wilamowski-b-m-irwin-j-d-industrial-communication-systems-2011

Industrial Internet 56-9
Device_Profile
Device_Manager_Object
0..1
Application_Process_Object
Device_Identity_Object
0..1
0..*
Attributes
DeviceIdentity
ProfileIdentification
ProfileBody
DeviceManager
Device_Function_Object
1..*
ProfileRevision
ProfileName
DeviceFunction
1..∞
ApplicationProcess
ProfileSource
0..∞
ProfileClassID
nonStandardizedExtension
ProfileDate
0..∞
ProfileHeader
AdditionalInformation
ISO15745Profile
Document element
ISO15745Reference
IASInterfaceType
0..∞
ISO15745Reference_DataType
ISO15745Part
ISO15745Edition
ProfileTechnology
ProfileBody
ProfilesBody
FIGURE 56.7
Mapping of device model acc. ISO 15745 to the FDCML XML schema.
Although with ISO 15745 [ISO03] a generic approach exists, the different user organizations provided
their own schemas and mappings of the traditional description statements to XML formats (See Figure
56.7). With Field Device Configuration Markup Language (FDCML) [FDC01], a suitable description
exists not only for InterBus-S, but also for Industrial Ethernet-based devices; it is applicable by extension
for other systems, too (for example CANopen). The Electronic Data Sheet (EDS) for DeviceNet [EDS00]
is based on XML. The Generic Station Description Markup Language (GSDML) [GSD06] is supporting
PROFINET IO devices; XML-based formats for EDD are in discussion.
The benefits of XML concerning software tool support, flexibility, and extensibility have been proven
by several applications. It is relatively easy to generate documents like catalog data sheets or user interfaces
for visualization from existing device descriptions. However, XML also has some drawbacks.
Because of the mostly long XML tags, the descriptions become quite large. This may lead to storage
problems. The complexity of the XML schemas may lead to time-consuming parsing of descriptions.
The number of existing description formats will produce integration efforts again—even if the same
parsers can be used. Since this is not a technology problem, it cannot be expected that XML can solve
this—it has to be initiated by the end users.
Another typical application of XML is description of different content that will be processed and/or
displayed in applications. The flexibility of XML is a prerequisite for such type of modeling, especially
when other Internet technologies are implemented, too. For example, a Web portal for maintenance of
machines may provide different types of data—dynamic data from the machine components, static data
like description, handbooks, plans, etc. The data need to be associated together depending on the functions
the portal offers. It is not challenging to collect the data, but the assignment has to be performed
at a higher level. This assignment depends on context, for example, the user role, the communication
features, or specific phases of the life cycle.
© 2011 by Taylor and Francis Group, LLC