Table 165defines the NotificationDataparameter used for data change notifications. This structure contains the monitored data items that are to be reported. Monitored data items are reported under two conditions:

  1. if the MonitoringModeis set to REPORTING and a change in value or its status (represented by its StatusCode) is detected;
  2. if the MonitoringModeis set to SAMPLING, the MonitoredItemis linked to a triggering item and the triggering item triggers.

See 5.12for a description of the MonitoredItem Serviceset, and in particular the MonitoredItem modeland the Triggering model.

After creating a MonitoredItem,the current value or status of the monitored Attribute shall be queued without applying the filter. If the current value is not available after the first sampling interval the first Notificationshall be queued after getting the initial value or status from the data source.

Table 165– DataChangeNotification

Name

Type

Description

DataChangeNotification

structure

Data change Notificationdata.

monitoredItems []

MonitoredItem Notification

The list of MonitoredItemsfor which a change has been detected. This structure is defined in-line with the following indented items.

clientHandle

IntegerId

Client-supplied handle for the MonitoredItem. The IntegerIdtype is defined in 7.19

Value

DataValue

The StatusCode, value and timestamp(s) of the monitored Attributedepending on the sampling and queuing configuration.

If the StatusCodeindicates an error then the value is to be ignored.

If not every detected change has been returned since the Server's queue buffer for the MonitoredItemreached its limit and had to purge out data and the size of the queue is larger than one, the Overflowbit in the DataValue InfoBitsof the statusCodeis set.

DataValueis a common type defined in 7.11.

diagnosticInfos []

DiagnosticInfo

List of diagnostic information. The size and order of this list matches the size and order of the monitoredItemsparameter. There is one entry in this list for each Nodecontained in the monitoredItemsparameter. This list is empty if diagnostics information was not requested or is not available for any of the MonitoredItems. DiagnosticInfois a common type defined in 7.12.