This document describes an information model for file transfer. Files could be modelled in OPC UA as simple Variables using ByteStrings. However, the overall message size in OPC UA is limited due to resources and security issues (denial of service attacks). Only accessing parts of the array can lead to concurrency issues if one client is reading the array while others are manipulating it. Therefore, the ObjectType FileType is defined representing a file with Methods to access the file. The life-cycle of a file stored on a hard disk and an instance of the FileType representing the file in an OPC UA AddressSpace can be independent.

In addition to representing individual files this document also defines a way to represent a whole file system or a part of a file system. This can be done using the FileDirectoryType in combination with the FileType. The FileDirectoryType provides Methods to create, delete, and move files and directories. The root of a file system or part of a file system is represented by an instance of the FileDirectoryType with the BrowseName FileSystem. All directories below the root directory are represented by instances of the FileDirectoryType or a subtype. All files below the root directory are represented by instances of the FileType or a subtype.

In different situations like transfer of configuration files or firmware update, the files are temporary, and an additional handshake is necessary to create the file for reading or to apply the file after writing it to the server. This use case is covered by the TemporaryFileTransferType defined in this document.

This ObjectType defines a type for files. It is formally defined in Table 1.

Table 1 – FileType

Attribute	Value
BrowseName	FileType
IsAbstract	False
References		NodeClass	BrowseName	DataType	TypeDefinition	ModellingRule
Subtype of the BaseObjectType defined in OPC 10000-5
HasProperty		Variable	Size	UInt64	PropertyType	Mandatory
HasProperty		Variable	Writable	Boolean	PropertyType	Mandatory
HasProperty		Variable	UserWritable	Boolean	PropertyType	Mandatory
HasProperty		Variable	OpenCount	UInt16	PropertyType	Mandatory
HasProperty		Variable	MimeType	String	PropertyType	Optional
HasComponent		Method	Open	Defined in 4.2.2		Mandatory
HasComponent		Method	Close	Defined in 4.2.3		Mandatory
HasComponent		Method	Read	Defined in 4.2.4		Mandatory
HasComponent		Method	Write	Defined in 4.2.5		Mandatory
HasComponent		Method	GetPosition	Defined in 4.2.6		Mandatory
HasComponent		Method	SetPosition	Defined in 4.2.7		Mandatory
HasProperty		Variable	MaxByteStringLength	UInt32	PropertyType	Optional
HasProperty		Variable	LastModifiedTime	DateTime	PropertyType	Optional
Conformance Units
Base Info FileType Base

Size defines the size of the file in Bytes. When a file is opened for write, the size might not be accurate. If the Server can not accurately determine the size of the file, the Size Property shall be returned to a Client with a StatusCode of Bad_NotSupported.

Writable indicates whether the file is writable. It does not take any user access rights into account, i.e., although the file is writable this may be restricted to a certain user / user group. The Property does not consider whether the file is currently opened for writing by another client and thus currently locked and not writable by others.

UserWritable indicates whether the file is writable taking user access rights into account. The Property does not consider whether the file is currently opened for writing by another client and thus currently locked and not writable by others.

OpenCount indicates the number of currently valid file handles on the file.

The optional Property MimeType contains the media type of the file based on RFC 2046.

Note that all Methods on a file require a fileHandle, which is returned in the Open Method.

The optional MaxByteStringLength Property indicates the maximum number of bytes of the read and write buffers. If this Property is not present then the maximum size is defined by the MaxByteStringLength Property of the ServerCapabilitiesType defined in OPC 10000-5.

The optional LastModifiedTime Property indicates the time the file was last modified. The Property shall be updated whenever the Server detects that the file has changed.

Open is used to open a file represented by an Object of FileType. When a client opens a file it gets a file handle that is valid while the session is open. Clients shall use the Close Method to release the handle when they do not need access to the file anymore. Clients can open the same file several times for read. A request to open for writing shall return Bad_NotWritable when the file is already opened. A request to open for reading shall return Bad_NotReadable when the file is already opened for writing.

