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Knowledge base

Official Modbus specification

When a Modbus address or function code is unclear, use the Modbus Application Protocol Specification from Modbus Organization as the primary source.

Original PDF

Modbus Application Protocol Specification V1.1b3.

Open on Modbus.org

Specifications page

Official Modbus Organization documentation page.

Open specs

FaScan practice

Translate 40001-style maps into function code and offset.

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FaScan does not mirror the full third-party PDF; it links to the official source.

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