Process Automation Unleashing a New Level of Industrial Communication with Ethernet-APL

From Andreas Hennecke*

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The future of process plant communication will be triggered by one key technology: Ethernet-APL. This end-to-end Ethernet solution will enable the free flow of information to and from the field and finally unleash the full potential of the visions behind Industry 4.0.

Ethernet-APL fit for the field, with cable lengths of up to 200 m between switch and instrument.
Ethernet-APL fit for the field, with cable lengths of up to 200 m between switch and instrument.
(Source: Pepper+Fuchs)

Presently, digital process control and office communication are two strictly separated worlds with only limited interaction. The digital future, however, calls for a seamless and secure flow of data without technical, functional or geographical limitations. End-to-end Ethernet on premises is the key requirement for such a future, and Ethernet-APL is the enabling technology to make it all happen.

Ethernet-APL is a giant step into the future. We are convinced that in the future all field devices will work with IP-based communication. They will support applications that don't even exist today.

Lutz Liebers

“Ethernet-APL is a giant step into the future. We are convinced that in the future all field devices will work with IP-based communication. They will support applications that don't even exist today,” says Lutz Liebers, President of the Process Automation Division at Germany-based Pepperl+Fuchs. The company is an early advocate of the Ethernet-based Advanced Physical Layer (APL) and has taken a leading role in the development of this technology.


With the introduction of Ethernet-APL an advanced physical layer for enhanced communication was established and a long-time vision of both automation system vendors and plant operators has come true. This technological milestone will finally connect process automation with the omnipresent digital world dominated by Ethernet communication. It will not only put an end to existing system limitations. It will also enable a totally new level of control, efficiency and flexibility throughout the complete life cycle of a process plant.

Already by 2009, experts at Pepperl+Fuchs developed the first ideas and concepts for a new communication standard matching the requirements of the process industry. Since then, a dedicated team has persistently worked on the development of APL as a new physical layer for existing infrastructures and a communication path for comprehensive Ethernet communication in process plants. They not only cooperated closely with industry standardization bodies and user groups, such as the Field Comm Group, ODVA, the OPC Foundation and Profibus/Profinet International. They also triggered a strong drive for global acceptance of Ethernet-APL as a future, standardized and open technology for the process industry, and inspired the collaboration of twelve major equipment suppliers.

About Open Communication
Process Q&A with Michael Kessler, Executive Vice President Components and Technology

? Michael, you are convinced that all devices will be IP-based. However, the process industry is still considered a very conservative clientele. What is the period of time that we are talking about until Ethernet-APL has largely replaced today’s communication technologies?

Michael Kessler: In our dialogs, early adopters evaluate Ethernet-APL for large-scale plants that will go live in two to three years. However, a plant life cycle of 20, 30 or more years gives an idea of what it will take to arrive at large-scale adoption. Ethernet infrastructure is well established in offices, discrete manufacturing, and even our homes. I firmly believe that we will see fast adoption of Ethernet-APL, as it brings this potential to the field of process plants.

? Large corporations often find it easier to implement new technology compared to small and medium-sized enterprizes. What are your expectations for Ethernet-APL?

Michael Kessler: It is true that large corporations have the resources, specialists and methods to implement new technologies. The advanced physical layer makes standard Ethernet technologies available in the field. This meets with a future workforce with skills in Ethernet communications. Therefore I expect broad adoption across all sizes of companies and for all sizes of applications. Ethernet-APL fulfills users’ expectations of “easy access to anything” without the complexity associated with legacy communication technologies.

? Standardization brings tremendous benefits for the end user, but what are the benefits for the equipment supplier like Pepperl+Fuchs?

Michael Kessler: Good question. Standardization creates a larger market and more business opportunities for everyone, where competition at the physical layer creates barriers that limit adoption. This is one of our core beliefs and the main reason that we invested heavily into the standardization and development of the technology behind Ethernet-APL.

? At what point can you still play out your USPs in a standardized world?

Michael Kessler: Implementing basic technologies does not provide any differentiation. Unique value comes from features beyond the basic technology in our products. Some examples are: FieldConnex APL Field Switches automatically adapt to Profibus PA and any Ethernet-based instruments. Their low-power circuit design is ideal for energy-
efficient operation in hazardous areas and at extreme temperatures. And of course they include physical layer diagnostics, which are crucial to maintain highly reliable communications.

