.NET Based OPC UA Client/Server SDK


The OPC UA Client SDK defines APIs which the Application Developer can use to communicate with an OPC UA Server. There are numerous helper classes which store different types of information; however, the primary classes which the Application Developer works with are shown in the figure below.


The ApplicationInstanceBase manages the application configuration and is associated with one or more Session instances. It also can take care of installing or uninstalling the Application.

A Session represents a connection with a single Server. It maintains a list of active Subscriptions in addition to a node CacheManager and an information ModelManager.

A Subscription represents an active Subscription with a Server. A Subscription is owned by one Session and will have one or more MonitoredItems. MonitoredItems are used to monitor data or events produced by individual nodes in the Server address space.

The CacheManager maintains a local cache of nodes and their attributes. It is used to quickly find display texts or to follow type hierarchies when working with information returned by the Server.

The ModelManager provides access to the Server via mapped objects representing pieces of the information model exposed by the Server. These objects allow the Application Programmer to read, write and subscribe to multiple nodes at via an intuitive object oriented API defined them.