As published by Consulting-Specifying Engineer
The lighting controls are an integral part of any lighting system design and with all the components that impact system selection, it can seem intimidating. It doesn’t have to be.
Once you understand the lighting system design intent and basic architecture of the main lighting control system types, designing any lighting control system can be a relatively straightforward process.
Lighting control system considerations
The first step to designing a lighting control system is understanding the lighting design intent. There are three main categories to consider when designing a lighting control system: codes and standards, operations and maintenance and installation.
Codes and standards are first and foremost. There are really three types: codes, standards and owner preferences.
National and local energy codes dictate the minimum level of lighting controls required for both commercial and residential projects. Energy code requirements can include automatic shut-off, dimming, daylighting, demand response and manual controls, among others. These are incredibly important to understand early on in a project, because not meeting these requirements could cause issues during the permitting process or inspections and it could even delay receiving the coveted certificate of occupancy.
Sustainability standards or goals such as U.S. Green Building Council LEED or WELL building, if pursued, can add control requirements to the baseline such as additional dimming, daylighting or manual control.
After reviewing codes and standards, we need to consider how the owner would like the system to function, both now and in the future. Below are a few questions to ask:
Last, we need to consider how the system will both be installed and maintained. Specific site restrictions could direct the lighting controls toward one system type or another due to accessibility and feasibility. Here are a few considerations:
Once the above is understood, it’s time to look at the light fixture selections. Many may think light fixture selections and lighting control selections are two independent items. There are various dimming technologies, however and they are not interchangeable. This makes it essential to select lighting controls equipment that will properly control the selected light fixtures and vice versa. Additionally, if the fixture is also being used for emergency purposes via an inverter or generator, special considerations will be required for both the fixture and the controls.
Lighting control system architecture
Now that we’ve discussed important considerations regarding the lighting design intent, let’s discuss the basic architecture of the main lighting control system types available. This includes line-voltage, low-voltage, addressable and panel-based. Before we jump into details, we should all get on the same page regarding verbiage:
Line-voltage lighting controls are not used in commercial projects as much as they used to be due to modern energy codes, but they still have their place. The most common types include the standard wall switch (like we use in our homes), wall occupancy sensor switches and wall box dimmers. These systems offer limited control options and are truly standalone solutions.
Low-voltage lighting controls have a much wider range of use than line-voltage. While some of the technicalities of these systems can vary (e.g., power pack versus room controller, analog versus digital, wired versus wireless, etc.), the general architecture is similar. Most low-voltage systems have a power component that then connects to manual control devices and sensors via twisted-pair wires, category cable or a wireless protocol. These power components must be accessible and are often located above accessible ceilings in the same room or space as the loads they control. Low-voltage systems can often be either standalone or networkable.
When low-voltage systems are wireless, one component receives line-voltage power (usually a power pack or wall switch) and the others are battery operated (sensors or wall switches). When the switch is the component that receives line-voltage power, there generally isn’t an additional power component (such as power pack or room controller). It’s also important to remember that all components of any low-voltage lighting controls system must be by the same manufacturer and of the same communication technicalities to function. For example, a momentary light switch from manufacturer X won’t work with a wireless power pack from manufacturer Y.
Addressable lighting controls are when each individual light fixture has its own “brains.” In these systems, the light fixtures have specialized drivers or ballasts that all connect on a communications bus routed back to a central processor. The tricky part to addressable lighting control systems is that the required parts are spread out between the lighting controls package and the light fixture package.
Power over Ethernet lighting controls is the new kid on the block. They can generally be categorized as an addressable system, with the distinguishing component being the network switch. PoE lighting control systems require special light fixtures and devices that are all powered over ethernet cabling and connect back to a centralized network switch. Only a few manufacturers offer PoE solutions right now and if emergency lighting is being powered by a generator or inverter there are still a lot of questions regarding appropriate UL listings for the various components.
Panel-based lighting controls are often referred to as a centralized solution. These require the homeruns from all controlled loads to be routed through the control panel. Devices such as switches and sensors are often daisy-chained together with low-voltage cabling and also homerun back to the control panel or centralized processor.
When thinking of the four main architectures listed above, it’s also helpful to know that a design isn’t limited to just one. Often projects will have at least two or more of the above systems. For example, a project might use line-voltage occupancy sensor wall switch for restroom lights, low-voltage room controllers for office space ceiling lights, task lights and receptacles, a centralized panel for common corridors and a retail space with gypsum ceilings and addressable drivers for light fixtures in a flex space.
Networked lighting control systems
Most of the lighting control system architectures discussed above are capable of being networked. The main feature most commonly associated with networked systems is time clock functionality; all networked systems have a basic capability to schedule lights to turn on and off based on a schedule. Most of these systems contain astronomic time clocks, meaning the on and off operations can also be set to sunrise and sunset based on the project’s location. However networked lighting control systems can offer so many more benefits to owners and end-users.
One of the biggest perks of networking a lighting control system is having a single user interface to control multiple spaces or facilities. These user interfaces can range from a wall switch with touch-screen controls, an app on a tablet or other mobile device, specialized software on a computer or a dedicated website. Manufacturers often offer a range of options over this spectrum. An owner of one building may be comfortable with a standard app, while an owner of numerous facilities across the nation (or world) may want a website to access programming and statistics on any of their systems from one location.
There are also ranges of networking regarding the light fixtures themselves. In addition to adjusting time schedules, networking low-voltage and panel-based lighting control systems often provide the ability to adjust programming for digital keypads, dimming thresholds and sensor settings. The overall control zoning of these systems is wiring based, which means that if an owner wants to change how light fixtures are grouped together an electrician would need to adjust the wiring.
Networking provides additional benefits for addressable lighting control systems. Since each light fixture has its own address, owners can adjust the control zoning simply from programming (no electrician required). Each light fixture can also report its status, so maintenance can know when a driver is nearing end of life or if there is a malfunction. These individual light fixture reports can help owners strategically maintain their lighting control systems.
Finally, networking allows for enhanced integration with other systems. Integration can mean many things. At the most basic, it can be a contact closure that tells the system to do something. The most frequently integrated systems are security and fire alarm, as a simple contact closure from these systems can tell all lights in the system to turn on. Certain types of mechanical equipment can also be connected to lighting controls to receive an occupied/unoccupied signal which limits equipment runtime. At the other end of the spectrum, a single user interface can be used to control and program multiple systems. An example might be using a single touch screen to control the lighting, motorized shades and audio system in a room. Connecting the lighting controls to a full building automation system expands into fully controlling the mechanical systems as well. Another example may be to pull a timeclock or occupancy schedule directly from the BAS.
Systems commonly integrated or interfaced with the lighting controls are:
Selection and design
There’s bound to be a solution for every project given the wide variety of lighting control system manufacturers and options available. As technologies continue to change and develop at lightning speed and lighting controls become more data driven, it’s also imperative to think ahead to the future. This is especially important for projects and buildings with long life spans. Carefully designing a lighting control system increases the life cycle of the system and equipment, which is good for both the owner’s pocketbook and for sustainability.
Designing lighting control systems can be a daunting task, but when armed with the proper knowledge as outlined above, it does not have to be an intimidating process. With the variety of systems available, it is critical to select and design the proper system for each specific application.
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