Single pair ethernet useful in buildings
By Matthias Gerber, Market Manager Local Area Networks
Friday, 23 April, 2021
Single pair ethernet is creating high expectations. Where can the new technology unroll its benefits?
The key technology in the Internet of Things
Expert authors are reporting on revolutionary potential. Single Pair Ethernet (SPE) will open up new dimensions in EtherNet/IP data transmission, they say. Experts agree: SPE is becoming an application-independent, inexpensive key technology in the Internet of Things (IoT) and Industrial Internet of Things (IIoT).
SPE requires — as the name suggests — just one twisted pair for data transmission. A thin two-core cable and a small connector are all that is needed for the cabling. The link distances range between 15 and 1000 metres. The bandwidth spectrum ranges from 10 Mbps to 1 Gbps. SPE cabling should be able to provide terminal equipment with up to 50 watts of electrical power via Power over DataLine (PoDL).
Standardisation process ongoing
Several committees are working at high pressure on the standards. Various connector systems have been specified. IEEE has defined six transmission protocols and four transmission distances. But neither the influence of remote power supply nor the implementation of multi-drop capability has been adequately addressed so far (at the time this article was written in Q2 2020).
So much for the current framework conditions. With regard to expectations, the following should be noted above all:
- SPE should not and cannot replace the universal RJ45 network interface. We at R&M see SPE as an extension to RJ45.
- SPE can replace field bus technology. However, it is not suitable for the application-independent LAN infrastructure in buildings, for broadband data transmission or even for the backbone in local data networks.
- There is currently no uniform solution for the connector systems. R&M supports the most suitable solution for an application. This can be one of the connector systems defined by the standardisation but does not have to be. For industrial applications, R&M advocates the aims of the SPE System Alliance but the company is keeping all options open when it comes to building automation.
If you look deeper into building cabling, useful and promising application possibilities arise. Specifically, we are referring to the digital ceiling, structured ceiling cabling and digitalised building automation.
Single Pair Ethernet could connect many small IoT applications with the EtherNet/IP data network via the service outlets of the digital ceiling zones. For example:
- Light, temperature, smoke and air sensors.
- Controls for windows, locks and blinds.
R&M recommends two models for cost-effective, rapid integration of SPE in Digital Ceiling (see figure). A 10Base-T1 switch is used as a bridge between SPE and LAN. It is positioned either in the zone or in the floor distributor. R&M describes further specifications in the specialist magazine Connections No. 58.
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