If the text part of a value of DataType LocalizedText, like the Manufacturer or the Model of a Machine, is language neutral, i.e. it is the same in all languages, the locale of the LocalizedText shall be null or an empty string.
If the information for optional nodes (e.g., Properties) is not available and the access is read-only, the optional Node shall not be provided.
If the content of optional nodes is writable, i.e. it can be provided by end-users, system integrators, etc., it is desirable to provide the Nodes to allow the usage of them.
Using the MachineryBuildingBlocks Object may lead to several paths to the same Node in a TypeDefinition (see for example Figure 7). When instantiating such a TypeDefinition it is recommended to keep this approach and let several References lead to the same Node, rather than duplicating the Node. In Figure 8, an example is given. The X:SpecificMachineType is referencing the 2:Identification Object directly and from the MachineryBuildingBlocks Object. The Object Machine123 of X:SpecificMachineType is doing the same, and not duplicating the 2:Identification Object (which would be an allowed instantiation, see OPC 10000-3). This avoids unnecessary Nodes and potentially inconsistent data, like in Object Machine124.
