A system which divides process control functions into specific areas interconnected by communications (normally data highways), to form a single entity. It is characterized by digital controllers and typically by central operation interfaces.
Distributed control systems consist of subsystems that are functionally integrated but may be physically separated and remotely located from one another. Distributed control systems generally have at least one shared function within the system. This may be the controller, the communication link or the display device. All three of these functions maybe shared.
A system of dividing plant or process control into several areas of responsibility, each managed by its own CPU, with the whole interconnected to form a single entity usually by communication buses of various kinds.