The CreateMonitoredItem Service allows specifying a filter for each MonitoredItem. The MonitoringFilter is an extensible parameter whose structure depends on the type of item being monitored. The parameterTypeIds are defined in Table 145. Other types can be defined by additional parts of this multi-part specification or other specifications based on OPC UA. The ExtensibleParameter type is defined in 7.17.

Each MonitoringFilter may have an associated MonitoringFilterResult structure which returns revised parameters and/or error information to Clients in the response. The result structures, when they exist, are described in the section that defines the MonitoringFilter.

Table 145 – MonitoringFilter parameterTypeIds

Symbolic Id	Description
DataChangeFilter	The change in a data value that shall cause a Notification to be generated.
EventFilter	If a Notification conforms to the EventFilter, the Notification is sent to the Client.
AggregateFilter	The Aggregate and its intervals when it will be calculated and a Notification is generated.