Sensor for room lighting control

In different types of lighting systems, lighting can be controlled based on different variables to achieve not only energy savings but also changes in the desired functionality or atmosphere of the space. Lighting can be controlled manually or with intelligent control systems that can save up to 70% of electricity by controlling (dimming) the lighting or automatically adjusting the lighting according to the user's requirements.

Lighting control is mainly based on:

Daylighting

The lighting system often operates at full power when there is sufficient daylight. By means of sensors that react to the light level in the respective space, artificial lighting can be dimmed when daylight increases so that the desired illuminance value is maintained. In this way, the artificial light can be dimmed until it is switched off in sufficient daylight. The electricity savings achieved can be up to 35% depending on the location, orientation of the space and the time of year.

Presence of persons

According to renowned research, it is estimated that interior lighting systems are in operation for about 20% longer than necessary due to the momentary absence of people in the illuminated space. By using sensors that react to the movement of people, the light output of the lighting system can be reduced or switched off completely in the absence of people.

Age of the lighting system

As light sources age and their luminous flux decreases during their lifetime, a so-called maintenance factor of typically 0.6 to 0.8 is used in lighting design. This means that in a lighting system with new sources, or after regular maintenance at a maintenance factor of 0.7, the initial illuminance level is 30 % higher. Once the light source has reached the end of its economic life, the illuminance level will equal the design level. By maintaining a constant illuminance level throughout its lifetime, approximately 10 % of electricity can be saved. New requirements of the layout of the premises and their occupants.

Personal settings

Users of different indoor spaces have their individual needs for the quality and quantity of lighting during their activities. The personal comfort of the users allows them to set a comfortable control of the lighting system. The comfort associated with the quality of lighting system control is achieved by the use of sensors and remote controls.or control buttons connected to the lighting system control unit.

Space atmospheres

By varying the lighting intensity or chromaticity temperature during the operating cycle in rooms such as offices or classrooms in schools, the workload of staff or the activity of pupils in the learning process can be effectively promoted in accordance with the biorhythm of the human body. With the advent of new technologies such as LED or control systems for coloured fluorescent lamps, the atmosphere of a room can be changed. The headmaster's office can become, for example, a fun space full of colour and emotion after a successful acquisition of a new company.

Modern control systems increase the comfort of the lighting system and bring significant savings in energy consumption and lighting quality in the illuminated space. The present is characterised by the digitisation and
addressing of the individual functional elements of the lighting system (luminaires, light sources, control units, extension sensors, etc.). The digital control protocol DALI can be considered as an important step in the introduction of control.
Intelligent control systems use light sensors to automatically control artificial lighting. Light sensors sense the intensity of the lighting in a room. The control system processes the information and adjusts the amount of control. Light sensors mainly use photodiodes or phototransistors to sense the light intensity. Some types of sensors can directly control dimmable electronic
ballasts, whereby the illuminance reference is set directly on the sensor. The sensor is powered directly from the ballasts or from the control units.
In the following, these control systems from the Philips OEM portfolio are presented in more detail with regard to functionality, technical parameters and application areas:
- Luxsense
- Occuswitch
- Actilum
- Occuplus
- Actilum color
- ToBeTouched