事件过滤查询语言

OPC Day International 2024—Event Filter Query LanguageJulius PfrommerFlorian DüwelOPC UA EventsBackgroundJune 25, 2024© Fraunhofer IOSBPage 2▪Events are emitted by Objects in the information model▪Events bubble upwards in the information model and are again emitted by each parent Object▪OPC UA Events are “temporary OPC UA Objects” with the properties of the Event (fields)▪BaseEventType defines standard properties, such as the Event‘s severity▪Custom subtypes for additional properties▪Clients access Events via the OPC UA Subscription mechanism▪MonitoredItem attaches to an Object and listens for the Events emitted by the Object▪MonitoredItem defines an EventFilter▪Which fields to transmit (Select-Clause, required)▪Which event instances to transmit (Where-Clause, optional)Example EventTypeExampleEventFilterWhere-ClauseMuch toohardforend-users todefineJune 25, 2024© Fraunhofer IOSBPage 3Corresponding ContentFilter Data TypeLogical Structure of the ContentFilter▪Users have to supply this “b