Craig DiLouie, LC recently interviewed Mike Crane, senior product manager for Hubbell Building Automation, for tED Magazine on the topic of wireless RF lighting control. The interview is published here in its raw form.
DiLouie: How would you characterize demand for RF wireless lighting controls in both new and existing commercial buildings?
Crane: Over the last few years, the interest in wireless lighting controls in the commercial market has seen a major increase, primarily due to changes in new energy codes and regulations like ASRAE/IESNA 90.1, California Energy Commission (CEC) Title 24, USGBC LEED (Leadership in Energy and Environmental Design) and International Energy Conservation Code (IECC). These code changes are requiring the use of energy saving lighting controls and the most cost efficient way to implement these controls, especially in existing commercial buildings, is to use wireless controls.
DiLouie: What is the history of the technology? How did we get here?
Crane: Wireless RF lighting controls primarily got its start in the residential market. With the creation of robust and reliable radio-based technologies like Zigbee, EnOcean and SNAP, developing and providing commercial solutions is now possible. Although the technology has been around for a while and the demand is increasing, we are still at the very early stages of adoption within the commercial market. There is a now a growing number of wireless lighting control providers today which provide niche solutions (e.g. parking garages, outdoor lighting only, indoor only, etc.). As the technology becomes more pervasive in the commercial market, major manufacturers will focus on being “one stop shops” by providing complete solutions for all lighting applications – indoors and outdoors. These bundled solutions will include all forms of luminaires with wireless controls built in.
DiLouie: What are the benefits of RF wireless lighting controls?
Crane: RF wireless lighting controls provide many benefits. They can be easily added to existing lighting systems wherever needed without having to worry about changing existing wiring. This is especially important when dealing with the wiring challenges associated with hard ceilings or outdoor lighting. Another benefit is flexibility. Wireless lighting controls provide the ability to configure and fine tune lighting at anytime based on the customer’s lighting and control requirements. Wireless controls also provide cost savings by eliminating the need for expensive dedicated low voltage control communications wiring.
DiLouie: What are ideal applications for RF wireless lighting controls? In what types of environments do they work best, and in what types of environments can operation prove more challenging?
Crane: Ideal applications for RF wireless lighting control include: classrooms, offices, warehouses, hotel rooms, area/site lighting, parking garages, roadway/street lighting, remote sport fields, auto dealerships, remote parking facilities and fairgrounds/parks. Challenging environments for wireless controls include buildings where there are a lot of reflective building materials which may block or adversely affect radio communications. This would include machine rooms and other areas that contain a lot of reflective metal and steel.
DiLouie: What are the types of RF wireless lighting controls that are available?
Crane: There are two types of RF wireless lighting controls available – actuators and system input devices. Actuators are the relay-based devices that provide the on/off switching control as well as the 0-10VDC full-range dimming control. Actuators are responsible for the implementation of the lighting control strategy. They receive commands from the system input devices and take the appropriate action based on a set of control rules. System input devices include occupancy/vacancy sensors, photo-sensors, and switch stations. These input devices monitor changes in occupancy, light levels and broadcast those changes, along with end user switch input, to the actuators.
DiLouie: LED luminaire manufacturers have begun integrating RF wireless lighting controls in some of their products. What are the advantages and disadvantages of implementing lighting controls at the luminaire?
Crane: The major advantage is that customers now have one stop shopping. They no longer have to pick a luminaire from one manufacturer and a control solution from another manufacturer and hope that they work together. Integrated luminaire/control solutions are typically tested together by the manufacturer to ensure compatibility. Another advantage of integrated lighting controls is that it provides individual luminaire control, which in turn provides the most energy savings, by only turning on those luminaires that need to be on. An example of this is a warehouse where the items that are picked the most are placed at the beginning of an aisle. Instead of turning on the entire row of lights with a single occupancy sensor, wireless lighting controls in each fixture would only turn on the fixtures in that row where the occupant travels. The only disadvantage of implementing lighting controls at the luminaire is that the cost of the luminaire may be slightly higher due to the additional control component(s).
