“For over 30-years twisted-pair (TP) cabling has been used to transmit voice, data, and power over the same infrastructure. It has been crucial to integrating operational technology (OT) and information technology (IT) on a single TP ethernet platform during that time as we have seen technological advancements that have expanded the use of the now-ubiquitous TP across domestic, enterprise, and industrial infrastructure,” says Stuart McKay, Senior Business Development Manager at smart network infrastructure firm, Panduit. “TP is now gaining traction as a viable substitute for connecting systems within smart buildings and industrial automation.”
Single pair ethernet (SPE) enables the transmission of data using a twisted-pair of copper wires. Standards have existed for SPE since 2015 but were targeted at shorter-range connectivity landscapes, such as automobiles and industrial systems, where SPE is still popular and standards still evolve. Like vehicles and complex machines, smart buildings demand a core system to link to every sensor and actuator, to provide real-time data and to auto-optimize, while always prioritizing the safety and comfort of occupants/operators. And, while smart buildings require a much greater cabling range, many of the applications in smart buildings have relatively low data transmission demands.
So, five years ago, the Institute of Electrical and Electronics Engineers (IEEE) P802.3cg Task Force began developing a standard to support 10 Mb/s Ethernet over single balanced twisted-pair cabling up to at least 1000 meters for use in commercial and light industrial environments, such as smart buildings. For most process automation, SPE also offers a leap forward in process automation. For decades data transmission rates have been stuck at 31.25 kBit, but the 10BASE-T1L SPE can facilitate 10-Mbit video transmissions from security cameras up to 1000 meters away, which is just not possible with common alternatives, such as Profibus PA.
“Customers are asking building automation system vendors for more Ethernet. It’s a huge smart building enabler that makes data easily transportable, translatable, and more secure,” says Bob Voss, chair of the SPE Subcommittee at the Ethernet Alliance. “Traditional purpose-built disparate systems with their own protocols create a business continuity risk since they are more vulnerable to cyberattack, and the bulk of those that support these systems are nearing retirement. By bringing Ethernet out to the edge of the OT network, these devices can leverage the IT expertise of the many who already know how to secure, maintain, and troubleshoot Ethernet networks—all while providing a common language for building systems to better communicate.”
Ultimately, SPE presents barrier-free data communication from sensors via the LAN to the cloud using the universal Ethernet/IP protocol, thereby bringing barrier-free intelligence from the cloud to edge devices in the smart building. Ethernet/IP already transmits large quantities of (complex) data faster than field bus systems, allowing the collection and distribution of data from the entire network. SPE, however, enables faster data transfer by avoiding gateways for protocol conversions. While built-in authentication and security features offer better cyber security.
“SPE may prove vital to helping integrate IoT into the LAN and connect in-building sensors, systems and devices formerly operating over BACnet or other proprietary fieldbus networks. Using SPE without interfaces to replace the traditional field bus can help realize the high connection density required for the networks of today and tomorrow, and makes installation faster, easier, and more secure,” says Matthias Gerber, Market Manager for Office Cabling at Reichle & De Massari.
“Everything from access management, fire safety and lighting to HVAC, communications and security rely on some kind of Ethernet-based connectivity, and the related devices need to be powered,” Gerber continued. “SPE can help introduce significant cost savings and easier installation in building automation and management. Smart, converged networks also allow energy-conserving technologies and applications to be introduced, such as intelligent management of building space and resources.”
Thanks to the introduction of Power over Data Line (PoDL) a low-power supply is also possible in parallel with data transmission for SPE, opening up a world of IoT opportunities. SPE cabling should be able to provide terminal equipment with up to 50 Watts of electrical power via PoDL, enough for a wide range of smart building sensors and IoT devices. Freeing devices from the constraints of the electrical network in, and around, buildings offers a new level of flexibility to installers and building operators, with the connectivity rates of ethernet bringing smart benefits to a much broader building’s edge.
“SPE, either stand-alone (data only) or together with power, offers numerous opportunities in building automation. Until the ecosystem is fully developed, however, there is still a need for media or protocol converters to upgrade existing systems, as well as challenges associated with the reuse of existing cables and connectors, which may not offer the full distance or speed as defined in 802.3cg,” writes Navaneeth Kumar, in a technical whitepaper for Texas Instruments. “This won’t be a major hindrance, future benefits outweigh the constraints as power-sourcing equipment and power delivery devices for SPE are released in the coming years and we see building automation products increasingly supporting SPE with seamless integration.”