The Duplex motion detector sensor is a passive infrared motion sensor (PIR motion sensor) with two PIR sensors. It reacts to all types of heat movement and reports this to the alarm center. The two PIR elements ensure a high level of protection against false alarms. The reason: An alarm is not triggered until both sensors register movement. The best place to install the sensor is in a corner, between 2 and 3 metres above the floor. The intruder's possible direction of movement should be at right-angles to the sensor. Do not install the motion sensor near to electric cables, gas lines, or electronic equipment that generate heat during long periods of operation. The viewing angle of the Duplex motion detector sensor is 90 degrees, and the detection range – depending on installation height – up to 15 x 15 meters. You can vary its sensitivity by means of a jumper. In this way, you can define the number of pulses that have to be detected before the sensor opens the alarm relay. The Duplex motion detector sensor has an alarm memory. If the alarm center is disarmed following an alarm, the LED on the sensor that triggered the alarm lights up. Depending on the configuration, you can also see which sensor first triggered the alarm. On this sensor, the LED flashes.