Industrial control system

An industrial control system, or ICS, is the electronic control equipment and instrumentation used to run an industrial process. It ranges from a few panel-mounted controllers to large distributed control systems with thousands of field connections. Sensors report process variables, the system compares them with setpoints and sends commands to final control elements such as control valves. Larger installations are usually built from supervisory control and data acquisition systems, distributed control systems and programmable logic controllers, in industries such as chemical processing, pulp and paper, power generation, oil and gas, and telecommunications. Control moved from panels beside the plant to a central control room, then to networked computer-based control. Programmable logic controllers grew out of automotive production lines to replace relay racks, while SCADA grew from power, gas and water distribution. The 1993 IEC 61131-3 standard encouraged reusable, hardware-independent control software.