Errata exists for this version of the document.

Following are sub-types of SystemEventType that will be generated in response to a Refresh Methods call. They are illustrated in Figure 23.

Figure 23 – Refresh Related Event Hierarchy

This EventType is used by a Server to mark the beginning of a Refresh Notification cycle. Its representation in the AddressSpace is formally defined in Table 99.

Table 99 – RefreshStartEventType definition

Attribute	Value
BrowseName	RefreshStartEventType
IsAbstract	True
References	NodeClass	BrowseName	DataType	TypeDefinition	ModellingRule
Subtype of the SystemEventType defined in OPC 10000-5, i.e. it has HasProperty References to the same Nodes.

This EventType is used by a Server to mark the end of a Refresh Notification cycle. Its representation in the AddressSpace is formally defined in Table 100.

Table 100 – RefreshEndEventType definition

Attribute	Value
BrowseName	RefreshEndEventType
IsAbstract	True
References	NodeClass	BrowseName	DataType	TypeDefinition	ModellingRule
Subtype of the SystemEventType defined in OPC 10000-5, i.e. it has HasProperty References to the same Nodes.

This EventType is used by a Server to indicate that a significant change has occurred in the Server or in the subsystem below the Server that may or does invalidate the Condition state of a Subscription. Its representation in the AddressSpace is formally defined in Table 101.

Table 101 – RefreshRequiredEventType definition

Attribute	Value
BrowseName	RefreshRequiredEventType
IsAbstract	True
References	NodeClass	BrowseName	DataType	TypeDefinition	ModellingRule
Subtype of the SystemEventType defined in OPC 10000-5, i.e. it has HasProperty References to the same Nodes.

When a Server detects an Event queue overflow, it shall track if any Condition Events have been lost, if any Condition Events were lost, it shall issue a RefreshRequiredEventType Event to the Client after the Event queue is no longer in an overflow state.