Seamless Communication Infrastructure

One major advantage of Ethernet-APL is the fully transparent communication of all device data of a plant without the known restrictions imposed by gateways. This includes direct access to the instrumentation independent of and in parallel to the control system. This will greatly boost the seamless interaction of all major driving factors behind the digital transformation: Internet Everywhere, industrial internet of things (IIoT), big data and cloud computing. It will also help to eliminate many manual processes and enable a high level of automation along the complete life cycle of a plant. System design will be accelerated and simplified dramatically, devices will be detected and calibrated automatically and predictive maintenance will become the norm.

As an example, Ethernet-APL will enable the automation system to automatically recognize any field device during implementation and after replacement. Device data can be stored centrally and used for automatic configuration without the need for any on-site manual interference. “Ethernet-APL is not simply another fieldbus. It is a physical layer for already existing infrastructures and ecosystems. It enables any kind of communication via Ethernet. A field device could even send an e-mail,” explains Michael Kessler, Executive Vice President Components Technology at Pepperl+Fuchs. Since its official acceptance as an international standard, Ethernet-APL is part of the complete basket of different Ethernet standards and fully compatible with the worldwide established Ethernet communication.

Ethernet on Two Wires for Process Plants

It is important to clearly differentiate between Single Pair Ethernet (SPE) and Ethernet-APL. SPE describes a family of communication standards. Protocol-independent Ethernet-APL utilizes one of these standards and goes way beyond, by defining all electrical characteristics that are required for a single infrastructure. The utilization of existing wiring protects investments. Power supply and data transmission via one and the same cable greatly simplifies system planning, installation and implementation. The user organizations involved today adopt common, standardized test methods to guarantee conformity. Robust connection technologies, lightning protection and high EMC standards contribute to reliable operation. Intrinsically safe hazardous area protection is not only an integral part of the standard. Installation is also greatly simplified, while strict power limitations are a thing of the past. Landing wires on terminals is the most common connection technology supported by Ethernet-APL.

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Ethernet-APL not only enables concepts such as the Namur Open Architecture (NOA). It is also a communication standard that is approved by all leading industry standardization bodies.

With Ethernet-APL, Pepperl+Fuchs focused on an open standard that can be freely adopted by all device manufacturers and has already generated wide recognition within the process industry. A first fully functional demonstrator was presented to the process automation world in 2015. A total of twelve manufacturers and leading user organizations have been collaboratively working on the standardization within IEC. They are committed to Ethernet-APL as the enabling technology for a new level of plant automation in the digital age.

Digitalization for All Process Plants

Lutz Liebers comments on the open strategy of Pepperl+Fuchs: “As market leader we are proud of our efforts to establish Ethernet-APL as a core technology. Ethernet in the field will fulfill the high expectations of our customers. We invite additional market participants to become part of this technological advancement by developing their own devices.”

A comprehensive engineering guide written by experts from multiple industry partners provides especially first-time users with the complete know-how and experience gathered by both user organizations and device vendors. It contains a valuable set of rules, as well as best-practice guidelines to help plant operators to avoid the typical pitfalls often encountered when planning digital communications infrastructure for the field.

Ethernet-APL is now ready for real-life applications and has the potential to finally replace 4...20 mA technology with a contemporary digital infrastructure. All related standards will be published at the Achema Pulse 2021 trade fair. Chip manufacturers are ready for delivery. One of the first products available in the market is the Field Connex APL Field Switch. It not only works seamlessly with any APL field devices on the market. It even supports the simultaneous operation of standard Profibus PA field devices and future APL-enabled Profinet devices.

A strong sense of optimism can be felt throughout the industry. Not only key users such as BASF in Germany have embraced the new technology. Plant builders and engineering companies show interest and are already evaluating the use of Ethernet-APL for plants currently in the planning stage.

Ethernet-APL allows for multiple migration paths from an existing process control systems to a fully digital solution. They all have in common the fact that any existing 2-wire cables can remain in place and will continue to serve their purpose. If the plant already uses digital communication at field level via Profibus PA, upgrading it for Ethernet-APL communication is especially easy. In this case, all that needs to be done is to exchange existing field barriers and segment protectors with APL Field Switches. The APL Field Switch will automatically adapt to the system, detect any existing fieldbus devices and establish seamless communication with them.

The life cycle of a new process plant usually does not begin with the purchase of hardware, but with comprehensive planning.

Lutz Liebers

Liebers adds: “We are prepared to work closely with users who want to create the prerequisites for Ethernet-APL already in their planning phase.”

Now is definitely the time to take the vital step and adopt Ethernet-APL as the technology to pave the way for improved plant efficiency and unlimited transparency. A wealth of innovative digital solutions is waiting to be utilized.

* * The author is Product Marketing Manager, Pepperl+Fuchs SE, Mannheim/Germany