A specific type FdtParameter is defined, which is an extension of DataItemType (see Table 27).

Table 27 – FdtParameter Definition

Attribute

Value

BrowseName

FdtParameter

IsAbstract

False

ValueRank

−2 (−2 = Any)

DataType

0:BaseDataType

References

NodeClass

BrowseName

DataType

TypeDefinition

Other

Subtype of DataItemType/ HasTypeDefinition FdtParameter

0:HasProperty

Variable

DisplayFormat

0:String

0:PropertyType

O

0:HasProperty

Variable

AlarmType

AlarmType

0:PropertyType

O

0:HasProperty

Variable

RangeType

RangeType

0:PropertyType

O

0:HasProperty

Variable

SubstitutionType

SubstitutionType

0:PropertyType

O

0:HasProperty

Variable

ApplicationId

ApplicationIdEnumeration

0:PropertyType

O

0:HasProperty

Variable

0:EURange

0:Range

0:PropertyType

O

0:HasProperty

Variable

0:EngineeringUnits

0:EUInformation

0:PropertyType

O

0:HasProperty

Variable

0:EnumStrings

0:LocalizedText[]

0:PropertyType

O

0:HasProperty

Variable

SemanticInfo

SemanticInfoType

0:PropertyType

O

0:HasProperty

Variable

DataRef

DataRefType

0:PropertyType

O

0:HasProperty

Variable

AlarmDataRef

DataRefType

0:PropertyType

O

0:HasProperty

Variable

RangeDataRef

DataRefType

0:PropertyType

O

0:HasProperty

Variable

SubstituteDataRef

DataRefType

0:PropertyType

O

NonHierarchicalReferences

HasIOSignalRef

ObjectType

FdtIoSignalInfoType

The FdtParameter is a concrete type and can be used directly.

DisplayFormat is a format string for numerical data, compliant to .NET string format definitions.

If the DataType of the FdtParameter is an Enumeration DataType, then EnumStrings are used according to OPC 10000-3.

EURange and EngineeringUnits are used as defined in OPC 10000-8 for the AnalogueItem variable type.

SemanticInfo provides additional semantic information for the parameter (e.g., a reference to a definition in a device profile).

If the FdtParameter represents a structured data information, then ApplicationId may be used to categorize the use case for the data structure.

The DataRefType properties are used to reference related FdtParameters:

  • DataRef, provides references to other data. Information about the type of reference is provided by the SemanticInfo of the DataRefType.
  • AlarmDataRef, provides references to alarm information,
  • RangeDataRef, provides references to range information, and
  • SubstituteDataRef, provides references to substitute value settings.

If the FdtParameter represents alarm information, then AlarmType categorizes the available alarm type.

If the FdtParameter represents range information, then RangeType distinguishes whether the data represents an upper range or a lower range.

If the FdtParameter represents substitute information, then SubstitutionType specifies which value shall be used when a substitute value is needed.

The HasIOSignalRef reference, provides a reference to the description of an IO signal that corresponds to the FdtParameter.