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ErrorLib — Industrial Fault Code Library

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291

External Pulse Axial Speed Exceeded

Fanuc · Alpha i series AC Servo Motor

What does 291 mean?

The speed of an axial movement specified by an external pulse has exceeded its upper limit. This alarm is active only when the EPEXA bit of parameter No.001 is set to 1, indicating an overspeed condition from external command.

Common Causes

  • Axial movement speed commanded by an external pulse exceeds the configured upper limit.
  • Incorrect magnification of the external pulse (parameters No.062 and No.063) leading to excessive commanded speed.
  • EPEXA bit of parameter No.001 is set to 1, enabling this speed limit check.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Check the speed value being specified by the external pulse signal.

  2. 2

    Verify the magnification settings of the external pulse using parameters No.062 and No.063.

Browse all codes in this manual (60)
Verified technical data. Last updated: April 2026

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000Power-Down Required Parameter011Zero Feedrate Specified013Maximum Feedrate Zero
Source: Fanuc Alpha i series AC Servo Motor
Open Manual (Page 223)Search more codes in this manual