SCADA Human Machine Interface (HMI)

Supervisory Control and Data Acquisition (SCADA) systems require a Human Machine Interface (HMI). This interface presents data collected from Remote Telemetry Units (RTUs) and Intelligent Electronic Devices (IEDs). It also allows an operator to control the RTUs / IEDs or connected equipment. The SCADA HMI is a core component of a Remote Monitoring and Controlling System.

SCADA systems can be quite large and spread over vast geographical areas. They can also be small, sometimes limited to a single manufacturing facility.


A SCADA HMI, also referred to as a SCADA Master, can provide a number of helpful extensions for network alarm management. RTU data can be filtered, analyzed and monitored against operational standards. Out-of-range data can generate alerts to operators or maintenance personnel as required.

HMI Presents Alarm Data for Management
When an alarm occurs, an HMI like the DPS Telecom T/Mon master alarm system, presents the data in a form that is usable by the human network operator. By looking at the HMI, the operator can quickly make informed decisions about any required response from a few comprehensive windows.

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 on screen 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.