22 Jul 2024


Groups vie to offer single-pair Ethernet connectors

Harting says that T1 connector is the first to be fully standardised for SPE duties

At the recent SPS show in Germany, two groups of companies were trying to persuade visitors to that they had the connector technologies needed to make industrial applications of single-pair Ethernet (SPE) a reality.

SPE is intended to overcome limitations with existing industrial Ethernet cabling and connectors. Using just one pair of conductors, instead of two pairs or four, SPE will support scalable, deterministic networking from sensors to the cloud.

One group, calling itself the Single Pair Ethernet – Industrial Partner Network, is based on a collaboration announced at the 2018 show, consisting of Harting, TE Connectivity and the Japanese connector-maker, Hirose. Since then, it has attracted four new members – Würth Elektronik, Leoni, Murrelektronik and Softing IT Networks – to establish the new partnership.

Harting has developed an interface called T1, claiming it is the first fully standardised SPE interface for industrial applications. It is based in the IEC 63171-6 standard which, the company says, has been established as the SPE mating face for industrial applications by both global and US standardisation bodies (ISO/IEC, JTC 1/SC 15/WG 3 and TIA TR42). This decision, it adds, is also supported by IEEE 802.3.

Harting is planning to produce both IP20 and IP65/67 versions of the T1 connection using snap-in technology, as well as M8 and M12 versions that use screw or push-pull locking to create socket, connector and cable assemblies. The connectors will be suitable for SPE cables up to 1km long and will support data rates up to Gigabit.

In the second SPE camp are Phoenix Contact, Weidmüller, Reichle & Massari (R&M), Telegärtner and Fluke Networks. They are developing IP20 SPE connectors that comply with IEC 63171-2 and IP67 versions that comply with IEC 63171-5. (IEC 61371 defines six connectors with different mating faces, dimensions and mechanical properties.)

Weidmüller says that compared to other interfaces, the IEC 63171-2 and 63171-5 connectors are “extremely compact, offer optimum RF performance, and even have a dielectric strength of up to 2.25kV DC”. The connectors can be used with conductors with AWG cross-sections from 22–26. The M8 connector mating faces can be designed to be both male and female, allowing “free” couplings to be achieved, and eliminating the need for extension cables that have only plugs or sockets at either end. By using the same mating interface, it says, both can be freely combined, resulting in fewer components being needed.

Weidmüller adds that its compact connectors are half the size of an RJ-45, allowing two single-pair Ethernet ports to be installed in the same space as an RJ-45 PCB connector, doubling port densities. Despite its size, the mechanism is robust, requiring an extraction force of at least 50N.

A final attraction, according to Weidmüller, is that SPE could be used to supply devices with up to 60W of power using the PoDL (Power over Data Line) technology. It could therefore provide sensors with both power and a data interface, even in cramped locations. PoDL could also be used in potentially explosive environments, making SPE attractive for process applications.

In addition to the connectors, SPE also needs suitable cables and one manufacturer offering to fill this gap at SPS was Nexans, which has developed a twisted-pair SPE cable as part of its Motionline portfolio, that is suitable for connecting small devices and for drag chain applications. The UL-approved cables have EMC shielding to protect the signals from interference, and a polyurethane jacket to withstand exposure to oils and chemicals.