UA Part 5: Information Model - D.5 Node Definitions

The HasDescription ReferenceTypeis a concrete ReferenceTypeand can be used directly. It is a subtype of NonHierarchicalReferences.

The semantic of this ReferenceTypeis to reference the DataTypeDescriptionof a DataTypeEncoding.

The SourceNodeof Referencesof this type shall be an Objectof the ObjectType DataTypeEncodingType or one of its subtypes.

The TargetNodeof this ReferenceTypeshall be a Variableof the VariableType DataTypeDescriptionTypeor one of its subtypes.

Its representation in the AddressSpaceis specified in Table D.1.

Table D.1 – HasDescription ReferenceType

Attributes	Value
BrowseName	HasDescription
InverseName	DescriptionOf
Symmetric	False
IsAbstract	False
References	NodeClass	BrowseName	Comment

D.5.2 DataTypeDictionaryType

The DataTypeDictionaryType VariableTypeis used as the type for the DataTypeDictionaries. It is formally defined in Table D.2.

Table D.2 – DataTypeDictionaryType Definition

Attribute		Value
BrowseName		DataTypeDictionaryType
IsAbstract		False
ValueRank		−1 (−1 = Scalar)
DataType		ByteString
References	NodeClass		BrowseName	DataType	TypeDefinition	ModellingRule
Subtype of the BaseDataVariableType defined in 7.4.
HasProperty	Variable		DataTypeVersion	String	PropertyType	Optional
HasProperty	Variable		NamespaceUri	String	PropertyType	Optional
HasProperty	Variable		Deprecated	Boolean	Property Type	Optional

The Property DataTypeVersionis explained in D.3.

The NamespaceUriis the URI for the namespace described by the Value Attributeof the DataTypeDictionary. This is not always the same as the NamespaceUriof the DataType NodeId.

The Deprecated Propertyis used to indicate that all of the DataTypedefinitions represented by the DataTypeDictionaryTypeare available through a DataTypeDefinition Attribute. Servers that provide DataTypedefinitions as a DataTypeDefinition Attributeand through a DataTypeDictionaryTypeshall expose this Property.

D.5.3 DataTypeDescriptionType

The DataTypeDescriptionType VariableTypeis used as the type for the DataTypeDescriptions. It is formally defined in Table D.3.

Table D.3 – DataTypeDescriptionType Definition

Attribute		Value
BrowseName		DataTypeDescriptionType
IsAbstract		False
ValueRank		-1 (-1 = Scalar)
DataType		String
References	NodeClass		BrowseName	DataType	TypeDefinition	ModellingRule
Subtype of the BaseDataVariableType defined in 7.4.
HasProperty	Variable		DataTypeVersion	String	PropertyType	Optional
HasProperty	Variable		DictionaryFragment	ByteString	PropertyType	Optional

The PropertiesDataTypeVersion and DictionaryFragment are explained in D.3.

D.5.4 DataTypeSystemType

The DataTypeSystems ObjectTypeis used as type for the DataTypeSystems. There are no Referencesspecified for this ObjectType. It is formally defined in Table D.4.

Table D.4 – DataTypeSystemType Definition

Attribute			Value
BrowseName			DataTypeSystemType
IsAbstract			False
References	NodeClass	BrowseName		DataType	TypeDefinition	ModellingRule
Subtype of the BaseObjectType defined in 6.2.

D.5.5 OPC Binary

OPC Binary is a standard DataTypeSystemdefined by OPC. It is represented in the AddressSpaceby an Object Node. The OPC Binary DataTypeSystemis defined in OPC 10000-3. OPC Binary uses XML to describe complex binary data values. The “OPC Binary” Objectis formally defined in Table D.5.

Table D.5 – OPC Binary Definition

Attribute	Value
BrowseName	OPC Binary
References		NodeClass	BrowseName	Comment
HasTypeDefinition		ObjectType	DataTypeSystemType	Defined in D.5.4

D.5.6 XML Schema

XML Schema is a standard DataTypeSystemdefined by the W3C. It is represented in the AddressSpaceby an Object Node. XML Schema documents are XML documents whose xmlns attribute in the first line is:

schema xmlns =http://www.w3.org/1999/XMLSchema

The “XML Schema” Objectis formally defined in Table D.6.

Table D.6 – XML Schema Definition

Attribute		Value
BrowseName		XML Schema
References	NodeClass		BrowseName	Comment
HasTypeDefinition	ObjectType		DataTypeSystemType	Defined in D.5.4