SCADA

Distribution Management System

Energy Management System.

These computers store values for various processes or states of interest to the industrial system. Sometimes they are regulatory records, and provide data reporting functionality designed to translate raw engineering values into CEO level reports. They are often the point of connection between the corporate network and the control network.

Human Machine Interface sometimes called the (Man Machine Interface) MMI or (Human Computer Interface) HCI.

This is a small energy management system for the home, but also refers to the appliances in the home which will communicate with it to determine the best time of day to function while saving energy or money. The smart meter may be part of this system directly or indirectly.

Heating Venting Air Conditioning

A system that performs the functions of target acquisition, tracking, data computation, and engagement control, primarily using electronic means and assisted by electromechanical devices.

Intelligent Electronic Device. Once again this performs similar functions to a PLC, but is primarily deployed in the electrical sector, for example in substations. Since these devices sometimes have to function in the presence of high voltages, they can be constructed with substantial protections for hostile environments. However, from an outsider's perspective they still gather data, provide protective logic, and execute simple controls as does a PLC or RTU.

A meter is a device capable of providing telemetry readings, and is functionally the same as your electrical meter.

Programmable Automation Controller. These provide very similar functions to PLCs, but are programmed differently, and use an open, modular, architecture. They typically differ in how they do things from PLCs, but still serve the same purpose of acquiring data and performing process control.

Programmable Logic Controller. These are similar to RTUs, but are more often deployed without their own power supply and using wired communications. They are more often found on a plant oor or factory, where controllers are close to the centre of control.

Remote Terminal Unit or sometimes Remote Telemetry Unit. This is a microprocessor used to transmit telemetry back from the field and to control devices in the field. They are often widely geographically dispersed, and use diverse wireless communications accordingly. They can run simple safety logic programs for redundancy and to reduce control delays.

Supervisory Control and Data Acquisition Server. This system typically interacts with multiple HMIs and control engineers. They are often replicated for redundancy and availability reasons.

This is the sensor data, process data, and other engineering values of interest to control engineers. It may also refer to the server used to collect such data and there is some crossover in these systems with an Historian.