FANUC Alarm SRVO-073 — SERVO CMAL alarm
Error- Hardware
- Pulsecoder (encoder)
- Controllers
- R-J3iB / R-30iA / R-30iB
- FANUC class
- SERVO2
- Hardware family
- FANUC Pulsecoder, backup battery and position loss alarms
Manufacturer wording — SERVO CMAL alarm(Group:%d Axis:%d)
The manual prints placeholders; your controller fills them in with the real group, axis or number.
FANUC SRVO-073 (“SERVO CMAL alarm”): The pulse coder might be faulty, or noise might be causing the pulse coder to malfunction. First check: Perform simple mastering and improve the shielding.
Updated 2026-10-22 · LogrobotLM reference
Description
The pulse coder might be faulty, or noise might be causing the pulse coder to malfunction.
Remedy
Perform simple mastering and improve the shielding.
Field diagnosis
The Pulsecoder is faulty or disturbed by electrical noise.
What to check
- Check the cabinet grounding and the connection of the shields to the ground plate; improve the grounding of the motor flange (especially on auxiliary axes).
- Then replace the Pulsecoder and redo the mastering.
- On some versions the code requires a power cycle.
- Note: CMAL followed by SRVO-075: the position is no longer established; jogging by one motor revolution re-establishes it.
Related codes
Indicative field information — the robot manufacturer's manual and safety procedures always prevail. Never bypass a safety device; apply lockout/tagout (LOTO) before any physical intervention. How this reference is built →