Craig DiLouie, LC recently interviewed Mike Crane, product manager for Hubbell Building Automation, for ELECTRICAL CONTRACTOR on the topic of wireless RF lighting control. The interview is published here in its raw form.
DiLouie Please describe what wireless RF lighting control is, how it works, and its intended purpose.
Crane: Wireless RF lighting control is the ability to turn lighting on/off and dim to a specific level remotely over the air using radio technology. Actuator devices, which contain relays for turning the lighting on and off, are wired directly to a fixture or lighting circuit. Input device, such as a switch, occupancy sensor or daylight sensor send commands over the air via radio signals to the actuator who then responds to the command accordingly. These commands typically tell the actuator to close or open its relay and if it does dimming, to what level the lighting should be set to.
DiLouie: How would you describe the history of wireless RF lighting control’s evolution over the past 10 years? Where did we start? What key changes occurred in the technology/market allowing progress? Where are we now? Where are we headed?
Crane: Wireless RF lighting controls primarily got its start in the residential market. 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. 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, 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 luminaries with wireless controls built in.
DiLouie: What are the benefits of wireless RF lighting control? What opportunities do these benefits create for electrical contractors?
Crane: Wireless RF 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 eliminate the need for expensive dedicated low voltage control communications wiring. Wireless lighting controls not only provide benefits to the end user, they also create an opportunity for the electrical contractor for commissioning services. Once wireless lighting controls are installed, they typically need to be programmed or commissioned. This involves the pairing of actuators with input devices. This programming is sometimes done physically on the device or via software. Electrical contractors who are knowledgeable in the various wireless lighting controls can expand upon their services by offering system commissioning.
DiLouie: What are the different approaches to wireless RF lighting control (fixed, mesh, etc.) and what are the pros and cons of each? What elements do most manufacturers share and where do they commonly diverge into different approaches?
Crane: The two most popular approaches are fixed-based and mesh-based systems. Fixed systems typically pair actuators directly to input devices. They are typically in close proximity to one another. Mesh-based systems also pair actuators with input devices and also support the ability to route and repeat messages throughout the network – ensuring that the originating node’s messages gets to the target node. By having each device be a repeater, mesh-based systems provide the ability to have a large network of devices. The pros and cons of each all depend on what the lighting application is. If all you need to do is control a single room with an actuator and a switch, then fixed based controls may be all that you need. If you want to change configurations over the air, or control lighting based on schedules, or control all the devices from a central location or remotely over the Internet, then a mesh-based system may be the appropriate solution. The pairing of actuators with input devices is the element that most manufacturers share since it’s required for both fixed and mesh based systems. Where they tend to diverge is on the type of approach – fixed or mesh. Hubbell Building Automation offers both mesh-based and fixed-based wireless control solutions for a variety of lighting applications.
DiLouie: What have been the biggest changes or advances in wireless RF lighting control over the past 2-3 years, and how has this influenced offerings and adoption of wireless control?
Crane: With the growth of wireless technology in general (e.g. cell phones, wireless home phones, wireless Wi-Fi routers), the cost of radio technology has now reached a point where it is affordable to manufacture wireless lighting control products and not destroy the overall return on investment of the luminaries with controls. Also, lighting unlike other building systems (e.g. HVAC) requires immediate response times. Users are okay with waiting 5-10 minutes for the heat to turn on after adjusting a thermostat, but will not wait for lighting to turn on or off after a light switch has been pressed. Improvements in the various wireless control protocols to address lighting’s requirement for quick response times has also been an influence in the ability to provide suitable offerings.
DiLouie: How are these systems installed and set up? What do contractors need to know?
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. If this is a fixed based system the contractor will typically put the actuator into a “learn” mode and then pair it to the switch by pressing the switch. For meshed-based systems the actuators are typically wired up the same way. Meshed-based input devices may be battery operated or powered via a power-pack. Software running on a laptop or PC is then used to communicate to an access point or gateway device which discovers and pairs devices.
DiLouie: Wireless lighting control networks appear to be covering bigger commercial applications than before. What lessons has the industry learned about applying wireless lighting control to large applications?
Crane: Wireless systems have to have devices that can repeat messages and route them via different paths. This ensures that messages will still get to their target destination, even if one or more paths may be unavailable for whatever reason (e.g. an inoperable node in a path). Another lesson learned is that large wireless lighting applications need a way to uniquely identify each device and addressing dip switches or knobs is definitely NOT the way to go. They are limited to the number of addresses they can support which in turn limits the number of luminaries and input devices supported. There are now wireless protocols that support unique addresses associated with each radio. This provides the ability to support large networks. As long as one device is in range of other devices, it can participate in the network…no matter what the size of the network is.
DiLouie: The most common protocols governing design of wireless RF lighting control products appear to be Zigbee, Z-Wave and EnOcean plus various proprietary protocols. What are the pros and cons of these approaches? What are ideal applications? Are there any other protocols of note?
Crane: Another protocol of note is SNAP (Synapse Network Appliance Protocol). Like Zigbee, the SNAP protocol provides the infrastructure to create peer-to-peer, self organizing and self healing mesh networks. The major difference between Zigbee and SNAP is that SNAP supports 900MHz radios while Zigbee supports 2.4GHz radios. The major difference being that for 900MHz provides almost twice the radio coverage and is least affected propagation losses due to penetration through obstacles, diffraction and reflection. The SNAP protocol also does not require a coordinator (potential single point of failure) like Zigbee does.
DiLouie: The ideal control solution for a given building may require a mix of wired and wireless lighting control solutions, and wireless lighting control integrated with other building control systems. What questions do designers need to ask to ensure that all components talk to each other properly? What’s needed?
Crane: Can this system communicate with other building control systems? If so, how is the integration accomplished? What building management system protocols are supported? Bacnet? Modbus? Lon? Does the system provide an input/output interface for other devices (e.g. motorized window shades)?
DiLouie: Integrated lighting control appears to have strong potential for LED lighting systems. Does wireless RF lighting control have any particularly suitability with LED lighting compared to wired control methods?
Crane: Yes. As the cost of energy continues to escalate, the value of indoor and outdoor lighting solutions which capitalize on both energy efficient LED lighting technologies and aggressive energy saving control strategies, continues to grow. For example, with solutions available from Hubbell Lighting today, outdoor LED lighting with integrated wireless control can be programmed over the air to dim down to a certain level at a specific time, and then dim even further throughout the evening – saving energy and reducing light pollution. If the lighting ever needs to be manually changed, a user can easily send a wireless command (via a wireless switch or through their Internet web browser) to the LED lighting to immediately adjust to a new level.
DiLouie: If you could tell all electrical contractors only one thing about the wireless RF lighting control, what would it be?
Crane: When working with mesh-based systems that have unique addresses for each device, it’s imperative that the address information provided with each device is not discarded, but properly recorded on site plans or as-builts. Having this information available is key to the successful commissioning of the system.
Special thanks for Mike Crane.