When A "Fatal Error Occurred" Message Appears - Mitsubishi FX3UC SERIES User Manual

FX Series Programmable Controllers
3UC
User's Manual - Hardware Edition

10.22.1 When a "Fatal error occurred" message appears

Operation is possible with the "Level C" or "Level B" entry code function restrictions.
However, the system is probably in one of the statuses described below. Check these statuses in the order
shown below, and take the appropriate corrective action.
1. Perform an error check at the display module, and if an error is active, take the appropriate
corrective action.
If a program error is active:
The fatal error was probably activated due to a program error.
Use the programming tool to correct the program.
If no program error is active:
There may be a problem with the PLC's memory content. Perform the following procedure.
1) Use the programming tool to perform a program memory all-clear.
2) Rewrite the program.
3) Stop the PLC, turn the power ON, display the "PLC Status (1/3)" screen and check to refer to if the "Fatal
error occurred" message appears.
- If the "Fatal error occurred" message appears, perform the corrective action described at item "2" below.
- If the "Fatal error occurred" message does not appear, set the PLC to a RUN state, then check again if
the message appears.
If the message appears, a watchdog timer error has probably occurred. In this case, the program should
be re-examined.
2. If the "Fatal error occurred" message still appears after performing the corrective actions
described in item 1 above, perform the following procedure to check for symptom changes.
Turn the power OFF and disconnect all extension devices.
(extension connectors, extension cables, and expansion board connectors)
Turn the power ON again at the main unit, display the "PLC Status (1/3)" screen again, and check if
the "Fatal error occurred" message appears.
1) If the "Fatal error occurred" message appears:
The main unit hardware may have failed. Contact your local Mitsubishi Electric distributor.
2) If the "Fatal error occurred" message does not appear:
Turn the power OFF, connect the extension devices, then operate the system again to check for errors.
If the problem persists, there may be main unit or extension device hardware failure. Contact your local
Mitsubishi Electric distributor.
→ Refer to Section 10.7 for the error check procedure.
→ Refer to Subsection 12.6.4 for error codes and corrective actions.
→ Refer to Subsection 12.5.3 for watchdog timer error corrective actions.
→ Refer to Subsection 12.5.3 for watchdog timer error corrective actions.
10 Display Module (Only FX3UC-32MT-LT)
10.22 Operation Error Messages & Corrective Actions
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