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The Modbus protocol is a communications protocol that is based on a client-server architecture. It was created in 1979. In the industry, the Modbus has developed into a de facto standard since it is an open protocol.
Modbus allows connecting a server and several clients, usually via Ethernet. Three different operating modes are differentiated for data transmission: Modbus ASCII, RTU and TCP.
Each bus participant must have a unique address. In this case, the address 0 is reserved for a broadcast. Each participant may send messages via the bus.
Kollmorgen AKD Drive offers the TCP mode Modbus. TCP/IP packets are used to transmit the data. The TCP port 502 is reserved for Modbus TCP.