L63 Losing its program

[hmiman 1]

Hi, I am experiencing an issue with an L63 controller going into a major fault and losing its program. Once this happens, you have to clear the fault with the keyswitch on the controller and then download. It doesn't seem possible to go online to look at the major fault code. This happens with multiple replacement processors, a new backplane, new power suppy and a good battery. The power also comes from UPS. Is there any part of the code that can cause a controller to do this? All the obvious checks have been done. Please help,

[BobLfoot 301]

Two quick thoughts. 1. Is the L63 the only thing on the UPS? or does it power I/O. 2. How well grounded is this panel and in what type of environment?

[rammin48 1]

Had a problem once like this. When they installed the cabinet and drilled the holes in the enclosure the electrician did not cover the PLC. The PLC and cards had metal shavings inside the cards. I had to blow all of the cards out and the problem went away. Something was either loading the power supply internally, down in a way that defeated any battery backup or UPS.

[Eddie Willers 2]

I recommend contacting RA Tech Support directly if you are experiencing a controller major fault that you cannot diagnose. Is the "OK" LED flashing red, or solid red ? Flashing red means a recoverable major fault, solid red is a nonrecoverable fault. If you can clear the fault with the keyswitch, it sounds like a recoverable major fault. That sort of thing can be caused by a programming error, but should not clear the user program. That's what is really happening; the controller isn't forgetting or losing the program, it is intentionally clearing it because it cannot run in its current state because it is corrupted or the program execution cannot logically continue. If the operating system has actually crashed, you can get a "dump file" via the serial port. RA Tech support provides the fault dump reading tool. Do you have a fault routine configured in the controller ?