Modbus is a communication protocol developed by the Modicon company in the 1970’s. Originally it was used for communication in PLCs and RTU devices. Later on the Modbus protocol was used in a variety of different device applications. Today the Modbus protocol is mainly used over serial communication networks and Ethernet.
The Modbus serial communication and the Ethernet-based Modbus TCP/IP communication in this protection relay follow the specifications maintained by Modbus Organization.
Note: Modbus communication reference guides are downloadable from Technical Resources at www.modbus.org.