Mitsubishi Electric FR-A7NCA Instruction Manual page 39

(2) Measures at alarm occurrences
Alarm Indication Alarm Definition
Communication line
E.OP3
error
E.1, E.2, E.3 Option alarm
When alarms other than the above are displayed, refer to the inverter manual and remove the cause of the alarm.
Check the LED status of the option unit and remove the cause of the
alarm. (Refer to page 5 for LED indication status)
Inspect the master.
Check the connection between the inverter and option unit for poor
contact, etc. and remove the cause of the error.
Fit the communication option in the option connector 3.
INVERTER SETTING
Measures
4
31