Modbus RTU is a serial communications protocol published by Modicon in 1979 for use with its programmable logic controllers (PLCs).
Modbus RTU
It has become a de facto standard communications protocol in industry, and is now the most commonly available means of connecting industrial electronic devices.
The main reasons for the extensive use of Modbus over other communications protocols are: It is openly published and royalty-free, Relatively easy industrial network to deploy and it moves raw bits or words without placing many restrictions on vendors.
Modbus allows for communication between many devices connected to the same network, for example a system that measures temperature and humidity and communicates the results to a computer.
Modbus is often used to connect a supervisory computer with a remote terminal unit (RTU) in supervisory control and data acquisition (SCADA) systems.