LogrobotLM

LogrobotLM — AI fault diagnosis for ABB · KUKA · FANUC robots. It reads your robot backup in your browser (never uploaded) and pinpoints the fault. Try it free →

FANUC Alarm SRVO-066 — SERVO CSAL alarm

Error
Hardware
Pulsecoder (encoder)
Controllers
R-J3iB / R-30iA
FANUC class
SERVO2
Hardware family
FANUC Pulsecoder, backup battery and position loss alarms

Manufacturer wording — SERVO CSAL alarm(Group:%d Axis:%d)
The manual prints placeholders; your controller fills them in with the real group, axis or number.

FANUC SRVO-066 (“SERVO CSAL alarm”): The pulse coder ROM checksum data is abnormal. First check: If this alarm occurs along with a SRVO-068 DTERR, SRVO-069 CRCERR, or SRVO070 STBERR, disregard this alarm and refer to the other three alarm remedies. Likely part: Pulsecoder (Pulsecoder (motor encoder)).

Updated 2026-10-22 · LogrobotLM reference

Description

The pulse coder ROM checksum data is abnormal.

Remedy

If this alarm occurs along with a SRVO-068 DTERR, SRVO-069 CRCERR, or SRVO070 STBERR, disregard this alarm and refer to the other three alarm remedies. Replace the pulse coder or motor and master the robot.

Field diagnosis

The checksum of the Pulsecoder internal memory is wrong.

What to check

  • If DTERR, CRCERR or STBERR accompany it, ignore CSAL and deal with the link.
  • Otherwise replace the Pulsecoder (or the motor) and redo the mastering.
  • Note: R-J3iB/R-30iA generation.
  • Diagnostic sequence “Encoder link, not the encoder”: The three codes 068/069/070 appear together, sometimes with PHAL (064) or CSAL (066): the encoder serial link is at fault, and the encoder codes accompanying them are symptoms. Robot connection cable connectors at both ends, shield grounding, robot connection cable, robot internal cable; encoder and amplifier only after that. Do not replace the motor first.

Part to check / replace

FANUC SRVO-066 points to the hardware below — start here before ordering.

Tap a part for every code that points to it — and verify the exact variant for your controller before ordering.

Related codes

SRVO-068SERVO DTERR alarmSRVO-069SERVO CRCERR alarmSRVO-070SERVO STBERR alarmSRVO-072SERVO PMAL alarmSRVO-064SERVO PHAL alarmSRVO-065WARN BLAL alarm

Same hardware involved

SRVO-038PulsecoderSRVO-061PulsecoderSRVO-063PulsecoderSRVO-071Pulsecoder

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 →