Robotics in Manufacturing
SRVO-066

SRVO-066: CSAL alarm (pulse coder checksum)

The encoder's internal ROM failed its checksum - the pulse coder's firmware data is corrupt.

What it means

The encoder's internal ROM failed its checksum - the pulse coder's firmware data is corrupt. Barring the phantom-alarm case, this is a dead encoder, which on these motors means motor replacement.

Common causes

Ranked by what technicians most often find, most likely first.

  1. Pulse coder ROM failure.
  2. Phantom alongside SRVO-068/069/070 communication alarms - check those first.

How to fix it

  1. If SRVO-068/069/070 appear together with it, work those remedies before condemning the encoder.
  2. Otherwise replace the motor, then perform mastering. Power-cycle required to clear.

Quick facts

Category
Servo
Affected series
R-30iB; R-30iB Mate; R-30iB Plus; R-30iB Mate Plus
Alarm family
SRVO

Related codes

Verified against FANUC documentation (B-83284EN-1).Last reviewed: 2026-07-09.Editorial process