DCS

Distributed control systems (DCSs) are systems used to control manufacturing processes that are continuous or batch-oriented, such as oil refining, petrochemicals, central station power generation, fertilizers, pharmaceuticals, food and beverage manufacturing, cement production, steel making, and paper making. DCSs are connected to sensors and actuators and use set point control to control the flow of material through the plant. The most common example is a set point control loop consisting of a pressure sensor, controller, and control valve. Pressure or flow measurements are transmitted to the controller, usually through the aid of a signal conditioning input/output (I/O) device. When the measured variable reaches a certain point, the controller instructs a valve or actuation device to open or close until the fluid flow process reaches the desired set point. Large oil refineries have many thousands of I/O points and employ very large DCSs. Processes are not limited to fluid flow through pipes, however, and can also include things like paper machines and their associated quality controls

      The following are the list of vendors of most famous DCSs

• ABB Ltd.
• Emerson Electric Co.
• Honeywell International Inc.
• Siemens AG
• Bharat Heavy Electrical Ltd.
• General Electric Co.
• Invensys plc
• Mitsubishi Heavy Industries Ltd.
• Metso Corp.
• Omron Corp.
• Rockwell Automation Inc.
• Toshiba International Corp.
• Control Systems International Inc.
• Yokogawa Electric Corp.