A sensor solution with Industry 4.0 capabilities

A prerequisite for high data transparency is an intelligent and standardised data interface. However, this alone is not enough to be able to realise Industry 4.0 systems. The RAMI 4.0 reference architecture model of the Industry 4.0 platform offers a representation for industry.

RAMI depicts the properties of Industry 4.0 components in three dimensions. Firstly, the product life cycle is described – here, product data such as production data, data sheets, configuration data, etc., is collected. In the next dimension, a hierarchy is recorded, while the third dimension represents the IT representation. 

Industry 4.0 components need to be describable using the RAMI 4.0 model which means that a true Industry 4.0 sensor must be able to communicate across all IT levels. Currently, this is not possible for a sensor with a classic fieldbus interface, which communicates exclusively with the control, but does not pass data to the upper IT levels.

Unlike classic fieldbus interfaces, an interface that is expanded with the OPC UA communication model is able to transport data to higher IT levels of the RAMI model. 

OPC UA includes a security implementation that consists of authentication, authorisation, encryption and data integrity with signatures. Unlike communication methods typically used in industrial environments, it allows for secure communication. From the field level of the automation pyramid, OPC UA can communicate via two different mechanisms – either via client/server communication or via a publisher process. With client/server communication, an OPC UA server is integrated in the data source – a sensor that can deliver data to a data recipient. With the publisher process, an OPC UA publisher is integrated in the data source.  This can then make its data available to various data recipients. If there is more than one data source in the system, the data recipient can decide which data it would like to receive from which publisher. This means that the recipient does not always need to accept the data from all publishers. Using this process, communication from data sources to data recipients is possible. A data cloud can also retrieve data directly from the data source. Communication in the opposite direction – from the cloud to the sensor – will also be possible in the future. 

Industry 4.0 requires compatible communication and OPC UA is able to virtually ‘tunnel through’ the layers of the automation pyramid and transport data to the higher levels of the RAMI model. This makes standardised communication of sensors and actuators from various manufacturers directly with a cloud-based ERP system possible. Thanks to the secure communication, even the exchange of data between different systems via public channels is conceivable. 

However, the provision of data from components via OPC UA communication alone is not enough for an Industry 4.0 application. Additional mechanisms are required for data acquisition from the cloud. To realise telemetry data without additional components, such as an Industry 4.0 gateway, Leuze electronic and Microsoft have, therefore, collaborated to find a solution. The result of this collaboration was demonstrated at the SPS/IPC/Drive event in November 2016. Sensor data from the Leuze electronic BLC 348i bar code reader can be transmitted via the OPC UA Publish/Subscriber Communication Model (PSCM) to Microsoft’s Azure IoT Hub. This data is recorded there by the IoT hub and made available to the Azure Cloud Services for analysis and visualisation. 

The collaboration demonstrates how an embedded device can be controlled from the Azure Cloud. Using the bar code reader as an example, Leuze electronic has shown how a device can be addressed from the cloud on the lowest RAMI level without the need for another gateway. The reading gate of a bar code reader can be controlled from anywhere in the world by any mobile device via the Azure Cloud. 

The sensor data recorded by the IoT hub can also be be analysed by analysis tools of the cloud according to predetermined criteria and this can trigger events in the Industry 4.0 total system.