Necessary extensions of fieldbus systems for distributed processing

Supervisory and control systems are characterized by proprietary hardware, software and communication systems. As a result of the introduction of standardized fieldbus systems into practical use, it becomes possible and necessary to provide the interoperability of application functions and to get open distributed supervisory and control systems (DSCSs). Furthermore it is necessary to add to the control loop between the technological process and the supervisory and control functions a second control loop between the supervisory and control functions and the management of the DSCS. This paper shows which application functions are necessary for distributed processing, classifies and models control functions and management functions and derives an information model for the device. Furthermore, it is shown which parts of the developed model are already specified in PROFIBUS-PA and which other standardisation activities are under way