HistoryData parameters returned – OPC Unified Architecture

6.6 HistoryData parameters returned

6.6.1 Overview

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

Table 47 – 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 48 – 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 49 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 49 – 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 50

Table 50 – 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 51 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 51 – 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 52.

Table 52 – 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 49 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 53 – 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 54.

Table 54 – 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 47 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 55.

Table 55 – 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 56.

Table 56 – 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