Suppliers beat Ethernet’s path to hazardous areas

May 31, 2023
Ethernet-APL mini-series—Day 6—Phoenix Contact, Rockwell Automation, Softing and Yokogawa

While much of the inspiration for Ethernet-APL comes from user and standards bodies, most of the innovations and tools for making it happen comes from their supplier partners. Here’s their take on how it’s unfolding:

Phoenix Contact

Just like all the networking members of the Ethernet-APL organization, Phoenix Contact has worked since 2017 on developing a two-wire, single-pair Ethernet (SPE) platform that could serve in intrinsically safe (IS) applications. It helped produce an early Ethernet-APL exhibit at the NAMUR conference in November 2019, and recently exhibited a prototype, six-port Ethernet-APL switch that could be added to other field devices. It plans to release its first Ethernet-APL field switch in mid-2023. 

“We saw the need for Ethernet-APL just like everyone else, so we enabled connectivity on testbeds with some of North America’s largest consumer packaged goods and food and beverage enterprises to help developers and potential users explore and develop it further,” says Arnold Offner, strategic market manager for support, process automation and networking at Phoenix Contact. “We developed the six-port switch, so field device manufacturers wouldn’t have to develop their own switch. This would free them to focus on developing their Ethernet-APL products. Our 24-port APL field switch will allow users to get data from devices in Zone 1 hazardous areas, put it on the network, and send it to wherever it’s needed.”

Guadalupe Chalas, senior product specialist in Phoenix Contact’s device connector division, reports that SPE was available for a while as an in-vehicle communications network and possible replacement for the Control Area Network (CAN) protocol mostly used in automotive vehicles. “However, SPE also evolved to become the foundation for Ethernet-APL, which is the first proven-in-use version of SPE,” says Chalas 

However, as with any networking technology, users must still decide what production data and field instruments they need—and where to locate them—before they can decide what network to use. Ethernet-APL is just another option in this larger context. “Ethernet-APL is a different paradigm because it gives users access to more varied data and new routes to different places that can improve reliability, maintenance and asset management,” says Jason Norris, group leader of process automation at Phoenix Contact. “In addition, Ethernet-APL doesn’t need to go through the I/O, PLC and DCS infrastructure, so users can access more data that didn’t used to be available. This is especially true if they use publish-subscribe communications like those available from OPC UA and MQTT. The beauty of Ethernet-APL is that it’s protocol agnostic.”

For instance, Offner reports that Phoenix Contact just partnered with Jumo to exhibit an environmental sensor and air-monitoring solution at Hannover Messe in April. Their project uses two-wire SPE networking to relay data to Jumo’s cloud-computing service and Phoenix Contact’s Proficloud service. Its environmental sensor also benefits from the 1,000-meter distance possible with SPE.

“Ethernet-APL also allow two different topologies. The first is a compact design of 200 meters, which can go from a field instrument to our switch in Zone 2,” explains Norris. “The second topology is more long-range, up to 1,000 meters, and can go from the switch zone further up the network trunk to a safe-area controller or other devices.

“Due to these added connections, cybersecurity is also crucial, and the Ethernet-APL organization is beginning to work on it. However, because all of this is managed switch technology, users can maintain security by assigning ports on their switches to only accept communications and data from other specific ports.”

Rockwell Automation

“Ethernet-APL represents enhancements to long-distance, single-pair Ethernet (SPE) for use in hazardous area (ATEX) applications. But even if they aren’t in ATEX Zones 0, 1 or 2 areas, many instruments in oil and gas and pharmaceuticals applications are a long way from their control equipment, so SPE may be a better way to connect them. It’s a simple way to go up to 1,000 meters, and connect remote devices with one two-wire cable for 10 Mbps of data and, in some cases, power,” says Paul Brooks, technical business development manager for Rockwell Automation’s strategic development organization. "We're focusing on allowing this ecosystem to evolve, bringing together partners that can develop SPE and Ethernet-APL instruments with common software interfaces, and supporting specifications to allow Ethernet-APL conformance testing."

Brooks reports that both of these enable two primary network pathways: controller-to-device and device-to-software. “Ethernet-APL and SPE using EtherNet/IP is more easily configurable, and makes more data available to more process variables,” explains Brooks. “From the device back to the controller, these variables can include temperatures that affect the calculation of liquid flows, or raw and corrected gas flows – far more than a traditional 4-20mA single and far faster than HART.

“What’s really interesting is this data also lets us write better control algorithms, which makes our second pathway device-to-software. For example, we can use Ethernet-APL to retrieve extended diagnostics from instruments, retrieve human and machine-readable information, and get all the measurements from devices. Next, we can build a webpage with all this asset data in a human-usable format, or send it to a cloud-computing service for further analysis and long-term storage. This also lets users understand what their devices are doing with expert help from the people who made them, so it also enhances the relationship between users and suppliers.”

To gain these advantages by adopting SPE and Ethernet-APL, Brooks states it can help if users think of software as just another module that’s as simple to plug in as an automation device, and performs a function such as visualizing, manipulating or doing something else useful with their data. He adds that Rockwell Automation enables this capability by providing an edge gateway that brings any process data the user wants to make public into the appropriate software environment. 

