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
Separate the real axis programs and command generation axis programs.
- 2
Execute simultaneous start instructions only with programs of the same axis type (either all real axis or all command generation axis).
Verified technical data. Last updated: March 2026
Related Faults
Source: Mitsubishi Electric MELSEC iQ-R Motion Controller