FDT Tools
FDT-Specification Basics
ifak system GmbH
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H A P T E R
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FDT – A B
RIEF
I
NTRODUCTION
FDT-Specification Basics
The widespread technologies COM (Common Object Model),
XML (eXtensible Mark-up Language) and ActiveX (a COM
based technology for GUI elements) form the basis platform of
FDT.
COM integrates the different software components and facilitates
the interaction between them. Another example for the use of
COM as underlying concept of an automation standard can be
found in the area of online data exchange. There, the specifica-
tion OPC (DA) defines the interfaces and mechanisms for the
interaction between independent software components employ-
ing COM functionality.
Compared to OPC the aims of FDT are quite more challenging.
The COM functions transfer XML documents, which contain the
data to be communicated between different components. The
data which may be of different levels of complexity convey
information about the various aspects of the software component
(general information like manufacturer and device type; sup-
ported functions, communication data).
The ActiveX technology was chosen in order to integrate device
specific dialog elements in the HMI of the engineering system.
FDT adds new functions to the already existing ActiveX function
set, to adapt the standard to the special needs of FDT. For a
seamless integration of all components FDT specifies (with more
or less depth) the object model, interfaces and XML schemas, as
well as a session and data management.
