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ErrorLib — Industrial Fault Code Library

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#01

Unsupported Function Code

Omron · MX2 Inverter RS-485 Connection Guide

What does #01 mean?

The Destination Device (inverter) reported an unsupported function was specified in the Modbus command. This indicates that the Modbus function code sent by the master device is not recognized or implemented by the inverter, leading to command rejection. Such an error prevents the desired operation from being executed by the inverter.

Common Causes

  • The Modbus function code specified in the CMND instruction (S+1 lower byte) is not supported by the inverter's firmware.
  • An incorrect or deprecated function code was used in the Modbus-RTU communication command for the Destination Device.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Verify the Function code (S+1 lower byte) in the CMND instruction operand (e.g., #03 for Read from Holding Register).

  2. 2

    Refer to '8-5 Explanation of Each Function Code' in the Multi-function Compact Inverter MX2 Series Type V1 User’s Manual (Cat. No. I585) to confirm supported Modbus function codes for the inverter.

Browse all codes in this manual (15)
Verified technical data. Last updated: April 2026

Related Faults

#02Invalid Modbus Address#03Invalid Modbus Data Format#21Data Out of Inverter Range
Source: Omron MX2 Inverter RS-485 Connection Guide
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