Supervisory control and data acquisition systems software (SCADA) is designed for large-scale, industrial control and measurement systems that consist of a central host, one or more remote units, a communications network, and specialized software. SCADA refers to a system that collects data from various sensors at a factory, plant or in other remote locations and then sends this data to a central computer, which manages and controls the data.

Typically, supervisory control and data acquisition systems software (SCADA) is used to manage industrial processes, infrastructure processes, and facility processes. Related systems and equipment include human machine interface products (HMI), supervisory systems, remote terminal units (RTUs), and programmable logic controllers (PLCs). With SCADA systems, the central monitoring system (CMS) or master terminal unit (MTU) receives inputs from remote terminal units (RTUs) that are connected to field instrumentation such as process ovens. When polled by the SCADA master, the RTUs transmit data to the central host for processing. Supervisory control and data acquisition systems software (SCADA) then logs alarms and displays the data graphically. Today, SCADA systems are designed to run on personal computers (PCs) that use popular operating systems such as Microsoft Windows (Microsoft) and UNIX (The Open Group).

Selecting Supervisory Control and Data Acquisition Systems Software (SCADA)

Selecting supervisory control and data acquisition systems software (SCADA) requires an analysis of remote terminal units (RTU), devices which some suppliers call digital communication units (DCS). There are two main types of remote terminals: single-board and modular. Single-board RTUs are compact, ruggedized products which locate all of the input/output (I/O) modules on a single printed circuit board (PCB). Modular RTUs have a separate, central processing unit (CPU) and a backplane for connecting other I/O modules. For both types of remote terminals, specifications include power consumption, physical size, operating temperature, relative humidity, maximum addressability, and communication type.

Some supervisory control and data acquisition systems software (SCADA) works with RTUs that perform basic alarm processing, or initiates reporting to the SCADA master. Supervisory control and data acquisition systems software (SCADA) use a central monitoring system to perform a variety of tasks. These functions include real-time data collection, automatic reporting, sequential control, password protection diagnostics, and event-driven processing. SCADA software with screen blanking, help files, popup windows, and online file utilities is also available. Most supervisory control and data acquisition systems software (SCADA) support RTU communications via dial-up, Ethernet, radio frequency (RF), satellite, or serial communications.