The acronym SCADA stands for Supervisory Control And Data Acquisition. In reality, the primary purpose of SCADA is to monitor, control and alarm plant or regional operating systems from a central location. While override control is possible, it is infrequently utilized; however control set points are quite regularly changed by SCADA.
In a municipal context, "plant" systems are typically water and wastewater treatment facilities, while "regional" systems include intake and/or effluent structures, pumping stations, chlorination stations, control valve stations and the like.
What makes up a SCADA system?
There are three main elements to a SCADA system, various RTU's (Remote TelemetryUnits), communications and an HMI (Human Machine Interface).
Each RTU effectively collects information at a site, while communications bring that information from the various plant or regional RTU sites to a central location, and occasionally returns instructions to the RTU.
The HMI displays this information in an easily understood graphics form, archives the data received, transmits alarms and permits operator control as required.
Communication within a plant will be by data cable, wire or fiber-optic, while regional systems most commonly utilize radio. The HMI is essentially a PC system running powerful graphic and alarm software programs.
Why is SCADA so popular? The major attraction of SCADA to a municipality is the ability to significantly reduce operating labor costs, while at the same time actually improve plant or regional system performance and reliability. Information gathering within a plant no longer requires personnel to spend time wandering all over the site, and correspondingly the frequency of field site inspections required in a regional system can be minimized.
Costly after-hours alarm call-outs can often be avoided since a SCADA system will indicate the nature and degree of a problem, while the ability to remotely