Information Modeling: Example and Best Practice
In Chap. 2 you learned the concepts of modeling information in OPC UA. In this chapter we will tighten your knowledge by looking at a concrete example showing how to apply the concepts. We will start with a simple scenario only exposing data similar to Classic OPC. Then we will go forward by adding type information, multiple references, etc. to demonstrate the full power of information modeling in OPC UA. This already shows a way of how to migrate existing Classic OPC applications to OPC UA with respect to the modeling. However, in Chap. 10, we talk about more details on how to migrate from Classic OPC to OPC UA.
In the example, we target an application scenario typical for Classic OPC applications. However, in the second part of this chapter we will generalize the example by looking at some general best practices on how to model information in OPC UA. In the example, we will not consider standard Information Models other than using types of the base Information Model. In Chap. 4, we will introduce standard Information Models. When modeling your information, you should consider using those Information Models and extend them rather than creating your own Information Model from scratch when this is appropriate in your domain.
The notation used in the example to expose details on the Information Model is described in Appendix A of this book. The Appendix does not only describe the notation but also discusses its relation to UML.