Glossary Updates12 new terms added to the glossaries · October 2, 2026, 22:44 CEST
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Glossary · HMI, SCADA and operations

Distributed control system (DCS)

Also known as: DCS, Process control system (PCS)

German: Prozessleitsystem (PLS)

In process automation, a distributed control system (DCS) is an integrated control system in which controllers distributed across the plant execute control functions, while operator stations, engineering tools, historian and alarm system share one common database and configuration environment.

  • HMI and SCADA
  • Process industry

In one sentence

A DCS is an integrated plant control system with distributed controllers and a common database for operation, engineering and alarms.

Example

A refinery runs its units on a DCS with redundant controllers per process area, a central control room and one engineering environment for all loops and displays.

How it applies

  • Engineering: A DCS is configured rather than programmed in many areas: function block libraries for loops, standard faceplates, integrated alarm and historian functions. Changes are made in one engineering environment and downloaded to controllers, often online.
  • Operation: DCS installations run continuously for years, so Redundancy of controllers, networks and servers and online change capability are central.
  • Documentation: Document the control strategy per unit, the library versions and the system architecture. Because DCS databases are large, generated documentation (loop reports, alarm lists) and controlled documents need a clear source of truth.

DCS vs. SCADA and PLC

A DCS integrates control and supervision in one system and is typical for process plants with many loops. Supervisory control and data acquisition (SCADA) supervises distributed, often geographically spread equipment controlled by PLCs or RTUs. The boundaries have blurred, as PLC-based systems now offer DCS-like features.

By knowledge.aitechdoc.world · Published September 26, 2026 · Last reviewed

Source: AI TechDoc Knowledge editorial definition, based on process control system practice

Definitions follow the cited standards and specifications. Where a source is a copyrighted publication, such as an ISO, IEC or EN standard, the definition is a close paraphrase, not a verbatim quotation, so as not to infringe copyright. We recommend reading the original publication. The sections “How it applies” are editorial commentary by AI TechDoc Knowledge and are not part of any standard.

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