UA Part 11: Historical Access - 6.6 HistoryData parameters returned

The HistoryRead Service returns different types of data depending on whether the request asked for the value Attribute of a Node or the history Events of a Node. The historyData is an Extensible Parameter whose structure depends on the functions to perform for the HistoryReadDetails parameter. See OPC 10000-4 for details on Extensible Parameters.

6.6.2 HistoryData type

Table 41 defines the structure of the HistoryData used for the data to return in a HistoryRead.

Table 41 – HistoryData structure

Name	Type	Description
HistoryData	Structure	This structured datatype is a subtype of Structure defined in OPC 10000-3
dataValues[]	DataValue	An array of values of history data for the Node. The size of the array depends on the requested data parameters.

Its representation in the AddressSpace is defined in Table 30.

Table 42 – HistoryData definition

Attribute		Value
BrowseName		HistoryData
IsAbstract		False
References	NodeClass		BrowseName	DataType	TypeDefinition	Other
Subtype of the Structure defined in OPC 10000-3
Conformance Units
Historical Access Aggregates
Historical Access Time Instance
Historical Access Read Raw

6.6.3 HistoryModifiedData type

Table 43 defines the structure of the HistoryModifiedData used for the data to return in a HistoryRead when IsReadModified = True. This DataType is a subtype of HistoryData.

Table 43 – HistoryModifiedData structure

Name	Type	Description
HistoryModifiedData	Structure	This structured datatype is a subtype of HistoryData (see 6.6.2)
modificationInfos[]	ModificationInfo
modificationTime	UtcTime	The time the modification was made. Support for this field is optional. A null shall be returned if it is not defined.
updateType	HistoryUpdateType	The modification type for the item.
userName	String	The name of the user that made the modification. Support for this field is optional. A null shall be returned if it is not defined.

Its representation in the AddressSpace is defined in Table 44

Table 44 – HistoryModifiedData definition

Attribute		Value
BrowseName		HistoryModifiedData
IsAbstract		False
References	NodeClass		BrowseName	DataType	TypeDefinition	Other
Subtype of the HistoryData defined in OPC 10000-3
Conformance Units
Historical Access Modified Values
Historical Access Annotations

6.6.4 HistoryEvent DataType

Table 45 defines the HistoryEvent parameter used for Historical Event reads.

The HistoryEvent defines a table structure that is used to return Event fields to a Historical Read. The structure is in the form of a table consisting of one or more Events, each containing an array of one or more fields. The selection and order of the fields returned for each Event are identical to the selected parameter of the EventFilter.

Table 45 – HistoryEvent structure

Name	Type	Description
HistoryEvent	Structure	This structured datatype is a subtype of Structure defined in OPC 10000-3
Events []	HistoryEventFieldList	The list of Events being delivered.
eventFields []	BaseDataType	List of selected Event fields. This will be a one-to-one match with the fields selected in the EventFilter.

Its representation in the AddressSpace is defined in Table 46.

Table 46 – HistoryEvent definition

Attribute		Value
BrowseName		HistoryEvent
IsAbstract		False
References	NodeClass		BrowseName	DataType	TypeDefinition	Other
Subtype of the Structure defined in OPC 10000-3
Conformance Units
Historical Access Events
Historical Access Modified Events

6.6.5 HistoryModifiedEvent DataType

Table 43 defines the structure of the HistoryEvent parameter used for Historical event reads when the readModified = True.

The HistoryModifyEvent defines a table structure that is used to return Event fields along with modification information to a Historical Read. The structure is in the form of a table consisting of one or more Events, each containing an array of one or more fields. The selection and order of the fields returned for each Event are identical to the selected parameter of the EventFilter. For each Event a modificationInfo record is also returned.

Table 47 – HistoryModifiedEvent structure

Name	Type	Description
HistoryModifiedEvent	Structure	This structured datatype is a subtype of HistoryEvent
modificationInfos[]	ModificationInfo	List of modifications (one record for each Event)
modificationTime	UtcTime	The time the modification was made. Support for this field is optional. A null shall be returned if it is not defined.
updateType	HistoryUpdateType	The modification type for the item.
userName	String	The name of the user that made the modification. Support for this field is optional. A null shall be returned if it is not defined.

Its representation in the AddressSpace is defined in Table 48.

Table 48 – HistoryModifiedEvent definition

Attribute		Value
BrowseName		HistoryModifiedEvent
IsAbstract		False
References	NodeClass		BrowseName	DataType	TypeDefinition	Other
Subtype of the HistoryEvent
Conformance Units
Historical Access Modified Events

6.6.6 Annotation DataType

Table 41 defines the structure of the Annotation used for the data to return in a HistoryRead.

This DataType describes Annotation structure information for the history data items. Its elements are defined in Table 49.

Table 49 – Annotation Structure

Name	Type	Description
Annotation	Structure
message	String	Annotation message or text.
userName	String	The user that added the Annotation, as supplied by the underlying system.
annotationTime	UtcTime	The time the Annotation was added. This will probably be different than the SourceTimestamp.

Its representation in the AddressSpace is defined in Table 50.

Table 50 –Annotation definition

Attribute		Value
BrowseName		Annotation
IsAbstract		False
References	NodeClass		BrowseName	DataType	TypeDefinition	Other
Subtype of the Structure defined in OPC 10000-3
Conformance Units
Historical Access Annotations