Cree and Cisco tie up for PoE smart lighting

Cree has joined Cisco’s Digital Ceiling ecosystem, offering Ethernet-powered smart lights.

The Cisco partnership includes other light makers, plus hardware, middleware software and data analysis companies – Phillips and Microchip are among the members.

LTG-SmartCast-CR Series Troffer - Cree and Cisco tie up for PoE smart lightingCisco sees a future for smart buildings where there are no mains power cables in a ceiling, only Ethernet cables connected with RJ45 plugs.

These cables will connect with lighting, and sensors for: ambient light level, human presence, temperature or carbon dioxide. Data capability could come from Bluetooth tranceivers or ‘Li-Fi’ optical links via the light fittings.

Sensors would connect back to building networks handling heating, air conditioning and security, for example.

And the sensor data could be analysed. “They become valuable data sources for information across your environment that you can analyse and act upon to improve business outcomes,” said Cisco, whose interest in all of this is that it sells power-over-Ethernet (PoE)-enabled Ethernet hardware.

Cree’s part in this does not extend as far as Li-Fi data communications, Cree vice-president of marketing, Greg Merritt, told Electronics Weekly, but does include PoE-powered luminaires with integrated sensors – at the moment for occupancy and ambient light levels.

The products will be based around Cree’s existing SmartCast brand wireless smart lighting system which links lighting, sensors, wall switches and wall dimmers.

A unique aspect of SmartCast is the way it auto-configures after the lights are first installed, said Merritt.

Every light in the installation – a whole building, for example – is triggered to blink a code using its LEDs, at the same time as receiving codes from other lights through its ambient light sensor.

Software then partners lamps into groups depending on whether they can detect one another’s codes or not.

“The vast majority of spaces will auto-configure”, said Merritt.

Where they don’t partition correctly, within a glass-walled office for example, they can be reconfigured by someone walking around with a hand-held controller. “Think intuitive TV remote control,” said Merritt. Conference rooms are spaces that will need to be reconfigured after auto-configuring, to get the front lights to turn off separately, he added.

The Ethernet version of SmartCast has been introduced alongside the wireless version. “Now you can configure a whole building with a single keystroke,” said Merritt.

That said, there is no bridging facility between wireless and Ethernet SmartCast at the moment.

Although the ceiling space can be all-Ethernet, wall switches and dimmers also need an Ethernet cable, so Cree sees wired SmartCast as a solution for what it calls ‘deep retrofits’ for buildings or new-builds.

“No high-voltage in the ceiling at all, said Merritt, “but you will still have mains voltage in the building for plug loads and the PoE switches.”

And he sees local refits as another market: “Maybe you will just do a conference room”, or in reconfigurable spaces where lights can be re-positioned without having to disconnect mains wiring – so no special training required. Safety is further increased by the power sources only feeding power into the cables after a handshake procedure.

One of Cree’s arguments to building owners reluctant to step away from conventional wiring is that energy and maintenance savings will cover the cost – as lights turn themselves off in unoccupied rooms and throttle themselves back when natural light is coming in through the windows.

Another argument is that having sensors at 3m intervals across the ceiling in every room has building management advantages, some of which might not have been thought of yet, and that facilities such allowing occupants to choose the colour temperature of their own lighting increases acceptance.

Certainly one organisation has committed, as Mobile County Public Schools in Alabama recently deployed the technology in their administrative offices, with plans to implement it in classrooms this spring,” according to Cree.

“Beyond energy efficiency, we now have the ability to tune the colour of our lighting to create custom, comfortable classrooms. It is also adaptive, allowing for future security enhancements such as signaling a school emergency,” said Mobile County School System IT manager David Akridge.

Something else that interests Cree is Cisco’s proprietary UPoW system that can feed loads of over 50W, in contrast to the official PoE and PoE+ standards, which are 1W5 and 30W respectively. “Most troffers are around 4,000lm, that’s close to 40W,” said Merritt.

Power-over-Ethernet started as a scheme for using spare pairs in a cable for power. 15W IEEE 802.3af PoE and 30W 802.3at PoE+ both use two spare pairs – the latter with some de-rating for the higher cable temperatures seen in cable bundles.

There have always been ways to mix data and power on the pairs, and this becomes essential with UPoE, which uses all four pairs in a Cat5e cable.

While Cree speaks of energy efficiency, it is worth noting that, due to the higher currents involved and thin conductors, the Ethernet cables themselves waste more power than conventional mains wiring – particularly compared with European 230V wiring – see table below.

The solution was announced at Cisco Live! in Berlin this week, it will be commercially available in the second quarter of 2016.

– simplified data
Cable type Cat5e Cat5e Cat5e
IEEE standard 802.3af 802.3at Cisco
Max source power 15.4W
Max load after
cable loss
12.95W 25.5W 51W
Twisted pairs used 2 pairs 2 pairs 4 pairs

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