Why DCS
A distributed control system (DCS) is a computerised control system for a process or plant usually with many control loops, in which autonomous controllers are distributed throughout the system, but there is no central operator supervisory control.
Sensors in a DCS control system senses the process information and then send it to the local I/O modules. The actuators connected with these modules control the process parameters. The collected information is used to the process control unit via field bus.
the DCS is a system of sensors, controllers, and associated computers that are distributed throughout a plant. Each of these elements serves a unique purpose such as data acquisition, process control, as well as data storage and graphical display.