The Pragmatic Engineer's Take on Single Pair Ethernet: Turning Challenges into Opportunities

The technological landscape is in constant flux, and the field of industrial communications is no exception. Single Pair Ethernet (SPE), with its promise of streamlined connectivity, is slowly emerging as a significant player. This technology, which transmits both data and power over a single twisted pair of wires, offers simplified cabling, reduced costs, and enhanced network capabilities from the sensor to the cloud. However, the path from theoretical promise to practical implementation is rarely smooth, and a clear-eyed assessment of the challenges is crucial for successful product development.

While SPE has much to offer, product engineers will face a number of hurdles that need to be overcome. These challenges range from standardization issues to performance limitations and integration complexities. As a product engineering service provider, we are here to offer our expertise to help you navigate these challenges and create innovative and reliable SPE-based products.

One of the most significant hurdles is the evolving standards landscape. While there is a push towards the IEC 63171-6 connector for industrial applications, other connector options exist, and the potential for a fragmented market remains, despite the recent announcement of PROFIBUS and PROFINET International (PI), that it presented yet another uniform mating face for SPE at SPS 2024 and submitted it for international standardization. This means that product developers must be aware of different standards and ensure compatibility of their products. Furthermore, even when a single standard such as the new mating face is preferred, other standards are relevant. For example, the IEEE 802.3 standard is the basis for SPE technology. These standards specify the physical layer characteristics and other important aspects of the technology. Designing products that meet these standards requires considerable expertise.

Another set of challenges revolves around performance limitations. While SPE offers sufficient bandwidth for many applications, it has inherent limits in terms of data rates and transmission distances. For example, the 1000BASE-T1 standard has a maximum reach of 40 meters, while the 10BASE-T1L standard, offering a reach of 1000 meters, is limited to 10 Mbit/s. Furthermore, while Power over Data Line (PoDL) is a significant advantage of SPE, it may not be adequate for devices requiring higher power. This means that product engineers must carefully select the appropriate SPE standard for their products, and might need to provide alternative ways to power high-power devices.

Then, one should also consider the complexity of integrating SPE into existing systems. While SPE simplifies cabling, it can be challenging to connect new SPE devices to existing non-SPE systems. Some companies may have installed legacy systems, and transitioning to SPE will require planning and effort. In some cases it might be more convenient to keep using existing 4-pair Ethernet. Further, there is a need for new tools for field connectorization and managing variations in cabling. All of these issues require expertise in system design and integration, and an understanding of the relevant standards.

Additionally, electromagnetic compatibility (EMC) and electromagnetic interference (EMI) are concerns that must be addressed. SPE is now being used in many environments with demanding requirements. Therefore, product engineers need to ensure their products meet the stringent EMC/EMI requirements of those environments. This often involves careful design and testing, and may require the use of specialized components, such as common mode chokes.

Furthermore, there's the need for robust cybersecurity. Connecting field-level devices directly to an IP-based network increases the attack surface. This means that SPE based products will require robust security measures to protect them from cyber threats. Product engineers must therefore integrate security measures in their product designs to ensure that they are resilient against attack. This becomes even more important in the light of the recent introduction of legislation (see the EU cyber resiliance act) enforcing measures against attacks to protect consumers.

So, how do we turn these challenges into opportunities? By applying a pragmatic and rigorous engineering approach that is firmly rooted in both theory and practical application. That’s where my company's product engineering services can help.

Here's what we offer to ensure the success of your SPE-based products:

• Standards Compliance: We provide expert guidance on the relevant standards, ensuring your product meets all the necessary requirements for performance and interoperability.
• Performance Optimization: We assist with the selection of appropriate SPE standards and help optimize your product design for performance, whether it's high bandwidth or extended reach you require.
• Power Management: We develop solutions that address the power requirements of SPE devices, including PoDL and alternative power methods, when needed.
• System Integration: We help integrate your SPE-based products into existing and new systems, minimizing disruption and maximizing benefits for end users.
• EMC/EMI Testing & Design: We help you design and test your products to ensure they meet the stringent EMC/EMI requirements, helping to minimize interference and ensure reliable operation.
• Cybersecurity Integration: We integrate robust cybersecurity measures into the design of your products, providing protection against the cyber threats in today's connected world.
• Prototyping and Testing: We assist with the development of prototypes and provide comprehensive testing to ensure the performance and reliability of your SPE-based products.
• Supply Chain Expertise: We offer supply chain solutions to optimize sourcing and reduce manufacturing costs [39].

The rise of SPE presents both challenges and opportunities for product engineers. By taking a rational approach and focusing on the practical aspects of product design and development, we can create innovative and reliable SPE-based products that meet the needs of the modern industrial landscape. Let's work together to turn the promise of SPE into a tangible reality. We can help you navigate the complexities of this technology and bring your vision to life.