One for all?
How does a uniform fieldbus standard benefit users?
Digitization is intensifying competition in every industry, individualizing products and shortening product life cycles – only when it comes to the fieldbus is it supposed to be providing a uniform and eternal solution. The magic word here is OPC UA, but is it really going to work? CHEManager discussed this topic with Karsten Schneider, Chairman of Profibus & Profinet International (PI). Volker Oestreich conducted the interview.
CHEManager: Can OPC UA and Ethernet TSN be extended to the device and field level? If so, what role do classic fieldbus and Ethernet systems play here?
Karsten Schneider: OPC UA is seen by many as an option for replacing the plethora of different available fieldbus solutions with just a single one. This desire on the part of users is understandable, as machine manufacturers today – to name one example – have to use different fieldbus solutions for their machines depending on the industry, region and area of application. From my perspective, this initiative will only be successful if a solution based on OPC UA provides real added value in addition to the features of today’s fieldbuses. Without this added value, it will be difficult to convince every user to switch over from their current solution to the new technology. It would also come along with an added expenditure which would have to be worth it. Besides this additional expenditure, they would of course also have to take into account the time required to develop such a solution. Today, our Profinet features many functions which aren’t even available in OPC UA. In addition to classic profiles like I/O, Safety and Motion, you have aspects like system redundancy, easy device swapping without additional engineering, energy efficiency and lots more. That’s why I think the fieldbuses of today will continue to play an important role for a long time to come. Even Profibus, which was developed more than 30 years ago, still plays an important role – even though significantly more new Profinet nodes have come onto the market in the meantime, of course. As PI (Profibus & Profinet International), we see it as an obligation to support our customers for the long term.
Is PI still a driving force when it comes to “Ethernet in the field,” or is it a force that’s being driven?
K. Schneider: PI is, and will remain, the driving force here. Absolutely. Our organization has been the source of many innovations over the decades, and we have no intention of stopping. Some recent examples include FDI (field device integration), APL (advanced physical layer) and the adaptation to TSN (time-sensitive networking), but the working model has changed somewhat. While we used to consider purely communication-related aspects in the past, applications play a primary role today. Simply transferring data from A to B is no longer enough. The data has to be converted into usable information. We’ve addressed this topic in the Industry 4.0 working group and are developing the technologies required for this. We’re currently defining the semantic description for our information model together with eCl@ss, for example, and we’re also the first fieldbus organization to be cooperating closely with eCl@ss. We are also actively working together with the OPC Foundation to define new standards. We’ve already defined requirements and technical solutions for OPC UA which enable OPC UA to be used for additional applications in the field. We have also advanced the topic of safety over OPC UA from PI and are developing it in a joint working group with the OPC Foundation.
The supply of auxiliary energy to field devices over the fieldbus is a necessary requirement for the process industry. How are things looking with APL, the advanced physical layer for Ethernet?
K. Schneider: Ever since I founded the APL project under the umbrella of PI and in cooperation with the ODVA and the FieldComm Group last year, good progress has been made here. The technical working group has gotten started with this task, and I’m confident that we’ll create a great solution within the planned time frame of three years. At the same time, we’ve also initiated standardization. We’ll be providing relevant information to users and manufacturers at trade fairs like the upcoming Hanover Fair, for example. What makes APL special is that it’s a purely physical layer. As soon as development of the technology is complete, APL will seamlessly integrate into Profinet.
How will current and future communication systems of the field devices fit into NOA, the NAMUR Open Architecture, and how will they handle the “communication diode” function requested for security reasons?
K. Schneider: We see NOA as a very exciting topic which corresponds ideally with our strategy for Profinet. We already began to view Profinet and OPC UA as a common solution for automation tasks early on. Profinet is primarily responsible for the cyclical exchange of data between the PLC/DCS and the field devices here, and OPC UA handles both vertical and machine-to-machine communication. Profinet`s openness enables both to be operated on the same network and in the same devices. This means that NOA can be implemented very well. Thanks to our activities in modeling and the semantic description of data, we are able to offer real added value for NOA. The communication diode issue can also be solved with our technologies. The Profinet and OPC UA stacks are easy to keep separate within a device, thus preventing any undesirable effects from arising. On the network, TSN will handle this task. By utilizing separate streams, I can reserve bandwidth for individual tasks, thereby preventing any effects of access from the M+O (monitoring and optimization) sphere in the automation network. This makes it easy to see how future-oriented Profinet´s architecture is.
What role will the new 5G mobile communication standard play, and how will it fit into the fieldbus and Ethernet communication concepts?
K. Schneider: 5G will be a very interesting option for many areas of application. With mobile applications in particular, like AGVs (automated guided vehicles) and moving machines and systems (e.g. cranes etc.), 5G will definitely be a relevant solution alongside WiFi, for example, and local sensor networks like Wireless HART. Remote stations, such as pumps, and remote access points can also be implemented with it. At PI, we’ll be working on the necessary steps in the Industry 4.0 working group. The 5G standard itself is from the telecommunications field, so all we have to do is define the interface to the network. Similar to TSN, the necessary mechanisms will thus be incorporated into our Profinet standard. The implementation of these steps is beginning now.
Trends in technology regarding Industry 4.0 were also the focal point at the PI conference on March 19 and 20, 2019 in Frankfurt, Germany. What references to automation in the process industry were of particular importance at the conference?
K. Schneider: The PI conference was an excellent opportunity to learn all about PI’s full range of work. There were presentations geared more towards managers and product managers and others addressing technicians and developers. The latter dove deeply into the bits and bytes of our technology, whereas the former included an outlook for the future – the big picture. Every area of interest was covered, from IO-Link to Profibus to Profinet and from APL to TSN to 5G. From the process industry standpoint, APL and the new PA profile are of course the most interesting topics. Presentations on semantics and information models are valuable to anyone who would like to implement NOA. And how could we forget about the character of the network – we don’t just define technical communication networks, we also form a massive human network. This has given us ample opportunity for in-depth interaction with manufacturers and users of our technology!