1.4 Introduction: Technological Orientation

Using the combination of a software component with a hardware component, like the driver software for a printer, the "Plug & Play" principle is also being introduced in fieldbus technology.

Moreover, as Microsoft Windows has established itself as the de-facto industry standard, there are few alternatives when choosing the operating system. The ActiveX technology introduced by Microsoft makes it possible to define interfaces which contain not only data but also functions. These possibilities have already been successfully used in conjunction with OPC (OLE for Process Control) definition.

Within FDT only interfaces in ActiveX technology are specified for the engineering components of field devices. If the engineering system implements the corresponding interfaces, the ActiveX technology provides the automatic integration of the components and takes care of the interaction between the engineering system and the software components of the devices. Furthermore the FDT interface specification allows the integration of device components with integrated user interfaces as well as the embedding of ActiveX controls provided by the device component for special engineering tasks.

The underlying object model is based on a client-server architecture that is easily extensible for future functionality. The data exchange between the devices’ software components and the engineering system is performed by means of XML (eXtensible Markup Language) which also allows for easily extending the content of the information that is exchanged in later versions of FDT. The implementation of FDT´s client server architecture is based on Microsoft COM.