Terminology

Nodeset

A nodeset is a file that formally describes an OPC UA information model. Nodeset files are usually XML-based and must be structured according to an XML schema definition. Nodesets are used for processing information models with the computer. A nodeset defines nodes, their attributes, and references. A reference can point to nodes in the same document as well as to nodes outside the file. OPC UA itself defines some central information models with corresponding nodesets, for example:

Particularly noteworthy is the "Core" model, whose nodeset is also colloquially referred to as the "Base" nodeset. The core model usually serves as a basis for other information models and describes the basic data types that are available in OPC UA.

Companion specifications

Although the existing OPC UA information models are already applicable in many industries, it is possible to create own information models to meet specific requirements. For this purpose, companies and organizations join forces to define industry-specific models, so-called "companion specifications". Such companion specifications are available, for example, for the packaging industry (PackML) or for plastics processing (EUROMAP).

Further information on this topic can be found on the OPC Foundation website.

Node

A node is a fundamental part of the address space of a server and represents an object, variable or method. Even data and object types are represented on the server’s address space as a node.