Although single pair Ethernet (SPE) has existed for some time, and despite the potential benefits of this technology, the road to adopting this technology is not completely smooth. Due to various practical and technical reasons, SPE is becoming more and more powerful in the network field, and has particularly relevant attributes for iiot implementation. The core of SPE’s value proposition is that it provides better performance than the existing 4-Pair cables and the traditional IEEE 802.3 Ethernet standard.
SPE operates through a single twisted pair cable and can provide a speed of up to 10Mbps over a distance of up to 1km, which is significantly higher than the maximum 100m speed under the 10/100/1000base-t Ethernet standard. This is through the IEEE 802.3cg Ethernet standard, namely 10base-t1l. The original market of base-t1 standard is the automobile market, but the recent 802.3cg makes the standard applicable to the intelligent building and iiot markets.
SPE power and distance
The working distance of SPE is 1km, which makes SPE very suitable for realizing industrial Internet of things in a larger area. It requires less complex network equipment to cover large factories or complete industrial sites. However, SPE also has another trick. It uses single pair power supply technology, just like Poe, to provide power for equipment. Although podl (data line power supply) can only provide relatively low wattage, which is about 50W in a short distance, and the wattage will gradually decrease within the full length of 1km, it is still advantageous for iiot equipment designed to operate within the low power consumption range.
Lighter, thinner, cheaper
The advantages of CAT6 cabling are also significant. A new iiot project may be expected to install a considerable number of new cables. However, since the SPE requires only a quarter of the overall physical cable (one pair instead of four pairs), the cost can be significantly reduced. The weight and diameter of the SPE cable is only one quarter, which can make better use of the existing pipe space and reduce the weight support requirements. Finally, SPEs can typically run on existing 4-Pair copper cables, further reducing installation costs.
Network topology standardization
A key reason why the industry is interested in SPE is that it provides an opportunity to standardize network protocols throughout the network. In the past, Ethernet has been the de facto standard for most enterprise networks, but this is not the case at the so-called “field” level, where various bus systems have become common.
Traditionally, one of the reasons is that the bus system only needs two pairs of cables instead of the old four pairs of Ethernet. Therefore, when considering the thousands of sensors and actuators in the entire industrial device, it can greatly save costs. This standardization means that a series of gateways currently required will no longer be needed to bridge the gap between Ethernet and bus, which gives a sigh of relief to those who maintain this kind of software, which is often referred to as traditional software.
Standardization: safety risk
Standardization does present a new consideration for future SPE iiot deployments security. Those traditional industrial automation systems running serial bus technology effectively isolate field level devices from other parts of the network. Switching to spe means that field level equipment will have to accept the same review as any other connected enterprise hardware, and it is inevitable that OTA (over the air) error repair, protocol update, etc. will be carried out irregularly.
Fortunately, with the SPE bandwidth and power transmission, newer SPE compliant devices should not be subject to the technical limitations of the two obstacles of the traditional iiot Ota. However, any traditional equipment may not be so easy to deal with. Pure Ethernet also has the advantage of avoiding the security challenges of many wireless alternatives, although mainly from the perspective of local interception.
Open circuit connector standard
There are other obstacles to the adoption of SPEs, namely, the familiar standardized form. Although the SPE and IEEE 802.3cg Ethernet standards are mature, the problem lies in the connector side. There are two different connector implementations in the market. Both are standards based. The SPE industrial partner network promotes the T1 interface defined in IEC 63171-6, while the SPE systems alliance currently supports IEC 63171-2. The future development prospect is still uncertain – whether one connector is accepted by the whole industry or whether the two connectors will continue to coexist. Perhaps in specific vertical fields, these questions will be answered in the next few months.
Members of the SPE industrial partner network include HARTING, te connectivity, Hirose, Amphenol ICC and Molex. Meanwhile, supporters of SPE system alliance include phoenix contact, weidm ü ller and sick. The two groups also have different focuses. The network focuses on industrial applications, while the alliance looks at various fields from a broader perspective, including automobiles and intelligent buildings.
The bright future of SPE
Obviously, SPE can provide many things for iiot deployment, as well as automotive and Avionics departments. Although connector confusion may inhibit adoption in the short term, the long-term prospects are bright. Looking forward to the requirements of the increasingly interconnected manufacturing industry and infrastructure supply chain, it is clear that the unified Ethernet that provides powerful connection and power supply for iiot equipment will be a very powerful concept in iiot deployment in the future.