SP0139

Pulse Error Alarm

Fanuc · Alpha i Series AC Servo Motor and Spindle

What does SP0139 mean?

An error occurred in the interpolation circuit of the spindle control system. This typically indicates an issue with the feedback signal processing, leading to inaccurate position or speed control.

Common Causes

  • Incorrect or missing pulse signal from an encoder or other pulse-generating device.
  • Encoder damage or misalignment causing intermittent pulse output.
  • Noise or electrical interference affecting the pulse signal integrity.
  • Pulse counting error due to excessive speed or data rate.
  • Parameter settings for pulse input (e.g., P4-xx) are incorrect.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Verify the integrity of the pulsecoder feedback cable (e.g., K22 for SV, K16/K97 for SP).

  2. 2

    Check for electrical noise interference on the feedback lines.

  3. 3

    Inspect the pulsecoder for physical damage or misalignment.

  4. 4

    If the sensor head was moved, perform interpolation error learning according to Subsection 11.2.3.9.

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Verified technical data. Last updated: March 2026

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Source: Fanuc Alpha i Series AC Servo Motor and Spindle