6.2.4 UI

The UI (user interface) is the interface between the customer and the system. The UI is only related to the final customer interaction. Technical user interfaces for configuration or maintenance of the machine are not part of this component and not addressed by this specification. A Vending Machine according to this specification needs to have at least one UI, but may have several UIs.

The UI provides its interface by implementing an instance of the UIType (shown in Figure 13, defined in 7.23). The UI requires OPC UA Client functionality to access the payment service and the machine engine(s) of the Vending Machine. The optional Components Object of BaseComponentsType defined in 7.4 can provide information about subcomponents of the UI. The UI generates Events of VendingBaseAuditEventType to provide audit data.

The UI receives the configuration of the Vending Machine by accessing the Machine Engine capabilities specific to a machine engine from the machine engine(s) of the Vending Machine by accessing the Capabilities Object of MachineEngineCapabilitiesType defined in 7.5. This includes the available selections and possible Options per selection. The availability of the selections is provided by the Status Object of MachineEngineStatusType defined in 7.7. The Delivery Object of MachineEngineDeliveryType defined in 7.6 expose the status of a delivery.

The UI receives price information for the selections as well as payment options provided by the payment service of the Vending Machine by accessing the PriceInformation Object of PriceInformationType defined in 7.11. A deliver request is triggered on the Delivery Object of PaymentServiceDeliveryType defined in 7.9.