Signature

Open(

[in] Byte mode

[out] UInt32 fileHandle

);

Argument	Description
mode	Indicates whether the file should be opened only for read operations or for read and write operations and where the initial position is set. The mode is an 8-bit unsigned integer used as bit mask with the structure defined in the following table: Field Bit Description Read 0 The file is opened for reading. If this bit is not set the Read Method cannot be executed. Write 1 The file is opened for writing. If this bit is not set the Write Method cannot be executed. EraseExisting 2 This bit can only be set if the file is opened for writing (Write bit is set). The existing content of the file is erased and an empty file is provided. Append 3 When the Append bit is set the file is opened at end of the file, otherwise at begin of the file. The SetPosition Method can be used to change the position. Reserved 4:7 Reserved for future use. Shall always be zero.
fileHandle	A handle for the file used in other method calls indicating not the file (this is done by the Object of the Method call) but the access request and thus the position in the file. The fileHandle is generated by the server and is unique for the Session. Clients cannot transfer the fileHandle to another Session but need to get a new fileHandle by calling the Open Method.

Method Result Codes (defined in Call Service)

Result Code	Description
Bad_NotReadable	See OPC 10000-4 for a general description. File might be locked and thus not readable.
Bad_NotWritable	See OPC 10000-4 for a general description.
Bad_InvalidState	See OPC 10000-4 for a general description. The file is locked and thus not writable.
Bad_InvalidArgument	See OPC 10000-4 for a general description. Mode setting is invalid.
Bad_NotFound	See OPC 10000-4 for a general description.
Bad_UnexpectedError	See OPC 10000-4 for a general description.

Table 2 specifies the AddressSpace representation for the Open Method.

Table 2 – Open Method AddressSpace definition

Attribute	Value
BrowseName	Open
References	NodeClass	BrowseName	DataType	TypeDefinition	ModellingRule
HasProperty	Variable	InputArguments	Argument[]	PropertyType	Mandatory
HasProperty	Variable	OutputArguments	Argument[]	PropertyType	Mandatory
Conformance Units
Base Info FileType Base

Close is used to close a file represented by a FileType. When a client closes a file, the handle becomes invalid.

Signature

Close(

[in] UInt32 fileHandle

);

Argument	Description
fileHandle	A handle indicating the access request and thus indirectly the position inside the file.

Method Result Codes (defined in Call Service)

Result Code	Description
Bad_InvalidArgument	See OPC 10000-4 for a general description. Invalid file handle in call.

Table 3 specifies the AddressSpace representation for the Close Method.

Table 3 – Close Method AddressSpace definition

Attribute	Value
BrowseName	Close
References	NodeClass	BrowseName	DataType	TypeDefinition	ModellingRule
HasProperty	Variable	InputArguments	Argument[]	PropertyType	Mandatory
Conformance Units
Base Info FileType Base

Read is used to read a part of the file starting from the current file position. The file position is advanced by the number of bytes read.

Signature

Read(

[in] UInt32 fileHandle

[in] Int32 length

[out] ByteString data

);

Argument	Description
fileHandle	A handle indicating the access request and thus indirectly the position inside the file.
Length	Defines the length in bytes that should be returned in data, starting from the current position of the file handle. If the end of file is reached all data until the end of the file is returned. The Server is allowed to return less data than specified length. Only positive values are allowed.
Data	Contains the returned data of the file. If the ByteString is empty it indicates that the end of the file is reached.

Method Result Codes (defined in Call Service)

Result Code	Description
Bad_InvalidArgument	See OPC 10000-4 Invalid file handle in call or non-positive length.
Bad_UnexpectedError	See OPC 10000-4 for a general description.
Bad_InvalidState	See OPC 10000-4 for a general description. File was not opened for read access.

Table 4 specifies the AddressSpace representation for the Read Method.

Table 4 – Read Method AddressSpace definition

Attribute	Value
BrowseName	Read
References	NodeClass	BrowseName	DataType	TypeDefinition	ModellingRule
HasProperty	Variable	InputArguments	Argument[]	PropertyType	Mandatory
HasProperty	Variable	OutputArguments	Argument[]	PropertyType	Mandatory
Conformance Units
Base Info FileType Base

Write is used to write a part of the file starting from the current file position. The file position is advanced by the number of bytes written.

