PATRICK DURAND said that open standards-based lighting control can address lighting OEMs' concerns about system complexity and scalability, interoperability of luminaires and control components, and flexibility in indoor commercial lighting applications.

When lighting OEMs bid for a project, they are often required to include a compatible lighting control system (usually from a third-party lighting control supplier) in the proposal, where the control system requirements are specifically assigned to the lighting OEM. To date, many lighting OEMs have responded passively to these requirements without developing a formal proactive strategy for lighting control.

Should we wait for a set of global lighting control standards?

The main reason for the failure to actively implement lighting control strategies is confusion, confusion about which technology to employ, and confusion about which supplier to invest in, especially for lighting control systems in indoor commercial and office environments. Most lighting OEMs do not have the time, resources or expertise to evaluate the benefits of all lighting control technologies.

For residential lighting control (ie smart bulbs), the mainstream agreement is clear, ZigBee Light Link is the winner in this regard, and multiple lighting OEMs support the agreement. However, for indoor commercial and office lighting control, technology choices are still changing (Figure 1) and the number is growing. Many lighting OEMs are choosing to wait for a dominant or de facto standard to avoid choosing the right technology at an early stage.

Figure 1. There are many lighting control technology options, which can be confusing for OEMs who require a compatible control system.

There are three main reasons for the lack of a dominant global standard. The first reason is that the main lighting control technology and/or the main LED driver dimming signal varies by region. For example, 0-10V is the primary LED driver dimming signal in North America, while DALI (Digital Addressable Lighting Interface) and Pulse Width Modulation (PWM) dominate in Europe and Japan, respectively. From the perspective of building automation systems, although BACnet seems to be a dominant global agreement, KNX is very popular in Europe. Therefore, it is difficult for lighting OEMs to rely on a single technology in order to adapt to end customers in various regions.

The second reason is that lighting control equipment varies with complexity. On the one hand, some devices simply require an inductive sensor to provide a signal to the LED driver depending on whether someone is in the room, and decide whether to turn it on or off. If there are multiple devices in different rooms throughout the building, and no gateway connects them to a centralized control system, these simple systems will operate independently. On the other hand, there is now a centralized lighting control system that manages, monitors and controls the lighting of buildings, even entire cities, entire countries, or multiple buildings around the world. The types of technologies that are commonly used to make these simple and complex systems tend to be significantly different. Therefore, this is another challenge for OEMs that rely on a single lighting control technology.

The third and most influential reason is that lighting OEMs do not specify lighting control technology for any given project. This is the responsibility of the decision maker, architect, building owner or building manager.

With these challenges in mind, what should lighting OEMs do when choosing lighting control technology to develop active lighting control strategies? The answer for many lighting OEMs is wait, because standards and complexity are yet to be determined. The reality is that there are many options, and depending on the application, certain criteria can be evaluated to determine the best solution to achieve and ultimately win the order. The choice of lighting control technology is based on five criteria: flexibility, interoperability, simplicity, scalability, and proven technology.

Flexibility and interoperability

All lighting control technologies fall into one of two major technology categories: patented technology or open technology. Products from specific suppliers using proprietary technology can only be used with other products from the same supplier. Lighting control companies that develop patented technologies have followed this business model because of their technology-driven value proposition or because of their strong market channels (especially for mature companies). Patented technology can be applied to specific lighting control projects with good technical adaptability, or patented technology is directly designated as a lighting control solution.

In contrast, open technologies are based on open or public standards, allowing multiple companies to develop products that use the same basic protocol; products from different vendors can interoperate as systems work (Figure 2). As a result, open technology gives lighting OEMs the flexibility to choose between multiple suppliers, mixing and matching solutions based on function, form factor and pricing to meet end-customer lighting control requirements.

Figure 2. Open standards for lighting control can combine different products and building systems designed by multiple suppliers using the same protocol.

