Status Light Blinks 4 Times on Real Time cDAQ Controller

Updated Jul 15, 2018

Reported In


  • cDAQ-9137

Issue Details

The status light on my Real Time cDAQ controller is blinking 4 times. The user manual says the following about this situation:

The software has crashed twice without rebooting or cycling power between crashes. This usually occurs when the controller runs out of memory. Review your RT VI and check the memory usage. Modify the VI as necessary to solve the memory usage issue


First, verify the memory usage of your application using NI Distributed System Manager. If your target is running out of memory, you'll need to either uninstall unnecessary software or change your program to be more lightweight.

If your memory usage is normal, then the problem could be a corrupt software installation. Reboot your controller into safe mode by holding the Reset Button for 5 seconds. The status light should now blink in groups of 3. You can now uninstall software from your target using NI MAX. Once the uninstall is complete, reboot your controller and try to connect again.

If the controller still fails to connect, then the error likely exists on the operating system itself. This can be fixed by reformatting the target. Instructions for this can be found in the article How Do I Format My Real-Time Target and Reinstall the Software?


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