Scada

SCADA stands for Supervisory Control and Data Acquisition. It is a type of industrial control system used for remote monitoring and control of large-scale processes across multiple sites. A SCADA system collects data from field devices, communicates it to a central supervisory computer, and issues commands to equipment such as valves, pumps, and switches.

A typical SCADA system comprises field devices (RTUs and PLCs), a communications network, a supervisory computer or server, and human-machine interfaces used by operators. Data from field devices is acquired, time-stamped, and stored in a historian for trend analysis and reporting. Operators use HMIs to visualize processes, monitor alarms, and issue control actions.

Architecture is often multi-tiered, with a field layer, a network/communication layer, and a SCADA server/historian layer. Systems may be centralized, distributed, or redundant to improve reliability and security. SCADA typically integrates with other IT systems for data analytics and reporting.

Applications span utility infrastructure (electric power, water and wastewater, gas, and district heating), manufacturing, oil and gas, transportation, and building automation.

Standards and interoperability: various industrial protocols such as IEC 60870-5, IEC 61850, DNP3, Modbus, and OPC UA enable communication between field devices and SCADA servers. Security considerations emphasize defense in depth, network segmentation, strong access controls, encryption where feasible, and regular patching.

History: early SCADA emerged in the 1960s and 1970s to automate supervisory control of remote processes. Over time, SCADA has evolved with improved communication, real-time data processing, historians, and greater integration with IT and cloud-based analytics.

Note on scope: SCADA is distinct from PLCs/RTUs; these field devices perform local control actions, while SCADA provides supervisory oversight and data aggregation for multiple sites.