Problem

Unit identifier 0 is ambiguous

Unit identifier zero has transport and tool-specific behavior and can represent broadcast behavior in serial contexts.

Why it matters

A node-red-contrib-modbus issue records inconsistent Unit ID 0 validation. Tool documentation also exposes Unit ID 0 behavior, so generated read workflows must not silently choose it.

What to do

Sources

• node-red-contrib-modbus #274 github.com
• Witte Modbus Poll documentation modbustools.com