Signature

Write(

[in] UInt32 fileHandle

[in] ByteString data

);

Argument	Description
fileHandle	A handle indicating the access request and thus indirectly the position inside the file.
data	Contains the data to be written at the position of the file. It is server-dependent whether the written data are persistently stored if the session is ended without calling the Close Method with the fileHandle. Writing an empty or null ByteString returns a Good result code without any affect on the file.

Method Result Codes (defined in Call Service)

Result Code	Description
Bad_InvalidArgument	See OPC 10000-4 for a general description. Invalid file handle in call.
Bad_NotWritable	See OPC 10000-4 for a general description. File might be locked and thus not writable.
Bad_InvalidState	See OPC 10000-4 for a general description. File was not opened for write access.

Table 5 specifies the AddressSpace representation for the Write Method.

Table 5 – Write Method AddressSpace definition

Attribute	Value
BrowseName	Write
References	NodeClass	BrowseName	DataType	TypeDefinition	ModellingRule
HasProperty	Variable	InputArguments	Argument[]	PropertyType	Mandatory
Conformance Units
Base Info FileType Base

GetPosition is used to provide the current position of the file handle.

Signature

GetPosition(

[in] UInt32 fileHandle

[out] UInt64 position

);

Argument	Description
fileHandle	A handle indicating the access request and thus indirectly the position inside the file.
Position	The position of the fileHandle in the file. If a Read or Write is called it starts at that position.

Method Result Codes (defined in Call Service)

Result Code	Description
Bad_InvalidArgument	See OPC 10000-4 for a general description. Invalid file handle in call.

Table 6 specifies the AddressSpace representation for the GetPosition Method.

Table 6 – GetPosition Method AddressSpace definition

Attribute	Value
BrowseName	GetPosition
References	NodeClass	BrowseName	DataType	TypeDefinition	ModellingRule
HasProperty	Variable	InputArguments	Argument[]	PropertyType	Mandatory
HasProperty	Variable	OutputArguments	Argument[]	PropertyType	Mandatory
Conformance Units
Base Info FileType Base

SetPosition is used to set the current position of the file handle.

Signature

SetPosition(

[in] UInt32 fileHandle

[in] UInt64 position

);

Argument	Description
fileHandle	A handle indicating the access request and thus indirectly the position inside the file.
Position	The position to be set for the fileHandle in the file. If a Read or Write is called it starts at that position. If the position is higher than the file size the position is set to the end of the file.

Method Result Codes (defined in Call Service)

Result Code	Description
Bad_InvalidArgument	See OPC 10000-4 for a general description. Invalid file handle in call.

Table 7 specifies the AddressSpace representation for the SetPosition Method.

Table 7 – SetPosition Method AddressSpace definition

Attribute	Value
BrowseName	SetPosition
References	NodeClass	BrowseName	DataType	TypeDefinition	ModellingRule
HasProperty	Variable	InputArguments	Argument[]	PropertyType	Mandatory
Conformance Units
Base Info FileType Base

This ObjectType defines a type for the representation of file directories. It is formally defined in Table 8.

It is expected that OPC UA Servers will create vendor-specific subtypes of the FileDirectoryType with additional functionalities like Methods for creating symbolic links or setting access permissions. OPC UA Clients providing specialized file transfer user interfaces should be prepared to expose such additional Methods to the user.

Table 8 – FileDirectoryType

Attribute	Value
BrowseName	FileDirectoryType
IsAbstract	False
References		NodeClass	BrowseName	DataType	TypeDefinition	Modelling Rule
Subtype of the FolderType defined in OPC 10000-5
Organizes		Object	<FileDirectoryName>		FileDirectoryType	OptionalPlaceholder
Organizes		Object	<FileName>		FileType	OptionalPlaceholder
HasComponent		Method	CreateDirectory	Defined in 4.3.3		Mandatory
HasComponent		Method	CreateFile	Defined in 4.3.4		Mandatory
HasComponent		Method	Delete	Defined in 4.3.5		Mandatory
HasComponent		Method	MoveOrCopy	Defined in 4.3.6		Mandatory
Conformance Units
Base Info FileDirectoryType Base

Instances of the ObjectType contain a list of FileDirectoryType Objects representing the subdirectories of the file directory represented by the instance of this ObjectType.

