ResultTransferType ObjectType Definition – OPC UA for Machinery

7.2 ResultTransferType ObjectType Definition

7.2.1 Overview

This ObjectType is a subtype of the 0:TemporaryFileTransferType defined in OPC 10000-20 and is used to transfer result data as a file.

The ResultTransferType overwrites the Method GenerateFileForRead to specify the concrete type of the generateOptions Argument of the Method. It does not specialize the GenerateFileForWrite Method of the base type as results are supposed to be only generated by the Server, not received.

The ResultTransferType is formally defined in Table 14.

Table 14 – ResultTransferType Definition

Attribute	Value
BrowseName	ResultTransferType
IsAbstract	False
Description	Transfers result data as a file.

References	Node Class	BrowseName	DataType	TypeDefinition	Other
Subtype of the 0:TemporaryFileTransferType defined in OPC 10000-20
HasComponent	Method	GenerateFileForRead			M

Conformance Units
Machinery-Result Types

7.2.2 GenerateFileForRead

The Method GenerateFileForRead is used to start the read file transaction. A successful call of this Method creates a temporary FileType Object with the file content and returns the NodeId of this Object and the file handle to access the Object. The signature of this Method is specified below. Table 15 and Table 16 specify the Arguments and AddressSpace representation, respectively.

Signature

	GenerateFileForRead (
		[in]	BaseResultTransferOptionsDataType	generateOptions,
		[out]	0:NodeId					fileNodeId,
		[out]	0:UInt32					fileHandle,
		[out]	0:NodeId					completionStateMachine)

Table 15 – GenerateFileForRead Method Arguments

Argument	Description
generateOptions	Options how to generate the file, including the resultId of the result the file belongs to.
fileNodeId	NodeId of the temporary file.
fileHandle	The FileHandle of the opened TransferFile. The FileHandle can be used to access the TransferFile methods Read and Close.
completionStateMachine	If the creation of the file is completed asynchronously, the parameter returns the NodeId of the corresponding FileTransferStateMachineType Object. If the creation of the file is already completed, the parameter is null. If a FileTransferStateMachineType object NodeId is returned, the Read Method of the file fails until the TransferState changed to ReadTransfer.

Table 16 – GenerateFileForRead Method AddressSpace Definition

Attribute	Value
BrowseName	0:GenerateFileForRead

References	Node Class	BrowseName	DataType	TypeDefinition	ModellingRule
0:HasProperty	Variable	0:InputArguments	0:Argument[]	0:PropertyType	0:Mandatory
0:HasProperty	Variable	0:OutputArguments	0:Argument[]	0:PropertyType	0:Mandatory