FANUC
401 SERVO ALARM: VRDY OFF
서보 레디 신호 OFFWhat it means
The servo amplifier dropped its ready signal. Axes stop and the program halts.
Check first
- Write down the amplifier STATUS display first
- Check E-stop buttons and door interlock chain
- Measure 3-phase main supply
Common causes
- Emergency stop chain open
- Faulty MCC contactor
- Amplifier fault
- Main supply or DC link voltage
Field fixes
No field cases yet.