2.6.1 Examples of usage

Parameter interchange between DTM and Frame Application is done via XML document. Object oriented access to data is provided when using XML parser that generates an in-memory representation of the XML data (e.g. a DOM). Instance data to be stored (persistence) can also be handled as XML document to simplify the DTM development and to have a homogeneous data handling within a DTM. But also if the data are stored as XML the content of this data is only known by DTM.

Figure 2-7-1Data access and storage

The XML document for Communication includes device data and the necessary information for routing to establish peer-to-peer connection between DTM and field device.

Figure 2-7-2 Communication

Here the DTM only knows the address information for a peer-to-peer connection. The Frame Application adds during runtime all necessary routing information.

For documentation of field devices within the project documentation and field device specific documentation XML is used in conjunction with XML style sheets (XSL) for layout. A default style sheet is supported by the Frame Application.

Figure 2-7-3 Documentation

In case of failsafe field devices the instance data that are stored in the controller (e.g. plc) after upload from the field device have to be verified by the DTM. Interchange format of this data is also an XML document.

Figure 2-7-4 Parameter verification in case of failsafe devices