. This implicitly means that reference clock synchronization is not supported by the PXIe-6535. This can also be verified by looking at the device routes in NI MAX, and seeing that PXI_Clk10 or PXIe_Clk100 are not available device routes.

An alternative to reference clock synchronization is to export the sample clock from the PXIe-6535 or another module (the master device) onto a PXI trigger line, and then route the slave PXIe-6535's sample clock to that line. Observing the device routes available for the PXIe-6535, the digital output sample clock (/DO/SampleClock) only can route to PXI_Trig7.

Here is a LabVIEW VI example that shows a basic sample clock synchronization. Note that you do not need to configure a start trigger because sharing a clock implicitly synchronizes the first sample of each module.