SCADA HMI

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SCADA HMI is a core component of a SCADA Monitoring System

SCADA is an acronym for Supervisory Control and Data Acquisition. The term can be used in two different contexts, depending on the users geographic location. In North America, SCADA refers specifically to large distributed measurement and control systems. For the rest of the world, SCADA is not indicative of size, as systems of any size can be classified in this way.

A SCADA HMI is the Human-Machine Interface that a SCADA system utilizes to communicate with a human network operator. Alternately referred to as a "master station", this computer combines input from RTUs (Remote Telemetry Units) that communicate with individual sensors along a network.

HMI Combines Network Alarms into a Single Window View
The HMI has many different functions within the SCADA system. The SCADA HMI continuously monitors all of the sensors on a network. When an alarm occurs, the HMI retrieves that alarm from the RTU and translates it into a form that is usable by the human network operator. By looking at the HMI, this operator is notified of individual alarms throughout the network in one comprehensive window.

This comprehensive window allows operators to see a comprehensive view of the entire SCADA system. The SCADA HMI can also provide more detail about any single alarm when the operator makes a request through the human-machine interface.

One of the most important functions of a SCADA HMI is also to provide for processing of all the data gathered from the sensors. The HMI can generate report logs for the network operator, summarizing historical trends to indicate possible future problems along the network.

Advanced SCADA HMI Programs Display Graphical Representations of Alarm Status
An HMI installed within the SCADA system frequently will include a drawing program that can be used by network operators. The graphic representations provided by these drawing programs can be very simple or extremely complex, depending upon the makeup of the network, and the level of detail desired. For example, a SCADA HMI drawing program could provide an illustration of a single traffic light that in monitored on the network. The light would be depicted onscreen as it appears to drivers on the road, switching between green, yellow, and red accordingly.

The HMI is a critical component of a network monitoring system. Without an HMI installed within the SCADA network, operators would be unable to see or act upon the data gathered by RTUs and individual sensors. An HMI program not only allows operators to understand this data, but can also provide operators extensive reports related to network alarms.