The best location for a presence sensor
Energy Efficiency
Team Legrand
11/07/2024
Team Legrand
11/07/2024
Presence sensor technology has become an essential component for optimizing energy efficiency and improving safety in a variety of environments, both residential and commercial. These sensors, which detect the movement of people, are essential for automating lighting systems. However, the effectiveness of these devices depends largely on their correct location, which varies according to the type of technology they employ. In this article, we will explore the different presence sensor technologies available and offer recommendations on where to place them to maximize their detection capability and functionality.
The location of a motion sensor is essential to ensure its correct operation. The type of sensor technology to be installed has a considerable influence on the place where it should be located so that the detection of the passage of people is optimal.
There are three types of motion or presence sensor technology:
1)Passive Infrared (PIR) Sensor
The PIR sensor detects occupancy through the difference between the heat emitted by the moving body and the ambient space.
2) Ultrasonic sensor
Ultrasonic detection works by transmitting ultrasonic sound waves over an area and measuring the frequency at which they return. The movement of the occupants changes the frequency at which the sound waves return.
Unlike PIR sensors, which only detect the movement of infrared heat sources (such as humans), ultrasonic sensors detect the movement of any object, whether or not it emits infrared heat.
3)Dual sensors : Dual sensing technology (PIR+US)
The dual technology sensor combines PIR and ultrasonic technology.
The sensors turn on the lights when both sensor technologies detect presence and maintain illumination over time, as long as one technology continues to detect.
WHAT DETECTION ZONES SHOULD A PRESENCE SENSOR HAVE?
The sensors can be characterized by 3 detection zones:
Transverse (or tangential) detection: when a person approaches the sensor at an angle.
Axial (or radial) detection: when a person approaches the sensor from the front.
Sitting position detection ; for small movements.
Axial detection is the one that best guarantees the detection of a sensor whatever the approach mode.
RECOMMENDATIONS FOR SENSOR LOCATION POINTS ACCORDING TO THEIR TECHNOLOGY TYPE
1) PIR Sensors
PIR sensors should be placed where there are no obstacles blocking the people who should trigger the sensor:
The PIR sensor must not be able to ''see'' outside the desired area:
The best detection can be achieved when a person crosses the coverage zones:
2) Ultrasonic sensors
Ultrasonic sensors can detect occupancy even though there may be obstacles between the sensor and the person moving:
(Unwanted) detection outside the controlled area should be avoided:
They should be located away from air currents, such as air conditioners and fans:
3)Dual technology sensors:
Dual technology sensors can detect occupancy by jumping over obstacles due to the intrinsic capability of ultrasound:
If occupancy is what will be determined first by both PIR and ultrasonic technologies simultaneously, the sensor should be located where it can "see" people and avoid open areas:
Mount them on a vibration-proof surface and away from air conditioning or heating sources:
As a summary of what has been explained about the location of the presence sensors, according to their type of technology, we can consider this table of recommendations:
