Ethernet-APL: "Making the transition is our top priority"

André Fritsch: It's a mixed bag. While we are definitely seeing a significant amount of interest in it, many companies are still quite resistant to the use of Ethernet in the field, or are at least sceptical. This comes as no surprise. The attitude to adopting innovations is and always has been fairly conservative in the process industry: "Let's wait until someone else has tried it." Whether that's the right strategy in an ever faster-moving, increasingly internationalised world is debatable. And that applies not only to the companies that operate industrial systems, but also to manufacturers and engineering firms whose policy is to wait and see – they're going to quickly find that they've been left behind.

There are substantial advantages to opting for Ethernet in the field as opposed to other solutions such as conventional 4 to 20 mA technology or FF H1 and PROFIBUS PA fieldbuses. I'd go so far as to say that without Ethernet-APL, the notion of seamless digital connectivity for processing plants is a non-starter. Needless to say, there are still a number of matters that need to be clarified when it comes to Ethernet-APL: What should your security concept look like? What should you do about safety applications? Who will supply you with the kind of devices you need? How do you train your staff? Etc. These questions are currently being addressed and it won't be too long before we have the answers. So I'd recommend jumping on the digital express train – as nice as the steam train may be, it's reached the end of the line.

André Fritsch: It depends on whether we're dealing with a new installation or upgrading an existing one. And obviously, if you're upgrading an existing installation, your background knowledge is important, and whether you have any experience with digital solutions like fieldbuses and remote I/O. The infrastructure that is already in place and the distances between devices are also relevant to the planning process. If you were planning a pharmaceutical facility that occupied only a limited amount of space and you had an Ethernet backbone to which everything was linked, you could opt for a simple star-type topology, as is commonly used for Ethernet networks. But if you wanted to have Ethernet-APL throughout a tank farm, it would make more sense to use a fibre-optic backbone or a trunk-and-spur-type topology. This would allow you to cover distances of 1000 m or more. When it comes to explosion protection, Ethernet-APL makes life relatively easy – solutions are even available for field devices used in Zone 0 areas, and field switches can be installed in Zones 2 and 1.

If you are upgrading an existing installation, there is also the matter of whether the cables that are currently in place can still be used. Ethernet-APL has been designed specifically for use with type A fieldbus cables, as used for FF H1 and PROFIBUS PA. This means that, on paper, this cable type should enable you to use Ethernet-APL over the full 1000 m. But experience has shown that, in practice, these cables often fall short of this specification or are simply too old. Generally speaking, it is still possible to use 4 to 20 mA cables, albeit with some limitations on the maximum distances they can cover. Needless to say, in the interests of maintaining maximum system availability, the cables should be carefully checked – at the end of the day, we're talking about 10 Mbit/s, as opposed to the 31.25 kbit/s fieldbus speed.

André Fritsch: There is still work to be done on various fronts. Field device manufacturers need to make sure that all the relevant devices are still available with Ethernet-APL. That's obviously a big ask, but it's urgently needed. Without the devices, there can be no Ethernet-APL. In terms of the infrastructure components, the field switches, things are looking pretty good right now. There are a few manufacturers who either already have devices available or are just about to launch them. With regard to control systems, the main thing is that they support users' preferred protocols – NAMUR recommendation NE168 lists PROFINET and EtherNet/IP as minimum requirements. We're not quite where we need to be with PROFINET, particularly since PROFINET was designed specifically for transmission speeds of 100 Mbit/s – however, the necessary adaptions for Ethernet-APL and its transmission speed of 10 Mbit/s are currently in the works.

And finally, we come to the end users, who, along with their planning firms, must actively address the subject of Ethernet. In concrete terms, this includes measures such as training employees. In the past, this has often been "forgotten" when it comes to fieldbuses – "It'll be fine, we'll figure it out," was the excuse; it was not fine, as it turned out. One advantage of Ethernet-APL, though, is that most companies already have the basic expertise in house: IT departments have already been working with Ethernet networks for years. What remains then is to "merely" establish the corresponding link to the OT and the process automation systems – this does, in reality, require a certain amount of work.

It is important to note here that we're not just talking about running an Ethernet cable into a hazardous area – using Ethernet in these kinds of industrial environments will only be successful if the processes behind it are "digital" and if "NOA", "life cycle management" and "MTP" are more than just buzzwords.

André Fritsch: Cyber security is an important issue, whether or not we're talking about Ethernet-APL. And an effective solution requires more than just Ethernet-APL. The expansion of Ethernet use into the field means that field devices are now easier to access and can more easily be tampered with. But that by itself is not grounds to shy away from using Ethernet in the field. With that line of reasoning, we'd still be using typewriters to tap out our company correspondence. A functional security concept has two basic components: The security management system and the security culture. These form the basis for technical and organisational measures. Having Ethernet-APL can be an advantage here. For example, security patches can be automatically rolled out to all devices via the network. And monitoring processes that are running in the background automatically flag up any security problems. It goes without saying that we have incorporated corresponding password levels with different user roles into our field switches, and configuration and parameterisation can be implemented exclusively via the master engineering system or control system and not on the field switch itself. So that means a read-only connection or NOA diode. This must all be integrated into security concepts such as the "defense in depth" approach or the "zero trust" model.