FANUC
300 APC ALARM: NEED REF RETURN
원점 복귀 필요 (APC)What it means
The absolute encoder lost its reference position. Usually a battery issue.
Check first
- Replace battery with power ON and machine in E-stop (trained staff only)
- Re-establish reference after replacement
- Check whether BLAL warnings were ignored
Common causes
- Encoder battery discharged
- Battery cable disconnected
- Axis moved with power off
Field fixes
No field cases yet.