DiLouie: How are RF wireless lighting controls typically scaled from room-level control to networked rooms to entire buildings?
Crane: To scale wireless lighting controls from room-level control to networked rooms to entire buildings requires that the controls have built-in networking support which can be enabled through a programming interface. These types of devices typically have out-of-the-box functionality that doesn’t require any external software program. An actuator is put into “learn mode” by pressing a button on the device and is then paired with a system input device (e.g. a switch station) by pressing a button on it. While in the learn mode, the actuator can continue to pair up with additional input devices (e.g. occupancy sensors and photo-sensors). To scale this simple room-level control to a networked room or entire building, that same actuator must have support to receive radio commands sent to it from a wireless network programming device which will then place the wireless actuator and system input devices into their appropriate network groups.
DiLouie: What opportunities and solutions are available taking advantage of two-way communication for performance monitoring, maintenance and analytics?
Crane: Many of the wireless systems today include actuators and/or control modules that feature a Hall Effect sensor that is used for current sensing. This allows metering information (e.g. Current amperage, volts, KWh, KVAh, lamp burn time, ballast burn time, etc) to be retrieved and analyzed. Based on these types of parameters, alerts and notifications can be created when specific thresholds are reached.
DiLouie: How secure are wireless lighting control networks to hacker intrusion and mutual interference with other wireless signals in the environment?
Crane: Wireless lighting control systems are very secure and multiple security measures are used to prevent hacker intrusion or interference from other wireless signals. One of the security measures used is Spread Spectrum Frequency Hopping (an FCC requirement for many large-scale wireless lighting control systems). Wireless devices constantly hop through a range of frequencies where they receive a message packet on one frequency and then retransmit that packet on a different frequency. This prevents a hacker from being able to “listen in” on a single frequency intercepting all the message packets, since the packets are randomly being transmitted across a range of frequencies. Other security measures that are used include unique message network IDs, encrypting messages, and password protected access into the lighting control system.
DiLouie: What protocols are popular?
Crane: Popular protocols include Zigbee, Xbee, EnOcean, Bluetooth, Bluetooth LE (Low Energy), and SNAP (Synapse Network Appliance Protocol).
DiLouie: How are these systems typically set up and commissioned?
Crane: Typically the contractor will install an actuator either in or on a fixture or junction box. The hot will go to the actuator, neutral to both the actuator and the fixture, and the actuator’s switch leg will go to the hot on the fixture. Battery or energy harvesting input devices are typically mounted where they normally would be. Devices are then discovered and added to a network by a network programming device. Once added to the network, devices (e.g. a luminaire, an occupancy sensor and a switch station) are then grouped or bound together to create the control assignments.
DiLouie: How are these systems typically integrated with hardwired lighting and energy management systems?
Crane: Typical integration of wireless controls with hardwired lighting and energy management systems is done either using gateway devices that translate from one protocol to another or via wireless devices that support hardwired dry contact inputs and outputs.
DiLouie: What are the pitfalls with this technology? How are they addressed in application?
Crane: One of the challenges with wireless lighting controls is making sure that devices are within radio range of the other devices in the wireless network. If a device is out of range, then there exists the possibility that that device will never be able to communicate with the other devices. This is typically addressed in applications by having the wireless devices act as message repeaters and by adding additional wireless devices/repeaters to the network. This ensures that a message sent within the network can reach all the devices within the network.
DiLouie: If you could tell the entire electrical industry just one thing about RF wireless lighting controls, what would it be?
Crane: RF wireless lighting controls typically have a unique address associated with each device that is used to commission or program the device into the wireless lighting control system. This address is usually on a sticker attached to the product or on a set of stickers included with the product. It’s very important that these device addresses are saved and not thrown away so that they can be used to quickly commission the system. If the addresses are not available, commissioning the system will take more time.
DiLouie: Is there anything else you’d like to add about this topic?
Crane: RF wireless lighting controls are easy to implement, provide a lot of flexibility and are cost efficient. Good lighting control practices however still need to be implemented even when using wireless lighting controls. The correct application of occupancy sensors, photo-sensors and switch stations in an area will ensure a higher degree of customer satisfaction.