The primary objective of the OPC UA AddressSpaceis to provide a standard way for Serversto represent Objectsto Clients. The OPC UA Object Model has been designed to meet this objective. It defines Objectsin terms of Variablesand Methods. It also allows relationships to other Objectsto be expressed. Figure 2illustrates the model.


Figure 2– OPC UA Object Model

The elements of this model are represented in the AddressSpaceas Nodes. Each Nodeis assigned to a NodeClassand each NodeClassrepresents a different element of the Object Model. Clause 4.9defines the NodeClassesused to represent this model.