There are two main open technologies for lighting control in indoor commercial and office environments: EnOcean and ZigBee. EnOcean is the first and only ISO/IEC wireless standard (14543-3-10) optimized for ultra-low power and energy harvesting solutions. As a result, lighting OEMs using EnOcean technology can benefit from wireless switches and sensors without the need for power and batteries. The EnOcean mechanical energy acquisition module converts mechanical energy (such as the mechanical energy of a finger-pressed switch) into electrical energy, which is supplied to the module for use in products such as wireless passive switches. The EnOcean Alliance currently has more than 350 members from around the world with more than 1,300 interoperable products.

ZigBee is based on the IEEE 802.15.4 standard, 802.15.4 defines the physical layer and the MAC layer, and ZigBee defines the network layer and the application layer. All ZigBee-based or 802.15.4-based lighting control vendors (except one) will customize ZigBee or develop a proprietary 802.15.4-based protocol. This is due to the inherent complexity of ZigBee in indoor commercial and office lighting environments. In fact, ZigBee is more like a patent agreement, because most lighting control products that use ZigBee or 802.15.4 are not interoperable between vendors. The only exception is a vendor that incorporates the additional intelligence required by ZigBee into its gateway. As a result, non-customized ZigBee endpoint nodes (switches, controllers, sensors) from different vendors can interoperate with the vendor's gateway, but this limits the choice of lighting OEMs for gateway vendors.

Figure 3 shows the various options that architects, building owners, or building managers specify from the perspective of dimming control, standard communications, and building automation systems (BAS). For example, a given project may require the lighting control system to support BACnet BAS with occupancy and daylighting sensors, where the fixtures must be controlled by DALI signals. Alternatively, the specification indicates that the lighting control system must be controlled and monitored via a smartphone and tablet, where the luminaire is controlled by a 0-10V signal. If the technology or supplier chosen by the lighting OEM is not flexible enough, the lighting OEM will eventually be forced to use multiple technologies from multiple vendors. This puts pressure on resources, especially the sales and sales representative teams of lighting OEMs who must deliver lighting and control solutions to end customers.

Figure 3. In an open technology-based system, the flexibility of lighting control can be achieved using existing interoperable components.

Simplicity and scalability

Some end customers, such as building owners and building managers, do not want to incorporate a BAS or centralized lighting control system that can be controlled, set up and monitored by a computer or mobile device. Instead, these end customers prefer to limit lighting control solutions to LED driver switches, sensors and controllers (typically 0-10V relays and DALI controllers) without the need for gateways or complex network equipment. In other words, these end customers want to provide a simple, independent lighting control system in every room in each building.

Currently, there are two main options for a simple independent lighting control system: the first is from a well-established proprietary lighting control supplier and the other is EnOcean technology. In contrast, currently available ZigBee or 802.15.4 based lighting control systems require the use of gateways or network devices. With a stand-alone system, the operation can be as simple as pressing a button on the wireless switch, like pressing a button on the wireless controller. There are also some operating options with a wireless USB dongle for some lighting control systems with PC software to fine tune certain wireless devices (ie sensors and controllers) settings.

Assume that, months or years after installing a simple stand-alone lighting control system, the building owner or manager decides to use BAS, or wants to use a PC/smartphone/tablet for centralized lighting control, setup and monitoring. EnOcean technology seamlessly and easily converts from a simple stand-alone system to a scalable network system without the need to change existing lighting control systems (Figure 4). ZigBee-based and 802.15.4-based lighting control systems can be extended to a complete building or even multiple buildings, but gateways or network equipment are always required at the starting point.

Figure 4. In this example, EnOcean supports a simple, scalable lighting control system with a single technology.

Proven control technology and support

Building owners and building managers often do not want their buildings to be a testing ground for emerging technologies. Therefore, the lighting control technology that lighting OEMs promote for the project must be a mature technology.

Leading ZigBee and 802.15.4 lighting control suppliers each have a user base of hundreds to thousands of buildings. According to the EnOcean Alliance, EnOcean technology has been installed in more than 350,000 buildings around the world.

Although ZigBee and 802.15.4 technologies are very reliable and have been proven in real-world scenarios, the availability of EnOcean technology in the international market may increase the chances that lighting OEMs will continue to win projects in different parts of the world. As a result, as more and more lighting OEMs sell their fixtures in multiple markets, lighting OEMs do not have to understand and promote different technologies based on the location of the project.

Source：LEDinside