Self-Test Fails When Multiple PXI-6683H Cards Are Present in PXI/MXI Systems

Updated Jun 16, 2026

Reported In

Hardware

  • PXI-6683H
  • PXI-6683

Driver

  • NI-Sync

Operating System

  • Linux

Issue Details

I am setting up an application with two NI PXIe-1095 chassis. One chassis contains a PXI controller running NI Linux Real-Time, and the second chassis contains a NI PXIe-8398 remote control module. I installed one NI PXI-6683H Synchronization Module in each chassis so I can synchronize data acquired across both chassis to meet application requirements.

NI-MAX Self-Test Fails on the second PXI-6683H I install in the PXI+MXI system, NI-MAX provides no additional context regarding the reason why the test failed as shown below:

 

If I leave only one PXI-6683H module in PXI+MXI system, Self-Test passes without errors. Upon testing the cards individually, both PXI-6683H modules pass the Self-Test.

Solution

This behavior is expected due to a limitation of the NI-Sync on Linux Real-Time and Linux Desktop operating systems.
 
NI-Sync does not support using two or more NI PXI-6683H modules in the same system, whether the modules are installed in the same chassis or in separate chassis connected through MXI. 
 
On a PXI/MXI configuration, the PXI controller treats the second NI PXIe-1095 chassis that contains the NI PXIe-8398 remote control module as an extension of the primary chassis. As a result, NI MAX detects both NI PXI-6683H modules as part of the same system, and Self-Test fails.
 
To work around this behavior:
  1. Remove the NI PXIe-8398 remote control module and install a PXI controller on the second chassis.
  2. Install one NI PXI-6683H module in each independently controlled chassis.
  3. Synchronize both chassis using IEEE-1588, IRIG-B or similar synchronization protocols.

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