Modbus is a serial communications protocol published by Modicon and generally used with PLCs(programmable logic controllers). It has now become a factory standard for communications protocols in industry, and is the most commonly used means of communicating industrial devices. The main reasons for the extensive use of Modbus over other communications protocols are: It is open source protocol and it’s free. It is simple to understand, easy to implement. It moves raw bits or words without placing many restrictions on vendors Modbus allows for serial communication between many third party devices connected to the same network, for e.g. a system that measures temperature and humidity and communicates the results to a computer or number of VFDs communicating to PLC over a single Modbus serial line. Modbus is often used to connect a supervisory computer with a remote terminal unit (RTU) in supervisory control and data acquisition (SCADA) systems. Modbus ...