For various practical and technical reasons, SPE is a growing force in the networking world, particularly relevant to the realization of the Industrial Internet of Things (IIoT). At the heart of SPE's value proposition is that it offers superior performance compared to existing 4-pair cabling and the traditional IEEE 802.3 Ethernet standard.
SPE operates on twisted-pair cables and can deliver speeds of 10 Mbps over a distance of 1 km, a significant upgrade from the 10/100/1000BASE-T Ethernet standard's maximum speed of 100 meters. This is achieved through the IEEE 802.3g Ethernet standard, also known as 10BASE-T1L. While the BASE-T1 standard was initially marketed for the automotive market, the closer adoption of 802.3g has made it suitable for the smart building and industrial IoT markets.
SPE power and distance
A 1km operating range makes SPE ideal for large-scale industrial IoT implementations, requiring less complex networking equipment to cover large factories or entire industrial sites. However, SPE has another advantage: it uses a single-pair power supply technology similar to PoE to power devices. While PoDL (Power over Data Line) provides relatively low power, around 50W over short distances and gradually decreasing over the entire 1km, it is still beneficial for industrial IoT devices designed to operate within a low power footprint.
Lighter, thinner, and cheaper
The benefits of CAT6 cabling are also significant. A new Industrial IoT project may require a large number of new cables. However, since SPE only requires a quarter of the physical cable (one pair instead of four), costs can be significantly reduced. Furthermore, SPE cables are only a quarter the weight and diameter of conventional cables, allowing for better utilization of existing conduit space and reducing weight support requirements. Finally, SPE can often retrofit existing four-pair copper cables, further reducing installation costs.
Network topology standardization
A key reason for industry interest in SPE is that it offers the opportunity to standardize network protocols across the entire network. Previously, Ethernet had been the de facto standard for the vast majority of enterprise networks, but not at the so-called "field" level, where various bus systems were commonplace.
Traditionally, one reason for this is that BUS systems only require two pairs of cables instead of the older four-pair Ethernet cables, resulting in significant cost savings when considering the thousands of sensors and actuators throughout an industrial installation. This standardization means that the gateway arrays currently used to bridge the Ethernet-bus gap will no longer be needed, greatly reducing the burden on those maintaining this often-customized legacy software.
Standardization: Security Risks?
Standardization does indeed raise new considerations for future SPEIIoT deployments—security. Traditional industrial automation systems running serial bus technology effectively isolate field devices from the rest of the network. Switching to SPE means that field devices will have to undergo the same scrutiny as any other connected enterprise hardware, inevitably requiring occasional OTA (over-the-air) bug fixes, protocol updates, and so on.
Fortunately, with the bandwidth and power delivery of SPE, newer SPE-compliant devices shouldn't be technically limited by traditional IIoT OTA barriers. However, any older devices may not be so easy to manage. Pure Ethernet also has the advantage of avoiding many of the security challenges of wireless alternatives, although primarily from a local interception perspective.
Disconnector standard
There are other obstacles to adopting SPE, such as the common standardization issue. While SPE and the IEEE 802.3g Ethernet standard have been established, the problem lies at the connector end, with two different connector implementations already on the market. Both are standards-based. The SPE Industry Partner Network promotes the T1 interface defined in IEC 63171-6, while the SPE Systems Alliance currently supports IEC 63171-2. The future remains uncertain—whether one connector will be accepted across the industry, or whether the two connectors will continue to coexist, perhaps in specific vertical sectors—these questions will be answered in the coming months.
The SPE Industrial Partner Network includes Harting, TE Connectivity, Hirose, Amphenol ICC, and Molex. Meanwhile, the SPE Systems Alliance has PhoenixContact, Weidmüller, and SICK as its supporters. The two organizations also have different focuses: the network focuses on industrial applications, while the alliance looks at various sectors including automotive and smart buildings.
SPE has a bright future.
Clearly, SPEs can offer a wide range of services for Industrial IoT deployments, as well as the automotive and avionics industries. While connector clutter may hinder adoption in the short term, the long-term future looks bright. Looking ahead to the demands of increasingly interconnected manufacturing and infrastructure supply chains, it's evident that a unified Ethernet network providing robust connectivity and power for Industrial IoT devices will be a compelling concept for Industrial IoT deployments for some time to come.
