302

Serial Pulse Coder Communication Error (STBER)

Fanuc · Alpha i series AC Servo Motor

What does 302 mean?

A communication error (STBER) was detected for the serial pulse coder, suggesting a problem with data synchronization or framing during serial communication. This can be due to cable issues, faulty components, or noise.

Common Causes

  • Discontinuity or damage in the serial pulse coder signal cable.
  • Defective serial pulse coder.
  • Defective servo amplifier module.
  • External electrical noise interfering with serial communication.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Check the continuity and integrity of the serial pulse coder signal cable.

  2. 2

    If the cable is verified as normal, replace the pulse coder or the servo amplifier module.

  3. 3

    Implement noise reduction measures as described in the 'Descriptions' chapter on noise.

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Verified technical data. Last updated: March 2026

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Source: Fanuc Alpha i series AC Servo Motor