industrial//industrial automation//DCS

A **Distributed Control System** controls large industrial processes with many controllers spread over the plant instead of a single one. Typical traits: high availability, redundancy, integrated engineering, alarm management, PID control, a historian, operator stations, and a very large number of signals.

A Distributed Control System controls large industrial processes with many controllers spread over the plant instead of a single one. Typical traits: high availability, redundancy, integrated engineering, alarm management, PID control, a historian, operator stations, and a very large number of signals.

The tempting summary, "a hundred redundant PLCs connected, plus alarms", is a good first intuition and a misleading definition. A DCS is not bought as a hundred PLCs wired together. Its controllers, networks, engineering stations, operator stations, alarms, history, redundancy and configuration management are designed from the start to work as one control system with the rest of the plant. The integration is the product.

Classic platforms: Emerson DeltaV, Honeywell Experion, Yokogawa CENTUM, ABB System 800xA, Siemens PCS 7 and PCS neo. DeltaV is not "a big PLC": from one engineering environment you configure controllers, PID loops, alarms, graphics, historization, redundancy, communications and stations.

Its natural terrain is process automation: keep pressure at 5 bar, level at 65 %, temperature at 180 degrees and flow at 200 t/h while the variables interact, which means tens, hundreds or thousands of control loops managed together.

Operation and engineering are separated on purpose: the engineering station changes logic and configuration, the operating center drives the process (HMI).