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ErrorLib — Industrial Fault Code Library

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Er1

Write disable error

Mitsubishi Electric · Mitsubishi FR-E800 Variable Frequency Drive

What does Er1 mean?

This error occurs if a parameter setting was attempted while Pr.77 (Parameter write selection) disables write operations, if frequency jump ranges (Pr.31 to Pr.36) overlap, or if communication between the PU (Parameter Unit) and the inverter is abnormal. It indicates an issue preventing parameter modification or a communication problem.

Common Causes

  • Attempt to write to a protected parameter memory location.
  • Parameter write disabled via a system setting (e.g., P1-01=0).
  • Hardware fault preventing modification of non-volatile memory.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Check the setting of Pr.77 (Parameter write selection) to ensure parameter writing is enabled.

  2. 2

    Review and correct any overlapping settings in Pr.31 to Pr.36 (frequency jump parameters).

  3. 3

    Check the physical connection between the PU and the inverter for proper communication.

Browse all codes in this manual (55)
Verified technical data. Last updated: April 2026

Related Faults

CFContinuous operation during communication faultDIPDuplicate IP addressE.1Option Fault / Internal Contact Failure
Source: Mitsubishi FR-E800 Variable Frequency Drive
View Official PDFSearch more codes in this manual