The parameter SelectedFieldsdefines the selection of Eventfields contained in the DataSetgenerated for an Eventand sent through the DataSetWriter. The SimpleAttributeOperand DataTypeis defined in OPC 10000-4. The DataTypeof the selected Eventfield in the EventTypedefines the DataTypeof the DataSetfield. Eventfields can be null or the field value can be a StatusCode. The encoding of EventbasedDataSetMessagesshall be able to handle these cases. ExtensionFieldsdefined for the instance of the PublishedEventsTypecan be included in the SelectedFieldsby specifying the PublishedEventsType NodeIdas typeId in the SimpleAttributeOperandand the BrowseNameof the extension field in the browsePathof the SimpleAttributeOperand.

The index into the list of entries in the SelectedFieldshas an important role for Subscribers. It is used as handle to reference the Eventfield in DataSetMessagesreceived by Subscribers. The index may change after configuration changes. Changes are indicated by the ConfigurationVersionand applications working with the index shall always check the ConfigurationVersionbefore using the index. If a change of the SelectedFieldsadds additional fields, the MinorVersionof the ConfigurationVersionshall be updated. If a change of the SelectedFieldsremoves fields, the MajorVersionof the ConfigurationVersionshall be updated. The ConfigurationVersionDataTypeand the rules for setting the version are defined in 6.2.2.1.5.