Distributed Control System (DCS)

A distributed control system (DCS) is a digital automated industrial control system (ICS) that uses geographically distributed control loops throughout a factory, machine or control area. The goal of a DCS is to control industrial processes to increase their safety, cost-effectiveness and reliability.
A control system is a set of mechanical or electronic devices that regulate other devices or systems through the use of control loops. Control loops are systems composed of all the hardware and software control functions needed for measurements and adjustments in an individual process. Control systems are a central part of industrial and process automation systems.

DCSes are made up of control elements distributed throughout a plant or factory. These control elements include computers, sensors and controllers. Each element serves a specific purpose, such as data collection, data storage or process control. Unlike a centralized control system that operates all machines, a DCS enables each part of a machine to have its own dedicated controller that runs the operation.
A DCS has several local controllers throughout the factory. A high-speed communication network connects the local controllers. While each controller works autonomously, there is central supervisory control run by an operator.

Having the control system architecture distributed around the factory or plant provides an effective control, efficiency and process quality strategy. Additionally, if a piece of the DCS architecture fails, a plant can continue to operate. For these reasons, DSCes are commonly found in industrial fields and processing or manufacturing plants.
A DCS is functionally similar to supervisory control and data acquisition (SCADA) industrial control applications. SCADA systems are used in power plants, oil and gas refining, telecommunications, transportation, and water and waste control. They tend to be used in situations where the control center has a more remote location.

Where is a DCS commonly used?
A DCS is commonly used in industrial process industries, including the following:

• agriculture
• chemical plants
• petrochemical and refineries
• nuclear power plants
• water and sewage treatment plants
• food processing
• automobile manufacturing
• pharmaceutical manufacturing