WHITEPAPER: Introduction to Modbus TCP/IP

Introduction to Modbus TCP/IP

The following information describes the operation of Modbus TCP/IP as it relates to Acromag Series 900EN-40xx I/O modules. Acromag manufactures a line of I/O modules that support Modbus over RS485, and Modbus over Ethernet.

The Modbus protocol was developed in 1979 by Modicon, Incorporated, for industrial automation systems and Modicon programmable controllers.

It has since become an industry standard method for the transfer of discrete/analog I/O information and register data between industrial control and monitoring devices.

Modbus is now a widely-accepted, open, public-domain protocol that requires a license, but does not require royalty payment to its owner.