6 Systems concepts

6.3 OPC UA Servers

6.3.5 Subscription entities

6.3.5.1 MonitoredItems

MonitoredItems are entities in the Server created by the Client that monitor AddressSpace Nodes and their real-world counterparts. When they detect a data change or an event/alarm occurrence, they generate a Notification that is transferred to the Client by a Subscription.

6.3.5.2 Subscriptions

A Subscription is an endpoint in the Server that publishes Notifications to Clients. Clients control the rate at which publishing occurs by sending Publish Messages.