PXIe-8822 timing jitter

[CSU_Chris]

I have been having a lot of issues with timing jitter with my PXIe-8822 running NI Linux Real-Time. To test this, I made this very simple loop that is supposed to run every 50 us. According to the iteration duration, this loop only takes 2 us or so to run so it should have no problem running deterministically at 50 us.

I set a stop condition if the loop iteration duration exceeds 55 us (>10% jitter). The loop always stops after a few minutes of running. In the attached screen shots you can see the timing jitter that is present even in this very simple test case.

Are there things I need to be doing with the PXIe-8822 to better ensure that timed loops run on time?

[ZYOng]

That periodic jitter looks like the Jitter on Chassis With Timing and Synchronization Upgrade I encountered years ago. However, PXIe-1088 does not have the T&S upgrade option.

Try Update PXI Chassis, Controller Firmware to the latest version (PXIe-8862/8842/8822 Firmware and Additional Drivers Download). 

[CSU_Chris]

Thanks for your suggestion, ZYOng. Sorry I didn't respond sooner, I was pulled onto another project. I updated the controller firmware as you suggested and tried again. I still see periodic timing jitter. I ran the same test again, where I set the loop to run at 50 us and stop if loop time exceeded 55 us. The code will still only run for a few minutes before timing exceeds 55 us.