Passive Infrared (PIR) technology and reasons for false detection

Reason for false detection or missing detection can be several.
MTN630719, MTN630819 and MTN630919 are based on PIR (passive infra-red) technology. It means that the device is "measuring" heat sources and indicates presence when there is change in that measurement.
In the inner circle (~ diameter of 4m) small movements are detected, in the outer circle only larger movements are detected.
When movement is detected, the light nevertheless is only switched ON when the measured brightness is below threshold.
Very important is the mounting location of the product. If the sensor is mounted in the back of a person movements of the hand cannot be detected (even in the inner circle) as the sensor does not see the hand of the person because the hand is hidden by the back.
The detection is best at a mounting height of 2.5 meters. Larger heights will increase the detection area but decrease the sensitivity of the detector.
Temperature in the room can have an influence on the detection. If the room temperature is close to the surface temperature of a human body the detector will not see any difference between the air and the person and thus will not detect movement.
On the other hand, the flow of warm or cold air can be interpreted as movement as this is seen by the sensor as a change of emitted heat.
Some lamps are creating heat. When switching off the light this heat will disappear. Due to that the detector may interpret this as a change of heat emission and due to that will switch ON the light. To avoid this switching off we have communication object and parameter in the application software called "safety pause".

Released for: Schneider Electric Philippines