Modbus made it possible to connect an entire group of devices using only two wires on the controller. Modbus introduced the concept of data on the factory floor. It is the most pervasive communications protocol in industrial automation and is the most commonly available means of connecting industrial electronic devices. Modbus is an open standard, meaning that manufacturers can build it into their equipment without having to pay royalties. The early roots of Modicon started in 1968 with a core group of engineers led by Dick Morley that invented the first programmable logic controller. The Modbus serial communication protocol was developed by Modicon and published by the company in 1979 for use with its programmable logic controllers (PLCs). It is popular for remote applications that communicate over almost any means, including wired and cellular telephone, licensed and unlicensed radios, and satellite. Modbus is an extremely compact and flexible protocol that continues to prove it can be adapted for use in a wide range of applications and media. Originally intended for communications between programmable logic controllers (PLCs) and computers, it has become a de facto standard communication protocol for connecting a wide range of industrial electronic devices. In simple terms, Modbus is a method used for transmitting data over serial lines between electronic devices. Virtually any type of sensor and controller devices can be found that incorporate Modbus networking, including programmable logic controllers (PLCs), process controllers, process instruments, process sensors, PID controllers, motor drives, energy meters, Supervisory Control and Data Acquisition (SCADA) systems, programmable automation controllers (PACs), discrete sensors, valves, and many other embedded devices. Modbus has stood the test of time and is still being used in a wide range of applications, including industrial automation, process control, building automation, transportation, energy, and remote monitoring. The Modbus communications protocol is the networking granddaddy of the industry.

Modbus rtu master