Power over Ethernet bridges the gap between digital ceiling and smarter building

The right PoE technology delivers Layer 2 management while ensuring uninterrupted performance and power efficiency.

1811ciminternetofthings Photo 1
The right PoE technology delivers Layer 2 management while ensuring uninterrupted performance and power efficiency.

By Galit Mendelson, Microsemi Corp.

Demand is growing for digital ceiling applications, which include network-powered LED lighting solutions and the elements required to add connected lighting in buildings’ systems into the Internet of Things (IoT). These digital ceilings centralize lighting, building automation and analytics for predictive maintenance, among other capabilities. As they do, they are transforming enterprises and driving new opportunities for a wide variety of solutions that improve efficiency and comfort while enhancing sustainability and reducing costs.

To deliver these benefits, digital ceilings need the necessary enterprise IoT connectivity to combine all required network-powered sensors and WiFi access points as well as the facility’s HVAC system controls and surveillance cameras. They also must incorporate the latest Power over Ethernet (PoE) technology to deliver remote Layer 2 management while ensuring uninterrupted performance and much greater power efficiency than was previously possible with the prior generation of solutions.

Microsemi’s PDS-208G fanless digital ceiling Power over Ethernet switch centralizes power management. It supports full power mode by providing 30W over 8 ports simultaneously, and enabling any individual port to operate at up to 72W.

Getting started

An ideal first step toward implementing a digital ceiling is to use network-powered luminaires. This takes advantage of existing LAN infrastructures and enables remote lighting management capabilities with lower installation and operating costs. PoE is a key enabling technology for creating a flexible solution of this kind without the need for AC wiring. Instead, the network-powered LED luminaires are connected to and powered from the corporate data network, enabling IT managers to control and optimize power utilization as a part of network management.

Another advantage of PoE technology in this scenario is that IP-enabled powered devices (PDs) can be installed in the digital ceiling without the need for electric power infrastructure. These PDs can include IP telephones and cameras as well as wireless LAN access points and other IP-based terminals. Each receives power in parallel to data over the existing Ethernet infrastructure. Meanwhile, the structured cabling is protected and the PDs don’t interfere with concurrent network operation.

In general, PoE simplifies installation when used with network luminaires, saving capital expenditures (capex) and operational expenditures (opex) while delivering many valuable new capabilities. It also supports a unified and safe power standard for worldwide use. Now, as organizations take the next step beyond network luminaires toward implementing digital ceilings, PoE is also supported by a new standard created specifically to meet the higher power requirements of the digital ceiling as well as the need for more-efficient power management.

To deliver benefits to building owners and users, a digital ceiling environment needs enterprise Internet of Things connectivity to combine all required network-powered sensors, WiFi access points, sensors and other systems. The environment also must incorporate Power over Ethernet technology to deliver management and power efficiency.

Transitioning to digital ceilings with new PoE standard

PoE technology moved into many new applications and steadily evolved since the 2003 ratification of the PoE standard. At the same time, PoE use has grown through the implementation of each new standard, from IEEE 802.3af through the IEEE 802.3at, IEEE 802.3bt, and HDBase-T standards.

The latest IEEE 802.3bt standards support PoE’s use in digital ceiling applications by increasing maximum available PoE power. The new standard also adds smarter “Automatic Class” functionality and improves reliability by unifying the power and control layers. Each of these features of the new standard delivers valuable benefits.

  • Higher maximum power—IEEE 802.3bt redefines power levels up to 90W. This is accomplished by using all four pairs of the structured wiring.

  • Automatic Class functionality—The IEEE 802.3bt standard allows the power sourcing equipment (PSE) to determine the actual maximum power drawn by the connected PD. The PDEs first measure the power consumption of the connected PD throughout a defined period and then set the maximum power output based on the power drawn during Auto Class plus margin. The PSE can also allocate leftover power to additional light bulbs if it knows that a specific LED luminaire will draw less than its class power, which is particularly beneficial to the digital ceiling application. This optimizes power consumption to significantly reduce cost.

  • More robust power management capabilities—IEEE 802.3bt also solves the challenge of enabling more-efficient PoE delivery systems even as it supports higher power. It delivers more robust power management capabilities by expanding the power classification information that is exchanged during initial negotiation while also supporting multiple PoE classes and ensuring backward-compatibility.

  • Improved reliability—The new PoE standard also unifies the power and control layers. Unlike traditional lighting installations, in which power is provided via the AC network and the control is performed via separate dedicated lines, the digital ceiling architecture as defined by the IEEE 802.3bt standard offers both functionalities through the LAN. The power is provided via DC PoE power while the control data is provided via the standard Ethernet protocol.

Reliability is particularly important for this unified network. It must deliver high power efficiency specifically in no-load and in full-load scenarios, and it should offer basic Ethernet connectivity now and, in the future, 10/100/1000-Mbit/sec data rates for emerging and other enterpriseapplications.

To deliver these benefits, the network needs to support a distributed architecture in which each individual switch is installed close to the lights. This reduces power losses over the cables. It requires that the PoE switch for digital ceiling installations be plenum-rated and support 6 to 12 PoE ports per switch to power lights for 1 or 2 rooms.

Other PoE requirements

One critical requirement for using PoE in digital ceilings deployed for smart buildings is support for full-power mode for all the ports simultaneously. The solution also must ensure energy-efficient operation with maximum power loss savings on the Ethernet cables duringtransmission.

Solutions are available that support full-power mode by providing 30W for 8 ports simultaneously and enabling any individual port to operate at up to 72W. An example is the Microsemi PDS-208G fanless digital ceiling PoE switch. All ports remain active even while the device is performing software upgrades, and the switch centralizes power management to simplify setup and maintenance. Unlike enterprise switches, it delivers power and data to lighting fixtures and other Ethernet terminals over standard Ethernet cables as efficiently as possible.

Many applications will require that the PoE solution be deployed in the digital ceiling. To do this, the switch must fit inside the available ceiling space. This is often only possible if the switch supports fanless operation, which also reduces noise and associated disruption to the office working environment. To accommodate heavy demand for powerful wireless access points and data-intensive mobile applications, PoE switches should also support a wide variety of WiFi-based devices. They also should support network data rates of 1000 Mbits/sec or higher for the latest 3G/4Gtechnologies.

A final set of considerations includes whether the solution’s installation can be completed quickly, easily scaled, and managed remotely over the network. It should be compatible with all available IP-based PoE luminaires and support multiple building systems beyond network-powered LED luminaires. This includes, but is not limited to, IP-based sensors and surveillance cameras as well as WiFi access points and HVAC system controls. PoE solutions that use the latest technology will optimize network planning and power consumption while delivering required flexibility.

PoE technology is helping to set a course for smarter buildings that feature enterprise-grade IoT connectivity. It is playing an important role in empowering digital ceilings that connect multiple systems such as lighting and building automation over a single IP network to help improve workplace productivity and create a more-capable facility infrastructure that is easier to scale and maintain.u

Galit Mendelson is senior director of PoE marketing for Microsemi Corp.

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