Manufacturers of measuring devices have always had to adapt their components to the variety of protocols and interfaces. The effort involved is considerable and increases from year to year. After all, it's not just about implementing a specific protocol, but also about testing, certification and documentation - and this varies greatly around the world. For example, operators in some countries want Modbus RTU, in others they rely on Fieldbus Foundation and in still others on Profibus - not forgetting the HART protocol, which is superimposed on the 4 to 20 mA signal.

For medium-sized companies like Vega, this is always a balancing act. On the one hand, customers' wishes need to be fulfilled, but on the other hand, the cost increases with every interface implemented. "In the course of Industry 4.0, the requests and wishes of users with regard to device-internal interfaces are increasing once again. It is important to offer a long-lasting solution here," explains Ralf Höll, Product Manager for System Components and Communication at Vega. Three examples demonstrate the company's pragmatic approach to Industry 4.0:

Secure data transmission

To obtain data from the process, 'Plicscom' offers a wireless solution with Bluetooth, which can also be used to convert the installed base of sensors.

© Vega

When the Bluetooth interface for the company's measuring devices was introduced two years ago, nobody was thinking of the buzzword Industry 4.0. Rather, the aim was a solution that would make it possible to bring measurement data directly to the user: Because level sensors, for example, are often installed in potentially explosive areas, in containers with toxic or abrasive media or at dizzying heights on silos, it is difficult to read the measured value directly or make a diagnosis. This can be done wirelessly via Bluetooth using a smartphone, tablet or laptop. All that is needed for implementation is to unscrew the cover of the measuring device, attach the 'Plicscom' display and operating module and screw the cover back on - all without updating the sensor software. It was specified in advance that the Bluetooth solution should be backwards compatible and compatible with all continuously measuring Vega sensors, as there are over 1.5 million Vega sensors installed in the field that would benefit from this solution. In addition, access to the sensors had to be protected with individual codes and data transmission had to be encrypted to ensure secure communication.

Over 80 different sensors can now be equipped with Bluetooth. In future, tools for managing access codes are also to be offered. In addition, the Bluetooth solution could be used not only for display and diagnostics or commissioning, but also as a gateway, as it offers a second data channel.

Ethernet for field devices

Interfaces and standardization also occupy the measuring device manufacturer in other respects. Although many users in the process industry find the idea of a powerful Ethernet solution in the field tempting, a comprehensive introduction has so far always failed due to the lack of a viable concept for use in potentially explosive atmospheres. Now the topic is gaining momentum: a corresponding 'physical layer' for Ethernet-based communication in the field of process plants is currently being developed under the name 'APL' (Advanced Physical Layer) as part of a joint project between well-known industrial companies and organizations. Based on the new Ethernet standard currently being specified by the IEEE 802.3cg working group for 10 Mbit/s via the 2-wire cable and for a distance of up to 1000 m, a new standard is currently being developed that can also be used in potentially explosive atmospheres. In addition, the solution is to be tested as part of reference designs and pilot implementations.

Vega is an industrial partner in the APL project and is supporting the development and standardization. Further prototypes containing APL will be presented at Achema. The plan is for the first devices to be on the market in 2022. In future, Vega will be able to equip its continuous measuring sensors with the APL interface. "For us, the world of measuring devices for level and pressure measurement has been digital for many years, be it with a connection to the fieldbus world or via 4 to 20 mA with a HART connection. With APL, there will be another leap forward," Ralf Höll is convinced. Although many measuring devices are currently digital, they are not permanent: a control system can query the status of a field device if it has been designed in accordance with NE 107, but further digital data is not stored continuously. In contrast, Ethernet-based systems can transport a larger volume of data more quickly. And this is precisely what is required for Industry 4.0 applications in order to generate additional benefits for customers.

Forward-looking inventory management

Which medium can be found where and in what quantities? Predictive, supplier-controlled inventory management in the sense of Industry 4.0 can be realized with the 'VMI' solution from Vega.

© Vega

The implementation of predictive inventory management for 'to-the-point production' is already a reality. Vega's 'VMI' (Vendor Managed Inventory) solution - inventory management by suppliers - was also launched before Industry 4.0. The principle has remained the same to this day, but the method of data transmission has changed. Whereas back then data was sent via modem, today it can be transported directly from the sensor to the cloud and processed there by the supplier, who initiates the delivery of a medium, for example. This is not only conceivable for inventory management; the data can also be processed further and used in ERP systems, for example. Typical applications include deliveries to large bakeries with different types of flour, petrol station deliveries with additives such as Adblue, internal product deliveries to chemical parks or the use of mobile silos in the building materials industry. "For the latter application, we had to initiate further developments, such as equipping the 'Plicsmobile' communication unit with robust and long-lasting batteries to enable safe operation on construction sites," explains Höll. "These things may seem minor at first, but they have to work just as reliably as the sensors."

Ultimately, interfaces such as APL or solutions for inventory management open up additional opportunities for customers and companies. With APL, device descriptions, manuals or even videos can be stored directly in the device. Thanks to Bluetooth, service operations will change in the medium term. According to Höll, it is crucial that things are thought through to the end. Every development must bring clear added value for the customer and be easy to use. Standardization and security play a major role in this.

Author:
Sabine Mühlenkamp is a specialist journalist for chemistry and technology in Karlsruhe.