Figure D.28 shows the FunctionalEntity for a simple temperature monitor based on the Raspberry Pi Sense HAT (see Figure D.5). The FunctionalEntity provides the output Variable Temperature, indicating the current temperature. It also includes a Variable EngineeringUnit (e.g., °C, °F, °K…). This configuration variable allows the selection of the engineering unit for the Temperature.

Figure D.28 – Sample FunctionalEntity for a simple temperature monitor

While using the Temperature, the EngineeringUnit for the Temperature should not change. To achieve this behaviour, the ControlGroup MonitorControl is provided. The EngineeringUnit is contained in the ListToRestrict to ensure that changes are restricted to the owner of the ControlGroup. Temperature is contained in the ListOfRelated to indicate that Temperature is part of the ControlGroup.