Overview

The TwinCAT OPC UA Nodeset Editor is an engineering tool for creating and editing OPC UA nodeset files, which are used in particular for companion specifications. With the help of the editor, you can map existing companion specifications or your own information models on your Beckhoff controller and link them with data points from the PLC.

When developing a machine application, there are often requirements for the structure of the OPC UA namespace of a machine to be mapped. In this case, it is necessary to establish conformity to a companion specification or a customer-specific information model so that the machine can be integrated as smoothly as possible into an existing and standardized environment.

The TwinCAT OPC UA Nodeset Editor is the graphical solution to meet this challenge. It allows:

• Loading nodeset files from companion specifications or custom information models.
• Creation of simple user-defined nodeset files.
• Convenient linking of objects from the controller with those from a loaded or created nodeset.
• Using the nodeset for new and existing machines using the TwinCAT OPC UA Server (TF6100).

Use cases

The TwinCAT OPC UA Nodeset Editor supports the user in the implementation of requirements regarding companion specifications by providing a graphical user interface that enables the import of nodesets. However, even without requirements for a specific companion specification, the TwinCAT OPC UA Nodeset Editor may be a useful tool and assist in the following use cases.

Creation of custom server address space

Even before companion specifications became widespread, there were initial requests to make information from the PLC available on the TwinCAT OPC UA Server according to a defined structure. By default, the server uses the IEC61131-3 information model to provide variables from the PLC via OPC UA. However, sometimes this data representation on the server is not desired and there were requests for a "simple modeling option for folders and simple data types". This use case can be addressed with the help of this product.

Linking variables from existing nodesets

Nodesets that have been created with a third-party tool, such as the UA Modeler (https://www.unified-automation.com), can be imported into the TwinCAT OPC UA Server. However, since third-party tools do not have any variable information from a TwinCAT control program, the TwinCAT OPC UA Nodeset Editor can be used instead. The existing nodesets can be imported into the graphical user interface of the Nodeset Editor and linked there with PLC variables using the TwinCAT Target Browser. The resulting nodeset file can then be deployed to the TwinCAT OPC UA Server.

Creating instance nodesets from a companion specification

Importing companion specifications and creating instances from the data and object types within is required if a machine has to be equipped with a standardized interface that has been defined by the companion specification. The TwinCAT OPC UA Nodeset Editor enables the instantiation of such data and object types and the subsequent linking of the instances with variables from the TwinCAT PLC.

Workflow

The workflow when using the TwinCAT OPC UA Nodeset Editor to create a nodeset and the subsequent export to the TwinCAT OPC UA Server can be illustrated as follows.

In step (1) the nodeset file (the "companion specification") is imported into the TwinCAT OPC UA Nodeset Editor. This means that the data types defined in the file are available in the editor environment and can be used for project planning.

In step (2) and (3) the project engineering takes place, i.e. objects ("instances") are created from the data types and linked with variables from the PLC.

In step (4) the generated project is imported into the TwinCAT OPC UA Server so that it can provide the generated information model in its address space.