Abstract: A plant control system includes a plant control network for performing the overall supervision of a process being controlled. The plant control network has at least one external bus for operatively connecting a corresponding interface apparatus to the plant control network. Further, each interface apparatus interfaces with at least one predetermined field device, each field device being a type having a corresponding predetermined signal type. The interface apparatus comprises a controller for controlling the input/output (I/O) of the interface apparatus. At least one I/O module, connected to the controller, preprocesses information signals to and from the predetermined field device connected to the I/O module. The preprocessing is a translation between the signal type of the field device and signals compatible with the controller.