DCSs may control any of a number of different equipment types, including: Because DCS systems require near-constant operator interaction at the HMI, redundancy is crucial.ĭistributed control systems are most frequently used in batch-oriented or continuous process operations, such as oil refining, power generation, petrochemical manufacturing, papermaking, food and beverage manufacturing, pharmaceutical production, and cement processing.

Redundancy increases equipment reliability, leaving the DCS operator to concentrate on displays, software, and applications.

If the control system fails and the flares cease burning, gas collects and pools, causing an extremely dangerous situation. In such an environment, a control system governs flares that constantly burn gas. A petroleum refinery is a good example of safety-critical plant.

Many DCSs control safety-critical processes in which failure or outage of equipment could cause personal injury or loss of life.

Redundant elements are necessary in DCSs because for two main reasons: Redundant engineering increases a system's reliability by using backup processors in case of primary processor failure. Most distributed control systems are designed with redundant elements. While a DCS ultimately governs the functionality of its networked components, the same components can often be reprogrammed for use in other applications. It is important to note that many DCS components can also operate as standalone devices. DCSs are usually networked using standard protocols such as PROFIBUS and Ethernet, the latter of which is used in this particular system. The master controllers connect to individual computers and servers, which are further connected to video output devices and a human machine interface (HMI), which is the actual point of user control. Individual controllers, supervised by master controllers, make up the lowest 'field' or 'plant' level of the hierarchy. ComponentsĭCSs are by definition hierarchical systems, although not all systems share an identical hierarchy.

DCSs aim to centralize plant operations to allow control, monitoring, and reporting of individual components and processes at a single location. The controllers are networked to a central console. Characteristics and DesignĪ distributed control system involves the placement of multiple controllers within a plant or manufacturing process. They offer flexibility, extended equipment life, simplicity of new equipment integration, and centralized maintenance when used in an industrial environment. Distributed control systems (DCS) use decentralized elements or subsystems to control distributed processes or manufacturing systems.

Scada and distributed control system