Distributed Control System

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A whole family of terms denote the accessing of measuring devices, automated analysis, human understandable display and interactive control, and the control of actuators, such as: Industrial Automation and Control Systems, Industrial Control Systems, Process Control Systems, Supervisory Control and Data Acquisition, and Distributed Control Systems.

Definitions

National Definitions

United States

NIST
In a control system, refers to control achieved by intelligence that is distributed about the process to be controlled, rather than by a centrally located single unit. (from: NIST SP 800-82 Rev. 2) [1]


Standard Definition

ISA-62443-1-1

Distributed Control System is a type of control system in which the system elements are dispersed but operated in a coupled manner. [2]

Distributed Control System refers to control achieved by intelligence that is distributed about the process to be controlled, rather than by a centrally located single unit. [3]]
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NIST

DCS are used to control industrial processes such as electric power generation, oil refineries, water and wastewater treatment, and chemical, food, and automotive production. DCS are integrated as a control architecture containing a supervisory level of control overseeing multiple, integrated sub-systems that are responsible for controlling the details of a localized process. Product and process control are usually achieved by deploying feed back or feed forward control loops whereby key product and/or process conditions are automatically maintained around a desired set point. To accomplish the desired product and/or process tolerance around a specified set point, specific PLCs are employed in the field and proportional, integral, and/or derivative settings on the PLC are tuned to provide the desired tolerance as well as the rate of self-correction during process upsets. DCS are used extensively in process-based industries. [1].

These systems are usually process control or discrete part control systems. A DCS uses a centralized supervisory control loop to mediate a group of localized controllers that share the overall tasks of carrying out an entire production process. By modularizing the production system, a DCS reduces the impact of a single fault on the overall system. In many modern systems, the DCS is interfaced with the corporate network to give business operations a view of production. [1].

See also

Notes

  1. 1.0 1.1 1.2 NIST Glossary
  2. ISA99 Committee Master Glossary - ISA-6443-1-1
  3. The Automation, Systems, and Instrumentation Dictionary, 4th Edition, ISA, 2003