OT operators want to communicate with non-OPC UA assets for on-prem or cloud analytics. To do so, a unified data model like OPC UA is desirable as well as a clear description of the asset’s communication protocol and endpoint. Web of Things (WoT) Thing Descriptions (TD) provide such a description and many industrial asset vendors already provide a WoT TD for their products. Secondly, WoT already defines a protocol binding specification for protocols like Modbus or HTTP.
Non-OPC UA assets must be mapped to OPC UA in a (preferably) automated fashion using industrial connectivity software. To achieve this automation, a machine-readable schema fully describing the asset is necessary. For interoperability, a standardized configuration interface, based on OPC UA, is desirable. This can be achieved by specifying a number of OPC UA Methods which are provided in this specification. The industrial connectivity application used to communicate with the asset can then implement these OPC UA Methods to map the asset to OPC UA.