The Write or HistoryUpdate Services in this Service Set for Servers that support auditing may generate audit entries and shall generate audit Events for both successful and failed Service invocations. These Services shall generate an audit Event of type AuditUpdateEventType or subtypes of it. In particular, the Write Service shall generate an audit event of type AuditWriteUpdateEventType or a subtype of it. The HistoryUpdate Service shall generate an audit Event of type AuditHistoryUpdateEventType or a subtype of it. Three subtypes of AuditHistoryUpdateEventType are defined as AuditHistoryEventUpdateEventType, AuditHistoryValueUpdateEventType and AuditHistoryDeleteEventType. The subtype depends on the type of operation being performed, historical event update, historical data value update or a historical delete. See OPC 10000-5 for the detailed assignment of the SourceNode, the SourceName and additional parameters. For the failure case the Message for Events of this type should include a description of why the Service failed. The additional parameters should include the details of the request.

The Read and HistoryRead Services may generate audit entries and audit Events for failed Service invocations. These Services should generate an audit Event of type AuditEventType or a subtype of it. See OPC 10000-5 for the detailed assignment of the SourceNode, SourceName and additional parameters. The Message for Events of this type should include a description of why the Service failed.

For Clients that support auditing, accessing the Write or HistoryUpdate services in the Attribute Service Set shall generate audit entries for both successful and failed invocations of the Service. Invocations of the other Services in this Service Set may generate audit entries. All audit entries should be setup prior to the actual Service invocation, allowing the invocation to contain the correct audit record id.