Information Modeling: Concepts

Abstract

The fundaments of OPC UA are data transport and information modeling. Compared to Classic OPC, the data transport was changed to state-of-the-art, platform-independent, secure, and reliable technologies and the capabilities to model information are highly improved. In Classic OPC, only “pure” data is provided, for example, the temperature measured by a temperature sensor. The only information available to understand the semantic of the provided data is the tag name and some rudimentary information like the engineering unit of the measured value. OPC UA provides more powerful possibilities exposing the semantic of the provided data. In addition to the data provided by Classic OPC, it allows exposing information like that the measured temperature is provided by a specific type of sensor device and allows to expose in a type hierarchy what kind of devices are supported. Thereby, OPC UA clients can get the information that they are dealing with the same kind of device at different places. By exposing much more semantics, OPC UA servers allow clients to process highly sophisticated tasks by interpreting the semantic of the provided data. That includes the automated integration of data provided by an OPC UA server as well as engineering an OPC UA server from a generic OPC UA client.