The promises of single pair Ethernet in the industry

Over the past twenty years, Ethernet has gradually taken over the factory floor, becoming the most important networking standard. But the old RJ45 plugs are less suitable for industrial applications. The arrival of single pair Ethernet (SPE) should put an end to this. Marcel Tuit from Weidmüller will during the Industrial Ethernet online knowledge days (from March 23 to 25) provide text and explanation about this new standard.

By: Dimitri Reijerman

The SPE standard has been worked on for a long time, but the time is now ripe to introduce single pair Ethernet onto the market, says Tuit, originally a business development manager for machinery at Weidmüller: “The specifications have been completed and now it is time to high time to bring the product to the market. We at Weidmüller are busy working on this. We are still waiting for a chip that can handle the new standard well. The first test boards are currently being made with these test chips. You also need the right printed circuit board connectors, as well as the plugs and cables, of course.”

As mentioned, it took some time for SPE to gain sufficient support within the industry. Tuit: “It was a somewhat long start-up phase. Everyone looked at each other. Because what if I have a device with single pair Ethernet, who can I communicate with? If you as a company have no influence on the surrounding architecture, this will delay the rollout of SPE. But I also know companies that switch to SPE because they manage their own equipment. That is of course faster, because they immediately see the advantages of a two-wire Ethernet connection.”

One of those advantages is a more solid foundation, Tuit explains: “The old RJ45 plugs, which have been adopted by the industry, are quite fragile. To make these plugs more suitable for industrial applications, the RJ45 connectors have been made sturdier, for example with an extra housing to make them waterproof. The design of the SPE plug shows that it has become a sturdy plug. And much smaller of course: the footprint is up to a factor of five smaller. This leaves you much more space on the print for other things. For example, in a switch that normally houses five RJ45 connections, you can create ten SPE connections. Furthermore, the cables are lighter and less cable material is required, so that costs can be lower in the long term.”

The new standard also enables higher throughput speeds, says the business development manager: “The 10Mbit specification for 100 meters has already been released. But speeds of up to 10Gbit have been achieved over a maximum of 15 meters. The SPE standard has different lengths and speeds than the old industrial Ethernet standards.”

The push for SPE comes from the automotive industry, says Tuit: “More and more parts in a modern car have to communicate with each other with increasing amounts of data. If you can achieve 10Gbit over 15 meters, that is more than sufficient. But in the process industry, for example, you want longer distances, up to 1000 meters. But they can make do with lower throughput speeds. SPE works well there.”

He outlines another advantage for the industry: “Because of the support for longer distances, you need fewer gateways to switch from RS-485 or another protocol to Ethernet, for example. In addition, the footprint of the SPE plug is so small that it physically fits into an M8 connector. And M8 connectors are again widely used with sensors. Ultimately, you get sensors with an IP address that you can address directly over TCP/IP. This is how you ultimately arrive at a network protocol.”

He continues: “During my presentation at Industrial Ethernet, I want to explain the benefits of SPE with concrete examples. Because the plugs and connectors are there, but the development of new prints involves a whole decision tree for many companies.”

And, finally, prices will fall, Tuit expects: “SPE cables are currently even more expensive than traditional Ethernet patch cables, but within a few years we think that prices will drop below that due to increasing volume. After that, its application in industry will be much faster.”

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