Device-types can come in different device-type variants. Just as a car model (like a Toyota Corolla) is offered in different trims (LE, SE, XLE) and paint colors, a device-type variant represents a specific configuration of the base device-type, customized with distinct attributes for its visual appearance. Furthermore, each device-type variant is linked to a specific sales item, identified by a unique item number.
Note that the actual physical, electronic, and digital characteristics of a device are determined by the components actually built into it, not by the device-type or device-type variant. In other words, the digital characteristics cannot be inferred solely from the device-type or its variant. To draw a parallel, knowing the trim level of a Toyota Corolla (e.g., SE) doesn’t reveal the horsepower unless you know the specific engine installed. Similarly, for a device (of a specific device-type and device-type variant), the actual characteristics can only be determined by knowing the specific components used, unless the device-type is limited to a single fixed configuration of component-types.
Each device-type has at least one but may have multiple variants. For each device-type there is one variant defined as the default variant. This variant's attributes can be used by clients if they cannot infer the exact variant for some reason.
The Catalog Service defines the available variants of a device-type. The Digital Twin Service stores a reference to the actual device-type variant for each device. The device-type variant of a specific device is written when the digital twin of a device is created and is immutable thereafter.
Table 4 shows the attributes for device-type variants.
Attribute |
Description |
|---|---|
Name |
Mandatory A human-readable name for the device-type variant, provided in a single language. E.g. Black disinfect dispenser. |
Image |
The symbolic image that pictures this variant. Mandatory. Images are stored and delivered in different resolutions. |
Item number |
Mandatory for variants of regular device types. Not set for system device-types. The item-no (usually used in sales) for this device type item. |
Table 4: Attributes of device-type variants stored with the Catalog Service
