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ErrorLib — Industrial Fault Code Library

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1A4FH

Mixed Axis Program Simultaneous Start Forbidden

Mitsubishi Electric · MELSEC iQ-R Motion Controller

What does 1A4FH mean?

This minor error occurs when attempting to execute a simultaneous start instruction (START) that includes a mix of real axis programs and command generation axis programs. The system does not support mixed program starts, and this action will prevent the control from initiating.

Common Causes

  • Attempted simultaneous start (START instruction) with a combination of real axis programs and command generation axis programs.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Separate the real axis programs and command generation axis programs.

  2. 2

    Execute simultaneous start instructions only with programs of the same axis type (either all real axis or all command generation axis).

Browse all codes in this manual (19)
Verified technical data. Last updated: April 2026

Related Faults

0BD2HSynchronous Encoder Axis Speed Monitor Range Exceeded19EAHCommand Generation Axis Length Per Cycle Invalid1A31HCommand Generation Axis Positioning Address Out of Range
Source: Mitsubishi Electric MELSEC iQ-R Motion Controller
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