Instances of the ObjectType contain a list of FileType Objects representing the files in the file directory represented by the instance of this ObjectType.

The support of file directory structures is declared by aggregating an instance of the FileDirectoryType with the BrowseName FileSystem as illustrated in Figure 1.

Figure 1 – FileSystem example

The Object representing the root of a file directory structure shall have the BrowseName FileSystem. An OPC UA Server may have different FileSystem Objects in the AddressSpace. HasComponent is used to reference a FileSystem from aggregating Objects like the Objects Folder or the Object representing a device.

CreateDirectory is used to create a new FileDirectoryType Object organized by this Object.

Signature

CreateDirectory(

[in] String directoryName

[out] NodeId directoryNodeId

);

Argument	Description
directoryName	The name of the directory to create. The name is used for the BrowseName and DisplayName of the directory object and also for the directory in the file system. For the BrowseName, the directoryName is used for the name part of the QualifiedName. The namespace index is Server specific. For the DisplayName, the directoryName is used for the text part of the LocalizedText. The locale part is Server specific.
directoryNodeId	The NodeId of the created directory Object.

Method Result Codes (defined in Call Service)

Result Code	Description
Bad_BrowseNameDuplicated	See OPC 10000-4 for a general description. A directory with the name already exists.
Bad_UserAccessDenied	See OPC 10000-4 for a general description.

Table 9 specifies the AddressSpace representation for the CreateDirectory Method.

Table 9 – CreateDirectory Method AddressSpace definition

Attribute	Value
BrowseName	CreateDirectory
References	NodeClass	BrowseName	DataType	TypeDefinition	ModellingRule
HasProperty	Variable	InputArguments	Argument[]	PropertyType	Mandatory
HasProperty	Variable	OutputArguments	Argument[]	PropertyType	Mandatory
Conformance Units
Base Info FileDirectoryType Base

CreateFile is used to create a new FileType Object organized by this Object. The created file can be written using the Write Method of the FileType.

Signature

CreateFile(

[in] String fileName

[in] Boolean requestFileOpen

[out] NodeId fileNodeId

[out] UInt32 fileHandle

);

Argument	Description
fileName	The name of the file to create. The name is used for the BrowseName and DisplayName of the file object and also for the file in the file system. For the BrowseName, the fileName is used for the name part of the QualifiedName. The namespace index is Server specific. For the DisplayName, the fileName is used for the text part of the LocalizedText. The locale part is Server specific.
requestFileOpen	Flag indicating if the new file should be opened with the Write and Read bits set in the open mode after the creation of the file. If the flag is set to True, the file is created and opened for writing. If the flag is set to False, the file is just created.
fileNodeId	The NodeId of the created file Object.
fileHandle	The fileHandle is returned if the requestFileOpen is set to True. The fileNodeId and the fileHandle can be used to access the new file through the FileType Object representing the new file. If requestFileOpen is set to False, the returned value shall be 0 and shall be ignored by the caller.

Method Result Codes (defined in Call Service)

Result Code	Description
Bad_BrowseNameDuplicated	See OPC 10000-4 for a general description. A file with the name already exists.
Bad_UserAccessDenied	See OPC 10000-4 for a general description.

Table 10 specifies the AddressSpace representation for the CreateFile Method.

Table 10 – CreateFile Method AddressSpace definition

Attribute	Value
BrowseName	CreateFile
References	NodeClass	BrowseName	DataType	TypeDefinition	ModellingRule
HasProperty	Variable	InputArguments	Argument[]	PropertyType	Mandatory
HasProperty	Variable	OutputArguments	Argument[]	PropertyType	Mandatory
Conformance Units
Base Info FileDirectoryType Base

Delete is used to delete a file or directory organized by this Object.

Signature

Delete(

[in] NodeId objectToDelete

);

Argument	Description
objectToDelete	The NodeId of the file or directory to delete. In the case of a directory, all file and directory Objects below the directory to delete are deleted recursively.

