industrial//industrial automation//SCADA//master station

The central end of a distributed SCADA: the **Master Terminal Unit** or master station coordinates acquisition from the RTUs and sends commands back to them. Supervision is built on top of it.

The central end of a distributed SCADA: the Master Terminal Unit or master station coordinates acquisition from the RTUs and sends commands back to them. Supervision is built on top of it.

The operating center is where operators drive the process from screens, alarms, histories and the setpoints they are authorized to change. It is a different function from the engineering station, where engineers change configuration and logic; both can sit in the same building and must still be kept apart.

Between an RTU and the master station the stack can be assembled from different layers: OPC UA over TCP/IP over 4G over radio, or HTTPS over TCP/IP over Ethernet over fiber. Saying "it communicates over Ethernet" says much less than it sounds (protocol layering).