Elements

The probe breaks event data down into tokens and parses them into elements. Elements are used to assign values to ObjectServer fields; the field values contain the event details in a form that the ObjectServer understands.

The following table describes the elements that the probe generates. Not all the elements described are generated for each event; the elements that the probe generates depends upon the event type.

Table 1. Elements

Element name

Element description

$ClientHandle

This element contains the user-supplied identifier for a monitored item. <RequestedParameters> describes the client handle and its use.

$EventId

This element contains the identifier of the event which is the subject of an event notification.

$EventType

This element identifies the type of event which is the subject of an event notification.

$InnerStatusCode

This element contains the status code returned from the underlying system used to complete the execution of an OPC UA service.

$MessageText

This element contains the message text associated with an event notification.

$NodeId

This element identifies the node in the server namespace where a data change has occurred.

$OpcUaEventType

This element identifies the type of OPC UA event that has occurred. This element can have the following values:

  • DataChangeNotification
  • EventNotificationList
  • StatusChangeNotification

$Severity

This element contains the severity code associated with an event notification. The code is a number between 1 and 1000. The higher the number the more severe the event.

$SourceName

This element contains the name of the node in the server namespace that generated an event notification.

$SourceNode

This element contains the identifier of the node in the server namespace that generated an event notification.

$SourceTimestamp

This element contains the Coordinated Universal Time (UTC) that identifies when a change in a data value occurred at the source. The time is expressed as the number of 100 nanosecond intervals since 1 January 1601.

$StatusCode

This element contains the new status code that triggered the occurrence of a status change notification.

$Time

This element contains the time when an event notification occurred.

$Value

This element contains the value of the data element that is the subject of a data change notification.