The main objective of this companion standard is to have an Information Model that results in a clearly defined and structured CNC data interface. That means that both data items and its composition are specified. Manufacturer and use case specific extensions shall be possible.
Regarding the data elements standard OPC UA Variable types shall be used as far as possible. There are two main categories of data items present: unit based items (e.g. position data in mm or inch) and items without unit (e.g. state data). Unit based items shall be realized as AnalogItemTypes, other data as DataItemTypes. Units shall be used as described in OPC 10000-8.
Regarding the structure of the CNC data interface it is intended to realize flat hierarchies. However, multiple referencing of Objects shall be used for exposing the assignment of components within the hardware or software system.
ObjectTypes shall be derived as far as possible from hardware and software components of a CNC system.