Good morning, 

I am currently encountering a problem with a CPU 315F-2PN/DP which equips one of our production lines. For several days, when we power up the line, the CPU remains stuck in STOP mode, indicated by a yellow light on.  Even after returning the button to the MRES or STOP then RUN position, the CPU does not go into RUN mode and the yellow indicator persists. It is necessary to cycle power to the line several times (2-3 times) before the CPU finally boots into RUN mode.  This unusual behavior worries me.

Could you help me identify the cause of this problem? 

Sincerely,

I understand, I'll check it out. Thanks for your help.