L33ER major fault

Hi, guys..

So we had a problem with PLC AB L33ER ver 21.11 for compressor control panel.
After running well for 3 months, suddenly there was PLC fault shutdown signal.
When we checked it out, it was major fault code 061 (please see attachment).
So we cleared out the fault, download the program again and it worked again.
But after 24 hours, the same problem occured again.

Do you have any suggestion on this problem?

Thanks n regards,
Kardel

From this useful manual http://literature.rockwellautomation.com/idc/groups/literature/documents/pm/1756-pm014_-en-p.pdf it says the following for error 61.

Cause
1 61 For a controller with a memory card installed, the controller:
• Detected a non-recoverable fault.
• Wrote diagnostic information to the memory card.
• Cleared the project from memory.

Recovery Method
1. Clear the fault.
2. Download the project.
3. Change to Remote Run or Run mode.
If the fault persists, contact Rockwell Automation support.

Do you know if the plc is losing power when this happens?