SRVO-073: CMAL alarm (pulse coder noise/fault)
The encoder is misbehaving in a way that's either a real fault or electrical noise scrambling it - and FANUC's remedy list starts with grounding, which tells you noise is the frequent culprit.
What it means
The encoder is misbehaving in a way that's either a real fault or electrical noise scrambling it - and FANUC's remedy list starts with grounding, which tells you noise is the frequent culprit.
Common causes
Ranked by what technicians most often find, most likely first.
- Poor grounding letting noise corrupt the encoder (check the earth cable between controller and robot).
- Phantom alongside the SRVO-068/069/070 communication trio.
- Failed encoder, robot connection cable, or internal encoder/motor cable.
- On auxiliary axes: weak motor-flange grounding.
How to fix it
- Check the 068/069/070 trio in the history first.
- Verify the controller-to-robot earth connection is secure; on aux axes reinforce the motor flange ground.
- Then hardware in order: motor (re-master after), robot connection cable, internal robot cable.
- Recovery sequence after fixing the cause: PULSE RESET operation, then power cycle.
Quick facts
- Category
- Servo
- Affected series
- R-30iB; R-30iB Mate; R-30iB Plus; R-30iB Mate Plus
- Alarm family
- SRVO
Related codes
- SRVO-068DTERR alarm (pulse coder no response)
- SRVO-069CRCERR alarm (pulse coder data corrupt)
- SRVO-070STBERR alarm (pulse coder framing error)
- SRVO-072PMAL alarm (pulse coder fault)
- SRVO-074LDAL alarm (pulse coder LED broken)
- SRVO-071SPHAL alarm (feedback speed excess)
- SRVO-076Tip Stick Detection
- SRVO-078Servo param update