Method Result Codes (defined in Call Service)

Result Code	Description
Bad_NotFound	See OPC 10000-4 for a general description. A file or directory with the provided NodeId is not organized by this object.
Bad_InvalidState	See OPC 10000-4 for a general description. The file or directory is locked and thus cannot be deleted.
Bad_UserAccessDenied	See OPC 10000-4 for a general description.

Table 11 specifies the AddressSpace representation for the Delete Method.

Table 11 – Delete Method AddressSpace definition

Attribute	Value
BrowseName	Delete
References	NodeClass	BrowseName	DataType	TypeDefinition	ModellingRule
HasProperty	Variable	InputArguments	Argument[]	PropertyType	Mandatory
Conformance Units
Base Info FileDirectoryType Base

MoveOrCopy is used to move or copy a file or directory organized by this Object to another directory or to rename a file or directory.

Signature

MoveOrCopy(

[in] NodeId objectToMoveOrCopy

[in] NodeId targetDirectory

[in] Boolean createCopy

[in] String newName

[out] NodeId newNodeId

);

Argument	Description
objectToMoveOrCopy	The NodeId of the file or directory to move or copy.
targetDirectory	The NodeId of the target directory of the move or copy command. If the file or directory is just renamed, the targetDirectory matches the ObjectId passed to the method call.
createCopy	A flag indicating if a copy of the file or directory should be created at the target directory.
newName	The new name of the file or directory in the new location. If the string is empty, the name is unchanged.
newNodeId	The NodeId of the moved or copied object. Even if the Object is moved, the Server may return a new NodeId.

Method Result Codes (defined in Call Service)

Result Code	Description
Bad_BrowseNameDuplicated	See OPC 10000-4 for a general description. A file or directory with the name already exists.
Bad_NotFound	See OPC 10000-4 for a general description. A file or directory with the provided NodeId is not organized by this object.
Bad_InvalidState	See OPC 10000-4 for a general description. The file or directory is locked and thus cannot be moved or copied.
Bad_UserAccessDenied	See OPC 10000-4 for a general description.

Table 12 specifies the AddressSpace representation for the MoveOrCopy Method.

Table 12 – MoveOrCopy Method AddressSpace definition

Attribute	Value
BrowseName	MoveOrCopy
References	NodeClass	BrowseName	DataType	TypeDefinition	ModellingRule
HasProperty	Variable	InputArguments	Argument[]	PropertyType	Mandatory
HasProperty	Variable	OutputArguments	Argument[]	PropertyType	Mandatory
Conformance Units
Base Info FileDirectoryType Base

This ObjectType defines a type for the representation of temporary file transfers. It is formally defined in Table 13. The Methods GenerateFileForRead or GenerateFileForWrite generate a temporary FileType Object that is not browsable in the AddressSpace and can only be accessed with the NodeId and FileHandle returned by the Methods in the same Session. This Object is used to transfer the temporary file between OPC UA Client and Server.

Table 13 – TemporaryFileTransferType

Attribute	Value
BrowseName	TemporaryFileTransferType
IsAbstract	False
References		NodeClass	BrowseName	DataType	TypeDefinition	Modelling Rule
Subtype of the BaseObjectType defined in OPC 10000-5
HasProperty		Variable	ClientProcessingTimeout	Duration	PropertyType	Mandatory
HasComponent		Method	GenerateFileForRead	Defined in 4.4.3		Mandatory
HasComponent		Method	GenerateFileForWrite	Defined in 4.4.4		Mandatory
HasComponent		Method	CloseAndCommit	Defined in 4.4.5		Mandatory
HasComponent		Object	<TransferState>		FileTransferStateMachineType	OptionalPlaceholder
Conformance Units
Base Info TemporaryFileTransferType Base

The Property ClientProcessingTimeout defines the maximum time in milliseconds the Server accepts between Method calls necessary to complete a file read transfer or a file write transfer transaction. This includes the Method calls to read or write the file content from the virtual temporary FileType Object. If the Client exceeds the timeout between Method calls, the Server may close the file and cancel the corresponding transfer transaction. Any open temporary transfer file shall be deleted if the Session used to create the file is no longer valid.

