NodeClass
i.e.: ObjectType
, DataType
, ReferenceType
, VariableType
(Section Address Space and Address Space Model). The main role of the types represented by the above NodeClass
es is to provide a description of the Address Space structure and to allow clients to use this knowledge to navigate to the desired information in the Address Space exposed by the server. In other words, this way the clients obtain the definition of the data (meta-data) using the following two concepts:NodeClass
– as a formal description of the node defining the allowed attributes and references.NodeClass
plays a role similar to the shape of a puzzle piece and the represented information is similar to the picture on the piece. Both are needed to enable us to see the final picture. In the above simplification we have lost that the OPC UA Address Space is capable of displaying movies, and not just static pictures.