Modbus is a master-slave protocol when it is used over serial communication networks. This protection relay implements both the slave and master side of the protocol. Depending on the chosen physical serial interface it is possible to build multidrop networks or point-to-point communication connections.
Note: Modbus slave and Modbus master protocols are supported independently by the relay. Their availability depends on the options chosen when the device is ordered.
There can only be one Modbus Master unit on a Modbus serial network. The Modbus Master unit communicates with one Modbus Slave unit at a time. Normally, the master reads, or scans, data from the slaves cyclically. Each slave unit has a unique unit address, allowing the master to identify and communicate with the specific slave unit.
The Modbus Master protocol in this relay supports only the Modbus RTU link mode.