How Dali-based systems are assisting buildings to achieve smart optimum lighting control.
When decision-makers consider smart building technology in buildings one the first aspect that comes to front of mind is that of automatic lighting control. Good lighting is crucial to the successful functioning of any workplace and, also accounts for a large proportion of energy consumption.
Therefore, it is important to have intelligent and on-demand control of lighting in place. Among other things, this is facilitated using highly accurate multi-sensors which can enable building managers to control the artificial light depending on occupancy and brightness levels.
A DALI-based lighting control system can deliver exactly this, enabling consultants to first plan the optimal solution for the requirements of smart buildings. Typically, engineers then create CAD drawings with the lighting groups defined all in close consultation with the building’s facilities management.
Commissioning can be complex and for this stage, the system integrator will attend the site, supported by technical engineers. Here, they can then align the system and building and clearly define the necessary rules and user authorisations. This ensures that building managers can access precisely the most relevant part of the system for their needs.
Measuring brightness
To achieve the optimal function of the intelligent system in place, the measured brightness value needs to be extremely accurate. This is achieved by finding the best location on the ceiling for the installation, where measurement is influenced by as little as possible by external factors such as reflection, direct sunlight, or other light sources. Brightness values should be measured in the darkest part of the room, which may differ from room to room depending on its location in the building. However, the detection range of the unit must of course ensure adequate cover of the occupants’ range of mobility in the room.
For optimal lighting control, the difference between the brightness at the desk and the brightness at the ceiling must be balanced in the logic of the multi-sensor. Therefore, the actual value measured by the light sensor on the ceiling is not used for the control in order to supplement the natural light with the appropriate amount of artificial light. Instead, a so-called reflection factor is used as the ratio of light between the work surface and the ceiling.
With a DALI-based system, the weighting of the reflection value is set individually according to the environmental variables of the respective place of use.
Staff access
By means of a username and password, staff can be given access to areas in which they can influence the lighting control. They can log in via their browser and control the light in their room or office. Via a user-friendly interface, they can select scenes, switch and dims the light as appropriate.
In a specific meeting room or boardroom, for example, staff can also control the light via smartphone. These scenes are stored in the system for different meeting situations, which can be called up with a click.
System connection
The connection of this system to a higher-level building management system or to parallel existing systems for other trades such as heating, ventilation, blind control or access control can be easily realised via A BACnet router. Up to 712 nodes are provided per router via BACnet/IP, with the help of which lighting values, presence and status information can be read out. Multi-state objects allow different lighting control commands to be routed to the DALI system from a higher-level software.
In this way, the lighting control system can be overridden from a BACnet-based control centre, for example. Hidden functions such as the remote maintenance option or the software update of control devices via the DALI bus contribute to the very high operational reliability of a DALI-based system. Maintenance is facilitated by a quick system overview and automatic error notifications. Key figures such as the lighting duration of individual lamps or the energy consumption of the system can be viewed transparently at any time. A system administrator can monitor, configure and maintain the systems via PC or mobile devices. This is how user-friendly and environmentally friendly lighting.
To make buildings even ‘smarter’, high-tech wall sensors can also be added which measure both air quality and humidity based on the level of Volatile Organic Compounds (VOCs) or carbon dioxide (CO2) in the air while, also acting as a temperature controller.
VOCs are released into indoor air by natural emissions from human bodies, mostly through ventilation systems. High levels of CO2 can lead to individuals losing concentration, experiencing headaches or tidiness which can be problematic for workplaces or offices.
With the help of a built-in LED traffic light (with the colours green, yellow and red), these wall sensors warn by colour change as well as by an additional acoustic signal if the indoor air has reached a critical value. This means if the air quality is poor (and red), the air conditioning can be switched on or a window can be opened to improve air quality in the room.
Paul Jones is UK & Ireland Sales Director for B.E.G. UK Limited
