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A Primer on Lighting Control Systems

While LED lights have revolutionized the lighting industry, adaptive, controllable light systems are also adding flexibility and efficiency. From simple photocell systems that turn lights on and off depending on outdoor light levels to bi-directional communication control systems, adaptive systems offer many advantages.

“Think back 30 years,” says Landscape Forms Lighting Innovation Specialist. “All the lights in a parking lot at a public park would run at full intensity all night and then turn off at dawn. It took a lot of energy and dollars to light that empty parking lot.” Now cities can save energy and costs with systems that dim the lights when the park is less likely to be used. And that’s only one of the ways in which control systems are changing the programming and maintenance of lighting.

We spoke with Annie Kuczkowski, a lighting engineer with Colorado-based Clanton & Associates, who shared her knowledge of today’s control systems and where they’re headed.

Basic control systems have been around for a long time. A photocell system applies a simple on/off function based on how much light it senses. Photocell systems can be installed on any exterior project, and often on streetlight projects.

The astronomical time clock is typically used in parks. First, the photocell turns lights on before dusk and at a certain time all the lights turn off. This is a time-based, hard on/off system.

Motion sensors are often paired with photocells, though motion sensors can be paired with any control system on the market. These systems sense a lack of activity or movement and dim lights. After a continued period of inactivity, lights are further dimmed or turned off. The availability of LED technology has led to advances in motion sensors. Previously, these systems depended on bi-level dimming of a ballast, which was expensive. LED fixtures with 0-10 volt drivers dim light by modulating the voltage and offer more than two dimming choices.

Urban transportation and energy departments that are managing vast networks of power and lights are benefitting from the availability of LED technology and adoption of dimming drivers.

Driver-enabled control systems get more complex than these basic systems. Depending on the quality of the driver, drivers can provide different capabilities for how low they dim. A 0-10 volt dimming driver dims down to about 10 percent before the LED starts flickering. Higher quality and more expensive drivers can dim to a very low one-percent output. This application might be used in high-end spaces, such as hotel terraces. Kuczkowski recommends 10-percent dimming when installing new outdoor lighting systems, a good light level for any streetlight, under-deck lighting, or parks with pedestrian light applications.

The zero to ten volt dimming system are the most common type used in the United States. Digital Addressable Lighting Interface (DALI) control systems are the most common type in Europe, though they are gaining traction in the United States due to availability of products from international manufacturers such as Signify. The DALI system enables bi-directional communication. For example, the control directs a specific output percentage to a luminaire and then the luminaire sends back a signal that it is dimmed to that output. DALI systems are often used in plazas or parks where different lighting accents are installed. But this system can be used for everything from streetlights to decorative bridge installations.

The last common type of dimming protocol is DMX. This system was first used in theatres, but now it is found in park and plaza applications. DMX enables artistic lighting designs, such as bridges with lighting chases or color changing luminaires. Each luminaire can be assigned to a different channel, so the lighting schemes can change to create dramatic effects.

That’s a basic explanation of the control systems available today. What excites Kuczkowski is how control systems are being used and the value they offer.

Asset management control is the future of lighting control systems. A wireless controller module, or node, is placed on the top of a fixture and connected to 5- or 7-pin control receptacle, enabling each luminaire to connect to each other and to a central management system through cellular or radio frequency. This control node can monitor everything about the light, such as input voltage, kilowatt usage, even gauging its life. The system could alert a facilities manager that a specific light is out, sending the maintenance person to that exact location. Some control systems are so sophisticated that managers can access the system from their phone, tablet, or computer to change lighting levels. The controller can increase light levels during an emergency or completely turn off lights as a safety measure, such as prior to police entering a building in response to a threat.

Asset management control systems are a perfect example of a need waiting for the technology, says Kuczkowski. The return-on-investment for cities, she adds, is tremendous.

Asset management systems cut down on labor costs and improve safety. If an issue can be identified prior to sending out a maintenance team, the crew can stock its vehicle with exactly what is needed for repair. But Kuczkowski believes the biggest savings is in liability costs. If maintenance staff is immediately aware that a light pole is knocked down, the crew can go to that location immediately instead of waiting for a pedestrian to notify them. The accuracy of location and quick response time also cut down on labor costs and improve worker safety.

Whether monitoring water meters, streetlights, community-wide Wi-Fi or 5G cellular applications, this management control system is a necessity for any smart city. The benefits are driving adoption of asset management installations by cities, power companies, and energy-related organizations. Los Angeles has implemented an asset management system and Chicago is in the process of doing so. Xcel Energy, Florida Power, and DOTs are also implementing asset management systems, and ASHRAE and IECC are beginning to require exterior control applications related to night dimming and light level reductions.


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