Field device integration in DCS engineering using a device model

Digital based actuation and measurement along with digital communication between field devices and DCS systems require an integration strategy for the engineering process of these systems. The field devices offer diagnosis, maintenance and pre-processing functions in addition to the former 4-20 mA technology. This results in an allocation of functions of the DCS system into field devices. This means that the design, commissioning, configuration, operator and visualisation tools perform an information flow based on a common data/information model. This paper describes the requirements for a device model and its use from different agents of the DCS or supervision system. The device model is specified in the object-oriented technique (with parts of UML). The device model is compared with existing device description languages (DDL) on the market like HART DDL, PROFIBUS Device Descriptions and Foundation Fieldbus DDL. The device model is used by tools which transform the electronic data sheets from the field devices to the interfaces of the DCS systems. This architectural view to the device description technology is discussed in this paper.