Overview – Micromod MOD: MODBUS RTU Communications Guide User Manual
Page 5
MODBUS RTU
COMUNICATIONS GUIDE
1
OVERVIEW
MODBUS RTU is a non-proprietary serial communications protocol that is widely used in the process control
industry. The protocol was developed by Modicon for PLC communications and later released for public use.
This protocol is available in all major Human Machine Interface (HMI) software packages and terminals. Many
of the major controller and PLC manufacturers also offer MODBUS protocol as a standard or optional protocol
in their instrumentation.
The hardware over which MODBUS RTU communications are performed is not defined by the protocol.
MODBUS RTU is supported on RS-232, RS-422, RS-485, Ethernet and other electrical standards.
It should be noted that MODBUS RTU, MODBUS ASCII and MODBUS Plus are unique communication
formats, and are not compatible with each other. This document will discuss MODBUS RTU only.