“Users can build faceplates with our FactoryTalk View visualization software, and use it to send data from EtherNet/IP devices to our FactoryTalk Production Centre MES software,” says Brooks. “If data is coming from third-party devices, we can use OPC UA to make it available to our software. These networks including Ethernet-APL can maintain cybersecurity the same way that EtherNet/IP does—by implementing its CIP Security functions in their devices for all explicit messaging protected by transport layer security (TLS).”

In the future, once Ethernet-APL gets established, Brooks advises users to challenge Rockwell Automation and other suppliers to push its speed up to 100 Mbps and eventually to the gigabit level, as well as wring more rich data from its devices and processes. “There’s also more work we can do to extend regular Ethernet in non-hazardous areas, but it’s taking Ethernet-APL’s value proposition and momentum to drive those efforts. Ironically, many of Ethernet-APL’s new features and capabilities are needed in those non-hazardous settings.”


Thomas Rummel, managing director at Softing Industrial Automation GmbH, reports that Ethernet-APL’s benefits are so broad that users need to determine why they need it and how it can help each of them.

"Are you trying to communicate with the field, maybe to an area that had no network gateways or barriers before? Or do you need Ethernet-APL's 10 Mbps speed for increased bandwidth or added functions?" asks Rummel. "However, what's more important than bandwidth is consistent protocols. This is because a controller that already supports other Ethernet protocols doesn't need to change on that side to use Ethernet-APL. This also means some control functions can go further. Users may be able to do device commissioning in their controller's engineering tool, instead needing a gateway to reach their remote I/O, and converting regular Ethernet to something else."

Simpler networking thanks to Ethernet-APL subsequently allows easier maintenance, and makes more values and data available via digital protocols for improved process optimization. Ethernet-APL also has the same cybersecurity capabilities as regular Ethernet, so with a couple of adjustments, it can employ the same network segmentation, firewalls, safe zones and encryption.

"The right network infrastructure means more information, more timely asset monitoring, and better decisions and management," says Rummel. "What's important now is many suppliers are releasing Ethernet-APL controllers and other devices this year. What's nice for the process industries is Ethernet-APL switches are still standard, Layer 2 switches, so they can connect to anything on a controller that's running standard Ethernet. In the future, I think costs will come down even more, and we'll see even cheaper single-pair Ethernet switches and other products."

Rummel adds that Softing has developed two related devices, including an Ethernet-APL field switch that’s scheduled for release by the end of 2023, and an Ethernet-APL communication board that can integrate into other devices to talk to other Ethernet-APL components, and is scheduled to launch this summer.


Along with the Ethernet-APL organization's other suppliers, Yokogawa has participated in its development since the beginning.

"Everyone is looking for faster data and the ability to reach more varied types of information. I think we began talking about an intrinsically safe (IS) Ethernet in 2011," says Nicholas Meyer, manager of Yokogawa's industry and product marketing group. "At the time, Profibus and Foundation Fieldbus were the fastest IS communications, traditional Ethernet was only suitable for Zone 2. Due to the risk of ignition, Ethernet originally couldn't go to the edge and device level, especially not in refining, chemicals or other potentially hazardous settings.”

Fortunately, Ethernet-APL networks are built using Type A cable, which is often used for traditional field wiring, and employs a hub-and-spoke topology with individual spurs radiating out from an APL field switch. This is similar to the twisted-shielded-pair cabling used by Foundation Fieldbus and Profibus PA.

“With Type A in a hub-and-spoke, one pair goes into the field, and each devices comes back via its own spur,” explains Meyer. “This is also different than 4-20 mA, which is point-to-point and require each device to go back to the center on its own. Ethernet-APL is better because only one set of wires is needed to get back to the central host.”

Simpler networking and the fact that Ethernet-APL can still talk to HART, Foundation Fieldbus and Profibus protocols opens several interesting possibilities, according to Meyer, who reports that Yokogawa plans to release an Ethernet-APL-capable version of its RotaMass TI Coriolis flowmeter in the near future.

“Ethernet-APL is faster and has more efficient wiring practices, but because it’s only a change to the physical layer and uses existing protocols, users also benefit because they don’t have to learn a totally new communication technology,” says Meyer. “And, because Ethernet-APL runs at 10 Mbps, which is over 300 times faster than existing IS devices, users can get whole new dimensions of data because they don’t have to leave it stranded in the field due to difficult communications. In the past, users had to operate and maintain more complex field devices to deliver their data, but now the pipeline is much bigger, and field devices can provide much higher-fidelity information about pumps and other equipment. Users no longer have to program complex algorithms in their field devices, they can just send lots of data to their edge computers or to the cloud, where artificial intelligence (AI) programs and analytics can enable next-level operations and plant optimization.”

For instance, when a pump is experiencing cavitation, traditional networking’s limited capacity could only convey enough data to indicate if the condition was happening or not. With Ethernet-APL’s greater capacity, more raw information can get through including measurements and other data about the process or field device. For example, HART only delivers data once every three seconds, and Foundation Fieldbus and Profibus only deliver it once per, but Ethernet-APL can provide data about 60-100 times per second, which is faster than most sensors can generate it.

“This speed and bandwidth let users send production data without being concerned about their power budget, model normal versus abnormal operations, and enable AI to determine whether a certain amount of cavitation or another issue is acceptable or needs to be dealt with based on efficiency, quality, cost and other impacts,” adds Meyer. "Ethernet-APL is going to be the standard for networking new plants in the future.”    

About the Author

Jim Montague | Executive Editor

Jim Montague is executive editor of Control. 

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