ICT Today

July/August/September 2022 I 23 While some ICT professionals are familiar with PoE, there are some key differences with SPoE: • SPoE trades greater reach for slightly lower power delivery, delivering 52 W at 150 m (≈492 ft), 20 W at 400 m (≈1312 ft) and 7.7 W at 1000 m (≈3281 ft). In comparison, PoE delivers up to 71 W over 100 m (≈328 ft). While wireless Ethernet supports many of the connections for BAS, it relies on locally available and expensive to install AC power or battery operation. Looking at the sheer number of IoT endpoints, as well as their density and proliferation, batteries are not prac- tical. The benefits of battery powered sensors will be outweighed by the arduous task of replacing potentially thousands of batteries, leaving them at risk of being abandoned and negating the long-term benefits of the data collection. There are several wired OT protocols that provide both power and data. However, the power solutions are incomplete, and they require high maintenance. Furthermore, canX, an open standard protocol for building control, such as machine to machine (m2m), asks the installer to bear the burden of calculating worst case system loading losses in the cabling and the distribution model. The reliability of device data, especially sensor data, is highly dependent on the reliability of the device connection to the network and its power source. Lost connections can mean the loss of critical data needed for building operations. While wireless connectivity supports many of these connections, wireless is limited in long-term operational viability when the device is powered by batteries. One of the great advantages of Ethernet is its ability • SPoE allows two different output voltages, 55 volts allows for maximum power delivery and 24 volts, which is a more familiar industrial and building automation use case. • SPoE anticipates future low power and very strict standby power requirements by offering a low power standby state, which is two orders of magnitude lower than PoE. to supply power. While four-pair Ethernet offers the right technical performance, the cables are too large and bulky for many building automation applications and do not always support the long cable runs required for sensors and other BAS devices. With thousands of devices and sensors in each building, smaller cables are easier to manage. Single-pair Ethernet offers a variation on PoE called Single-pair power over Ethernet (SPoE) that posi- tions SPE as an ideal cabling mechanism for IoT devices and sensors. Sensor data is already being transmitted to an Ethernet network, either directly or some form of gateway. The IEEE Std. 802.3cg 10BASE-T1 Single-pair Ethernet standard, published in 2019, provides a cost-effective and reliable choice to not only power sensors but also to provide data communications. Single-pair power over Ethernet uses the same playbook as traditional PoE to create an empowerment that is reliable, low touch, and easy to install and maintain. Furthermore, SPoE is very deliberate in the application of power and output. Ports are powered only when connected to a known and interoperable device. If that device is removed, power is very quickly shut off. In addition, SPoE's cabling and power delivery capabilities are predetermined. An installer matches the device requirements to the appropriate cable, and it just works. Moreover, SPoE power networks are both fault isolating and fault tolerant. This means a fault on one portion of the network will not affect the rest of the network. Once the fault is removed, the links return to correct operation. In the event that a device becomes non-responsive, SPE power delivery also provides the ability to perform a remote power-on reset. Power over Ethernet has already demonstrated the benefits of smart power. Now the OT world will be able to fully realize networks that are easy to install, interoperable, intelligent, and robust. The SPoE technology builds on PoE, adding support for greater reach, industry friendly output, voltages, and regulatory compliance.

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