Single Pair Ethernet – a flash in the pan or a revolution?

Andreas Muckes | 11. May 2020

About 4 years ago, companies wrote the information “Industry 4.0” on just about everything. Every magazine, every website and every advertising mail used this term. It seems to be similar with the three letter term SPE (Single Pair Ethernet).

Apparently everyone is talking about SPE and it feels a bit like a trend. But does the technology actually have the potential for more? One major difference already exists today: In contrast to Industry 4.0, Single Pair Ethernet has a clear definition. The technology is largely transparent. Or is it …?

An attempt to say the simple words …


There are so many bus cables after all, so why have one more technology? Here you have to go back a little into the history of the eighties. It was then that the need for bus technology arose in the car. Until that time, signals were transmitted in the car with relays and switches. New functions in the car required data transmission, so a group of companies around Bosch developed the revolutionary CAN bus. Data transmission with this bus is safe, robust and proven. Today, this system is reaching its limits because our vehicles require significantly more data volume. With the demand for new vehicles, such as autonomous driving, the birth of Single Pair Ethernet was inevitable, as it were. The requirements for the new bus system were the same as in the eighties: robust and safe. However, a high data volume was now also required. The industry also wants to take advantage of these positive attributes and the system is being adopted by leading technology companies.


How can so many companies in the industry come together at one table?

In contrast to the automotive industry, there is a long-prevailing trend in industry to use Ethernet derivatives in the fieldbus area. Standards like Profinet, Ethercat or CC Link IE are already established and excel in performance and popularity. Furthermore, cables and connectors are clearly defined. How to improve this standard while keeping it clear enough that millions of users can reliably combine different products?

This requires a network of companies that define standards. This has been accomplished in the Industrial Partner Network. Here, companies from different areas, which need a good bus system, work together. Network specialists for products such as IC’s, magnetics, cables, connectors and measurement technology were identified. They all carry out research and development in their field in order to contribute knowledge towards the overall result. We at igus are doing our part of the pioneering work in the field of durable cables for movement.


What should the new bus system do differently or better than its current “competitors”? The amount of data must continue to be high, it must be reliable and the interface must be defined.

What should the additional advantage be? There are two basic requirements that need to be met. It must become cheaper than today’s four-pair Ethernet solution, as more bus systems are to be used for machine data. At the same time, one must not lose sight of the overall costs.

But the biggest demand is the reduction of the installation space. Here, today’s CAT5e technology, with its large connector solutions and thick cables of around 8mm, is not well suited to accommodate bus systems in every area of the machine. With SPE there is a 25% advantage in diameter for cables and well over 35% for connectors.

This clearly defines the great advantage of the system: lower costs and less installation space. It becomes possible to bring the bus technology even to the smallest sensor in any machine. This is the basis for Industry 4.0 in its purest form.


Sounds great, when will I be able to use SPE?

This is not the end of the road, but the main hurdles have been overcome. The rules were clearly referenced in IEEE802.3.

In order to create planning reliability for users, IEC 11801 and TIA TR42 have technically confirmed the standard of the Industrial Partner Network with its partners. This means that control system manufacturers and sensor manufacturers can now build on this safety and integrate the technology into new applications. It is expected that the first devices with the technology will be available on the market by the end of the year.

We at igus want to do our part of the groundwork for this new technology and are involved at an early stage with our CFBUS.PUR.042.

chainflex cable CFBUS.PUR.042

For further development, we continue to rely on an active exchange with customers and expressly request this. Do write to us and we will find a solution together with you.

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