GenerateFileForRead – OPC Unified Architecture

4.4.3 GenerateFileForRead

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.

Signature

	GenerateFileForRead(
		 [in]  BaseDataType 	generateOptions
		 [out] NodeId 		fileNodeId
		 [out] UInt32 		fileHandle
		 [out] NodeId 		completionStateMachine
		);

Argument	Description
generateOptions	The optional parameter can be used to specify server specific file generation options. To allow such options, the Server shall specify a concrete DataType in the Argument Structure for this argument in the instance of the Method. If the DataType is BaseDataType, the Client shall pass Null for this argument. Examples for concrete DataTypes are OptionSet Used to provide a bit mask for file content selection String Can be used to provide a string filter or a regular expression Structure Can be used to provide a structure with create settings e.g. to create a report Enumeration Can be used to provide a list of options
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 asynchronous, 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.

Method Result Codes (defined in Call Service)

Result Code	Description
Bad_UserAccessDenied	See OPC 10000-4 for a general description.
Bad_NotReadable	The temporary FileType Object is writeonly and can not be generated for read.

Table 14 specifies the AddressSpace representation for the GenerateFileForRead Method.

Table 14 – GenerateFileForRead Method AddressSpace definition

Attribute	Value
BrowseName	GenerateFileForRead

References	NodeClass	BrowseName	DataType	TypeDefinition	ModellingRule
HasProperty	Variable	InputArguments	Argument[]	PropertyType	Mandatory
HasProperty	Variable	OutputArguments	Argument[]	PropertyType	Mandatory

Conformance Units
Base Info TemporaryFileTransferType Base