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ErrorLib — Industrial Fault Code Library

Disclaimer: ErrorLib is an independent technical reference tool. While we aim for accuracy, always verify with the manufacturer’s official service manuals before performing maintenance on industrial equipment. ErrorLib is not affiliated with the brands listed.

511

Negative Soft Stroke Limit Exceeded

Fanuc · Alpha i series AC Servo Motor

What does 511 mean?

The machine has exceeded its negative soft stroke limit, a software-defined boundary. This suggests improper parameter configuration for soft limits (No.143) or an invalid motion command, leading to an unexpected stop.

Common Causes

  • Appropriate values have not been specified for parameter No.143
  • An invalid move command has been specified

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Check whether appropriate values have been specified for parameter No.143

  2. 2

    Check whether a valid move command is specified

  3. 3

    Move the tool in the opposite direction in jog mode, then perform a reset

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

Related Faults

000Power-Down Required Parameter011Zero Feedrate Specified013Maximum Feedrate Zero
Source: Fanuc Alpha i series AC Servo Motor
Open Manual (Page 230)Search more codes in this manual