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ErrorLib — Industrial Fault Code Library

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Alarm 6

Software Disconnection (α Pulse Coder)

Fanuc · Alpha i Series Servo Amplifier

What does Alarm 6 mean?

This alarm is issued when the absolute position data sent from the built-in α pulse coder cannot be synchronized with the phase data.

Common Causes

  • The alpha pulse coder (encoder) has lost its signal.
  • Software error related to the alpha pulse coder interface.
  • Encoder is not transmitting valid data.
  • Faulty connection or internal encoder issue affecting the alpha signal.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Turn off the NC (Numerical Control) power.

  2. 2

    Remove the pulse coder cable.

  3. 3

    Attach the pulse coder cable again securely.

  4. 4

    If this alarm is issued again after re-attaching the cable, replace the pulse coder.

Browse all codes in this manual (101)
Verified technical data. Last updated: April 2026

Related Faults

0233Velocity Pulse Count Exceeded0243Position Pulse Count Exceeded0434Velocity Loop Integral Gain Overflow
Source: Fanuc Alpha i Series Servo Amplifier
Open Manual (Page 45)Search more codes in this manual