DCS Card ( Distributed Control System) is a computerized control system for a process or plant usually with a large number of control loops, in which autonomous controllers are distributed throughout the system, but there is central operator supervisory control.
So, This is in contrast to systems that use centralized controllers; either discrete controllers located at a central control room or within a central computer.
Moreover, The DCS concept increases reliability and reduces installation costs by localizing control functions near the process plant, with remote monitoring and supervision.
DCS’s are connected to sensors and actuators and use setpoint control to control the flow of material through the plant. A typical application is a PID controller fed by a flow meter and using a control valve as the final control element.
So, The DCS sends the setpoint required by the process to the controller which instructs a valve to operate so that the process reaches and stays at the desired set-point.
DCS’s in very high-reliability applications can have dual redundant processors with “hot” switch over on fault, to enhance the reliability of the control system.
In Short, A Distributed Control System (DCS) centralizes plant operations to provide flexibility and simplicity by allowing central control, monitoring and reporting of individual components and processes. A DCS is a design to control complex processes that can be geographically disseminated using network control elements that are distributed throughout the system.