The TransferState Objects are used to expose the state of a transfer transaction in the case that the preparation of a file for reading or the processing of the file after writing completes asynchronous after the corresponding Method execution. If the transactions are completed when the Method is returned, the optional TransferState Objects are not available. A Server may allow more than one parallel read transfer. A Server may not allow more than one write transfer or a parallel read and writer transfer.

The sequence of Method calls necessary to execute a read file transfer transaction is illustrated in Figure 2.

Figure 2 – Read file transfer example sequence

The read file transfer transaction is started with the Method GenerateFileForRead defined by the TemporaryFileTransferType. After a successful call of this Method, the Client reads the file content by calling the Method Read defined by the FileType until the whole file is transferred from the Server to the Client. The transaction is completed by calling the Method Close defined by the FileType.

The sequence of Method calls necessary to execute a write file transfer transaction is illustrated in Figure 3.

Figure 3 – Write file transfer example sequence

The write file transfer transaction is started with the Method StartWriteTransfer defined by the TemporaryFileTransferType. After a successful call of this Method, the Client writes the file content by calling the Method Write defined by the FileType until the whole file is transferred from the Client to the Server. The transaction is completed by calling the Method CloseAndCommit defined by the TemporaryFileTransferType. If the Client wants to abort the operation it uses the Close Method of the temporary FileType Object.

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 OptionSetUsed to provide a bit mask for file content selection String Can be used to provide a string filter or a regular expression StructureCan be used to provide a structure with create settings e.g. to create a report EnumerationCan 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.

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

GenerateFileForWrite is used to start the write file transaction. A successful call of this Method creates a temporary FileType Object and returns the NodeId of this Object and the file handle to access the Object.

Signature

GenerateFileForWrite(

[in] BaseDataTypegenerateOptions

[out] NodeId fileNodeId

[out] UInt32 fileHandle

);

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 OptionSetUsed to provide a bit mask for file use selection StructureCan be used to provide a structure with create settings e.g. firmware update settings EnumerationCan be used to provide a list of options like file handling options
fileNodeId	NodeId of the temporary file.
fileHandle	The fileHandle of the opened TransferFile. The fileHandle can be used to access the TransferFile Methods Write and Close.

Method Result Codes (defined in Call Service)

Result Code	Description
Bad_UserAccessDenied	See OPC 10000-4 for a general description.

Table 15 specifies the AddressSpace representation for the GenerateFileForWrite Method.

Table 15 – GenerateFileForWrite Method AddressSpace definition

Attribute	Value
BrowseName	GenerateFileForWrite
References	NodeClass	BrowseName	DataType	TypeDefinition	ModellingRule
HasProperty	Variable	InputArguments	Argument[]	PropertyType	Mandatory
HasProperty	Variable	OutputArguments	Argument[]	PropertyType	Mandatory
Conformance Units
Base Info TemporaryFileTransferType Base

CloseAndCommit is used to apply the content of the written file and to delete the temporary file after the completion of the transaction.

Signature

CloseAndCommit(

[in] UInt32 fileHandle

[out] NodeId completionStateMachine

);

Argument	Description
fileHandle	The fileHandle used to write the file.
completionStateMachine	If the processing of the file is completed asynchronous, the parameter returns the NodeId of the corresponding FileTransferStateMachineType Object. If the processing of the file is already completed, the parameter is null. If a FileTransferStateMachineType Object NodeId is returned, the processing is in progress until the TransferState changed to Idle.

Method Result Codes (defined in Call Service)

Result Code	Description
Bad_UserAccessDenied	See OPC 10000-4 for a general description.

Table 16 specifies the AddressSpace representation for the CloseAndCommit Method.

Table 16 – CloseAndCommit Method AddressSpace definition

Attribute	Value
BrowseName	CloseAndCommit
References	NodeClass	BrowseName	DataType	TypeDefinition	ModellingRule
HasProperty	Variable	InputArguments	Argument[]	PropertyType	Mandatory
HasProperty	Variable	OutputArguments	Argument[]	PropertyType	Mandatory
Conformance Units
Base Info TemporaryFileTransferType Base

The states of the file transfer state machine are shown in Figure 4.

