The FileTransfer Object is of type TemporaryFileTransferType as defined in OPC 10000-5. It is used to create temporary files for download and upload of the Software Package. See 8.7 for the definition of a standard packaging format.

In the TemporaryFileTransferType type the GenerateFileForRead and GenerateFileForWrite Methods take an unspecified generateOptions Parameter. For the FileTransfer Object an Enumeration of type SoftwareVersionFileType is used for this Parameter. It is used to select the file to upload or download. All allowed values are defined in Table 112. Additional Result Codes of the GenerateFileForRead and GenerateFileForWrite Methods are specified in Table 80.

Table 80 – TemporaryFileTransferType Result Codes

Result Code	Description
Bad_InvalidState	This result code is only used with DirectLoading.f the PrepareForUpdate is available, the UpdateBehavior requires preparation and the PrepareForUpdate state machine is not in the state PreparedForUpdate.
Bad_NotFound	If there is no file to read from the device.
Bad_NotSupported	If the device does not support to upload / download of the Software Package.

For all errors that occur during the file transfer the ErrorMessage Variable should provide an error message for the user.

It is implementation dependent which version (see SoftwareVersionFileType in 8.5.1) is readable and which one is writable. Additional restrictions are defined in the concrete sub-types of PackageLoadingType.