CNC Systems Information Model
Computerized Numerical Control (CNC) systems are used to control machine tools and machining centers. The CNC system is mainly responsible for generating a relative movement between a tool (e.g cutting tool) and a workpiece. Therefore, the CNC system implements functionality to provide setpoints to a machine tool’s drives that realize the generated movement physically.
CNC systems are in most cases executed in combination with Programmable Logic Controllers (PLC). Whereas the CNC is responsible for the tool path generation, the PLC implements auxiliary functionality (mostly logical operations like activating lubrication at a certain time) and controls the peripheral devices.
Main objective of the OPC UA companion standard for CNC systems 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. However, manufacturer- and use case-specific extensions are possible as well.
The focus is on data that is situated within the CNC kernel but not within the PLC of a CNC system. Hence, this Information Model addresses applications like HMIs, PDA/MDA systems, diagnosis and monitoring applications, but not necessarily MES or ERP systems as the two latter ones mostly need summarized data.
CNC Systems Capabilities
Discovery ID: CNC
Understand and support the OPC UA for CNC Information Model. Support the interface structure and the access of all data provided by the CNC system, namely parameters, state data, process and command data, and alarm notifications that are defined by this companion standard.
- Setup: The CNC data interface provides data that can be used for setting up a production system controlled by a CNC. This refers first of all to production commissioning data (e.g. job description, tool data etc.) but implies to a certain extent as well CNC configuration data (e.g. axis parameters, cycle time etc.), as needed for engineering.
- Operation: The CNC data interface may be used for operating a production system controlled by a CNC and therefore serves as a connection point for user interfaces.
- Observation: The CNC data interface may be used for observing a production system controlled by a CNC and therefore serves as a connection point for monitoring and diagnosis applications and for user interfaces.
CNC Data Interface Client Facet
Discovery ID: CNC
Support the file access mechanisms. Files are transferred from the Maschine Interface to the CNC kernel or the PLC, maybe as well to the drives and peripheral devices holding configuration data (e.g. tool parameters) or process information in form of part programs or similar.
CNC systems handle several types of files, e.g. configuration and part program files.
File Access Server Facet
CNC Data Interface Client Facet (Client File Access Conformance Unit)