Figure 4 – File transfer States

The FileTransferStateMachineType and the related type are illustrated in Figure 5.

Figure 5 – FileTransferStateMachineType

This ObjectType defines the StateMachine for asynchronous processing of temporary file transfers. It is formally defined in Table 17. The transitions are formally defined in Table 19.

Table 17 – FileTransferStateMachineType

Attribute	Value
BrowseName	FileTransferStateMachineType
IsAbstract	False
References		NodeClass	BrowseName	DataType	TypeDefinition	Modelling Rule
Subtype of the FiniteStateMachineType defined in B.4.5.
HasComponent		Object	Idle		InitialStateType
HasComponent		Object	ReadPrepare		StateType
HasComponent		Object	ReadTransfer		StateType
HasComponent		Object	ApplyWrite		StateType
HasComponent		Object	Error		StateType
HasComponent		Object	IdleToReadPrepare		TransitionType
HasComponent		Object	ReadPrepareToReadTransfer		TransitionType
HasComponent		Object	ReadTransferToIdle		TransitionType
HasComponent		Object	IdleToApplyWrite		TransitionType
HasComponent		Object	ApplyWriteToIdle		TransitionType
HasComponent		Object	ReadPrepareToError		TransitionType
HasComponent		Object	ReadTransferToError		TransitionType
HasComponent		Object	ApplyWriteToError		TransitionType
HasComponent		Object	ErrorToIdle		TransitionType
HasComponent		Method	Reset	Defined in 4.4.7		Mandatory
Conformance Units
Base Info TemporaryFileTransferType Base

The component Variables of the FileTransferStateMachineType have additional Attributes defined in Table 18.

Table 18 – FileTransferStateMachineType Attribute values for child Nodes

Source Path	Value Attribute
Idle StateNumber	1
ReadPrepare StateNumber	2
ReadTransfer StateNumber	3
ApplyWrite StateNumber	4
Error StateNumber	5
IdleToReadPrepare TransitionNumber	12
ReadPrepareToReadTransfer TransitionNumber	23
ReadTransferToIdle TransitionNumber	31
IdleToApplyWrite TransitionNumber	14
ApplyWriteToIdle TransitionNumber	41
ReadPrepareToError TransitionNumber	25
ReadTransferToError TransitionNumber	35
ApplyWriteToError TransitionNumber	45
ErrorToIdle TransitionNumber	51

Table 19 – FileTransferStateMachineType Additional References

SourceBrowsePath	References	IsForward	TargetBrowsePath
IdleToReadPrepare	FromState	True	Idle
	ToState	True	ReadPrepare
	HasEffect	True	TransitionEventType
ReadPrepareToReadTransfer	FromState	True	ReadPrepare
	ToState	True	ReadTransfer
	HasEffect	True	TransitionEventType
ReadTransferToIdle	FromState	True	ReadTransfer
	ToState	True	Idle
	HasEffect	True	TransitionEventType
IdleToApplyWrite	FromState	True	Idle
	ToState	True	ApplyWrite
	HasEffect	True	TransitionEventType
ApplyWriteToIdle	FromState	True	ApplyWrite
	ToState	True	Idle
	HasEffect	True	TransitionEventType
ReadPrepareToError	FromState	True	ReadPrepare
	ToState	True	Error
	HasEffect	True	TransitionEventType
ReadTransferToError	FromState	True	ReadTransfer
	ToState	True	Error
	HasEffect	True	TransitionEventType
ApplyWriteToError	FromState	True	ApplyWrite
	ToState	True	Error
	HasEffect	True	TransitionEventType
ErrorToIdle	FromState	True	Error
	ToState	True	Idle
	HasEffect	True	TransitionEventType

Reset is used to reset the Error state of a FileTransferStateMachineType Object.

Signature

Reset();

Table 20 specifies the AddressSpace representation for the Reset Method.

Table 20 – Reset Method AddressSpace definition

Attribute	Value
BrowseName	Reset
References	NodeClass	BrowseName	DataType	TypeDefinition	ModellingRule
Conformance Units
Base Info TemporaryFileTransferType Base

_____________