DCS structure Industrial control system

functional manufacturing control levels, dcs , scada operate on levels 1 , 2.

a dcs typically uses custom-designed processors controllers, , uses either proprietary interconnections or standard protocols communication.input , output modules form peripheral components of system.

the processors receive information input modules, process information , decide control actions performed output modules. input modules receive information sensing instruments in process (or field) , output modules transmit instructions final control elements, such control valves.

the field inputs , outputs can either continuously changing analog signals e.g. 4~ 20ma dc current loop or 2 state signals switch either on or off , such relay contacts or semiconductor switch.

dcs systems can support such foundation fieldbus, profibus, hart, modbus, pc link , other digital communication bus carries not input , output signals advanced messages such error diagnostics , status signals.