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Blog: Single-pair Ethernet – System adoptions in different scenarios

Part 3: System adoptions in process automation

While the factory automation networks largely base on Ethernet standards today, the adoption of Ethernet in the process automation field is still in progress. To address and enable business models for Industrie 4.0 and Industrial Internet of Things, the Namur released an open architecture (NOA) defining a communication concept across all layers to the cloud. Namur also released a paper to determine future networks in process automation to be IP networks with Ethernet. The FieldComm Group together with PI and ODVA formed a group that has driven the progress in IEEE to a large extend and determined their system requirements for a fast adoption into the field.

The picture shows the different zones in a process plant to address different levels of intrinsic safety and loop-powered or separate powered devices in hazardous areas like in Zone 0. The network itself uses the well-known spur and trunk topology that includes the ability to power up to 50 devices with up to 500mA each. Furthermore, existing cables and installations can be reused to reduce the effort of system design and integration time. Hence, the focus of the process industry is to replace the existing fieldbus installations with APL continuously.

System adoptions in factory automation

In opposite to process industries, Industrial Ethernet is the dominant network in factory automation industries. However, this also limits the benefit arguments of SPE, that are valid in process automation industries, to that of smaller footprint, less cable weight, enhanced cable length, increased robustness easier installation and maintenance through one tool environment.

The challenge is now to bring these advantages into existing IP based networks that already enable many of the current data driven business models. The challenges are manifold. Some of the industrial Ethernet standards have no 10Mbit transmission speed in their specs or just started to include.

Several sensor manufacturers - being main drivers in APL for process automation - were already actively aligning their needs within the IO-Link standard starting back in 2007. IO-Link supports parametrization, diagnosis and full integration into “Industrie 4.0” eco-systems. However, transporting IO-Link Frames over 1000m of SPE would transfer the former point-2-point sensor network into a kind of fieldbus. A positioning discussion is required to resolve and avoid confusion. Despite these technical matters, a key question for factory automation is the use cases that would benefit from SPE. Various groups in PI, ODVA and IO-Link currently discuss and evaluate these use cases and potential integration scenarios into the field. The IO-Link Consortium has released a whitepaper with several examples of deployment scenarios (IO-Link Consortium, 2020) picking up some sample installations in the brownfield:

SPE installation in IO-Link eco-system (source: IO-Link Consortium 2020)

The example allows integrating IP67 SPE master into an existing installation of IO Link and binary sensors and devices. The proposal in the whitepaper takes SPE mainly as a transport medium for IO-Link Frames.

IO-Link data integration into Ethernet hardware and datagrams (source: IO-Link Consortium 2020)

A software based Ethernet to IO-Link adapter allows to maintain the data format and use the range extension and other SPE benefits by maintaining the opportunity to keep the existing infrastructure and installations alive.

Hilscher participates in several working groups of PI to contribute to the discussions on SPE for PROFINET. We also contribute to the IO-Link working group evaluating the benefits and challenges for a complementary integration of both standards into the field. In IEEE we share the discussions on remaining open topics in the 802.3cg standard and we participate in discussions of the ODVA on SPE topics. Our goal is to help building a migration path to have low-effort integration of SPE into existing systems and to support this with our competence in communication and our products.


IO-Link Consortium (2020), Gringauz, Moritz, Lindenthal, Witte, “Concept study Extension of IO-Link for Single Pair Ethernet transmission” (Whitepaper)”

Related Links

Learn more about SPE in our whitepaper from Niels Trapp! Click on the Link for download.

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Part 4 of our blog series about Single-Pair-Ethernet: A lot of work is still ahead of the industry to get open questions resolved in terms of system adoptions, standard integration and leveraging benefits in relevant use cases. How do the future prospects of SPE look like?

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