Equivalent WoT TD definition

Thing

Description

In OPC UA Objects are used to represent systems, system components, real-world objects and software objects. Objects are defined using the Object NodeClass.

In WoT Thing Description, a Thing represents real-world objects and software objects and their elements through interaction affordances (properties and actions).

It is recommended for each UA Object defined under the UA Root to create an individual TD. The mechanism may also facilitate the creation of individual TDs for nested UA Object nodes, provided these nodes contain a reasonable number of nested UA Variables or Methods, or possess a self-contained context.

By default, nested UA Objects are not directly transformed into TDs. Instead, their nested UA Variables and Methods are aggregated into a single TD representing the top-level UA Object.

Example in OPC UA (as nodeset)

<UAObject NodeId="ns=3;i=5001" BrowseName="3:PaintingRobot_1" ParentNodeId="ns=2;i=5002"> <DisplayName>Painting Robot</DisplayName> ….

Transformed usage in a TD definition (as snippet)

{

"@context":"https://www.w3.org/2022/wot/td/v1.1",

"@type": ["Thing"],

"title": "Painting Robot",

"base": "opc.tcp://opcuademo.com:4840",

"securityDefinitions": { "auto_sc": { "scheme": "auto" } },

"security": "auto_sc",

…

Alternative:

{ "@context":"https://www.w3.org/2022/wot/td/v1.1",

"@type": ["Thing", "uav:object"], "title": "Painting Robot", "uav:browseName": "3:PaintingRobot_1", "base": "opc.tcp://opcuademo.com:4840",

"securityDefinitions": { "auto_sc": { "scheme": "auto" } },

"security": "auto_sc", …