Mitsubishi Electric MELSEC Q Series Reference Manual page 566

(2) When a programming tool connected station is faulty
Control station
No.1
Selected
Normal
station
station
No.4
564
Normal station
No.2
Normal station
No.3
Select the own station.
An error has occurred in the station No.4.
Click the error details button.
The Error Factor field indicates that a CPU module stop error has occurred.
Take corrective actions according to the troubleshooting.