MITSUBISHI pLC, alarm display ERROR

Error display
“[EPROR] LED scintillation”
When the equipment exceeds the specification, the circuit is not good, or there is abnormal noise, conductive foreign matter mixed into the cause of the changes in the contents of the program memory.
The LED will flash, the programmable controller STOP, and the output will change to OFF. In this case, please reconfirm the program and check it.
There are no conductive foreign bodies and high intensity noise sources.
“[ERROR] LED light”
(CPU) due to the mixing of conductive foreign matter inside the programmable controller or external abnormal noise, it results in runaway or over operation cycle.
200ms, WDT error, the LED lamp is bright, programmable controller STOP, and all outputs are OFF.
Power failure reset, if the programmable controller returns to normal, please check whether there is abnormal noise source, whether there is conductive foreign matter mixed.
In addition, please check whether there are third kinds of grounding according to the specifications and external wiring of the [4. power circuit.
The results of inspection should be checked according to the 8.1 item if there is a change in the LED light. If the LED still keeps the light state.
Please confirm that the program operation cycle is too long.
If all the checks are carried out, the light state of the [ERROR]LED can not be removed, and some kind of failure should be taken into consideration in the programmable controller.