Occupancy sensors are also called motion sensors, which turn on or off lights based on factors such as heat or motion. When people are detected, the lights turn on and, if no people are spotted during a predetermined period, they turn off. Light energy consumption can be reduced by 35 to 45 % or more, depending on the site.
Types Of Occupancy Sensors And Its Placement Options
Occupancy sensors operate by sensing heat or changes in the ultrasonic reflectivity of sounds. The use of audio or microwave units is less common. The types of sensors are discussed below.
1. PIR Occupancy sensors
The most common type of sensor is a PIR sensor. They detect human heat energy through infrared. The sensor is triggered when the level of infrared changes, that is, when warm objects move out or in of the sensor's field of view. The PIR sensor is a passive device: it detects radiation only; it doesn’t emit it. It is designed to detect heat energy emitted by humans at a wavelength that is most sensitive to. The devices are strictly line of sight. If obstacles exist, it cannot detect through corners, and it will not detect. For example, if a physical barrier separates a person from the detector. There is risk of false triggering with PIR sensors.
PIR sensors detect hand movement at approximately 10 feet, arm and upper-body movement at approximately 20 feet, and the entire body movement at about 40 feet. There can be big variations in sensitivity, depending on circuit design and product quality.
2. Ultrasonic sensors
An ultrasonic sensor emits a high-frequency sound, beyond the audible range of humans and animals, and listens to the reflected noise. Unlike PIR sensors, they cover a larger volume and are significantly more sensitive, but they are also susceptible to false triggers. Air movement from a person walking through a doorway, or switching off and on a HVAC system, can trigger poorly adjusted sensors. Throughout the targeted area, ultrasonic waves are continuously applied, the application pattern does not have any blind spots. As a result, ultrasonic sensors can detect movement more easily.
3. Dual-technology or hybrid sensors
A sensor with both US and PIR capabilities, or another sensor, like a microwave. Generally, PIR and ultrasonic sensor types are combined, since PIR sensors are resistant to false triggers and ultrasound sensors are more sensitive.
Occupancy Sensors Placement Options
Occupancy sensors can be mounted in two basic ways. A ceiling-mounted sensor has independent control and power supply. These types of sensors can be wall-mounted or positioned in corners, or even on ceilings. The Wallbox sensor is designed to replace conventional wall switches. You can choose either ultrasonic or PIR sensing units for ceiling-mounted or wall box sensors.
How To Mount Occupancy Sensors
Tools Needed for mounting occupancy sensors
- Wire caps
- Switchplate cover for occupancy sensor
- Occupancy sensor
Step 01: Turn off the power
Disconnect the power to the outlet where the sensor will be installed. Make sure the power is off by switching it on and off.
Step 02: Remove the switchplate
Remove the switchplate cover, using a screwdriver. Once the switch plate has been unscrewed, disconnect it. Take the wires out one by one, being careful of the existing wiring.
Step 03: Connect the sensor
Input the occupancy sensor into the outlet, one by one. The ground wire in the outlet is connected to the green and bare copper wires from the switchplate. A black wire from the switch plate is connected to a black wire to the outlet. If there are any wires remaining, they should be capped. Be sure to review the instructions provided by the manufacturer before installing your sensor, especially if your switch has multiple circuits. Perhaps you need to make some changes to the wiring.
Step 4: Screw the sensor in
Put the capped wires back in the wall after they have all been connected. Use a screwdriver to attach the sensor switchplate. Alternatively, screw the cover to the sensor switchplate. Put the power back on the circuit breaker.
What are the steps to adjust an occupancy detection light switch?
In factory settings, the maximum light level is set, so that even bright light won't interfere with the sensor turning on a load when the sensor detects occupants. Unless you need this feature, turn the light up as far as possible clockwise. When the lights are normally turned off, the lighting level needs to be adjusted since there is enough natural light. For each RW3U600, the light level may be different.
- Turn all RW3U600s Manual ON, except for the one you wish to adjust. If you are adjusting the RW3U600 occupancy sensor, turn it to Mode 2 Automatic ON.
- Reducing the delay time to 15 seconds.
- The light level should be adjusted to the lowest possible setting (completely counterclockwise) for the unit you are adjusting. You must leave the area of coverage. Make sure the sensor is timed out, so lights should be OFF, and wait another 30 seconds.
- Ensure that you do not cast shadows over the sensor by entering the area. Turn the lights off. Make small adjustments to the Light Level trimpot. Each time you adjust, watch for the lights to illuminate for five to ten seconds. Continue this process until the lights are turned on. As long as the light level measured at this sensor is higher than the natural illumination, the light will not turn on automatically with occupancy.
- Then, repeat the procedure (starting at step 1) with each RW3U600 in the multiway configuration until all Light Levels are adjusted correctly.
- After all, RW3U600s have been adjusted to the Light level, switch them all back to mode2.
- All units should be reset to desired time delay.
The use of occupancy sensors has become important for the control of HVAC systems of buildings as thermostats were once. By regulating and controlling ventilation on-demand, they provide more comfortable working and living environments, along with sustainable environments. Based on how a building is used on a daily basis, occupancy sensors play an important role in reducing building energy consumption.