Industrial Ethernet is the name given to the use of the Ethernet protocol in an industrial environment, for automation and production machine control. Until recently, a PLC (Programmable logic controller) would communicate with a slave machine using one of several possible open or proprietary protocols, such as Modbus, Sinec H1, Profibus, CANopen, DeviceNet or FOUNDATION Fieldbus. However, there is now increasing interest in the use of Ethernet as the link-layer protocol, with one of the above protocols as the application-layer.
Some of the advantages are:
Increased speed, up from 9.6 kbit/s with RS-232 to 1 Gbit/s with IEEE 802 over Cat5e/Cat6 cables or optical fibre
Increased overall performance
Increased distance
Ability to use standard access points, routers, switches, hubs, cables and optical fibre, which are immensely cheaper than the equivalent serial-port devices
Ability to have more than two nodes on link, which was possible with RS-485 but not with RS-232
Peer-to-peer architectures may replace master-slave ones
Better interoperability
