Modbus Function Not Recognized

What does 1 mean?

The Modbus slave device did not recognize or support the requested function code. This indicates the master is attempting an operation not implemented by the slave's Modbus protocol. Unresolved, this prevents the master from controlling or reading the slave using that specific function.

Complete Troubleshooting Guide

1. 1

   Verify the Modbus function code in the master's request against the slave device's Modbus communication manual.

2. 2

   Ensure the slave device firmware supports the requested function.

3. 3

   Check for any configuration settings on the slave device that might disable certain Modbus functions.