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ErrorLib — Industrial Fault Code Library

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SRVO-073

CMAL alarm (Pulsecoder Abnormality)

Fanuc · R-30iB Mate + Mate Plus Robot

What does SRVO-073 mean?

This alarm (Group:i Axis:j) indicates that the Pulsecoder is likely abnormal or has malfunctioned due to electrical noise. This can lead to incorrect or unstable position feedback for the associated axis, causing control instability or position errors.

Common Causes

  • Pulsecoder communication anomaly (CMAL - Communication Abnormality).
  • Data transfer errors between the pulsecoder and servo controller.
  • Noise or interference affecting pulsecoder signals.
  • Faulty pulsecoder unit or servo drive communication interface.
  • Incorrect communication protocol settings or timing.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Check whether the connection of the controller earth is good, verifying the earth cable connection between the controller and robot connection cables securely to the grounding plate.

  2. 2

    Reinforce the earth of the motor flange (in case of Auxiliary axis).

  3. 3

    Reset the Pulse count for the affected axis.

  4. 4

    Replace the Pulsecoder for the affected axis.

  5. 5

    Replace the robot connection cable (RMP1, RM1, RP1) connected to the affected axis.

  6. 6

    Replace the internal cable of the robot for the Pulsecoder or motor of the affected axis.

Browse all codes in this manual (53)
Verified technical data. Last updated: April 2026

Related Faults

24EXTEmergency Stop Circuit 24V Fault24TTeach Pendant 24V FaultALM LED Blink (1:1)Broken Wire or Noise (Subsequent Unit)
Source: Fanuc R-30iB Mate + Mate Plus Robot
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