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The working of combined acoustic PIR detectors is based on combined use of acoustic and passive infra red sensors. These sensors fitted in an enclosure, combine two intrusion detection techniques with individually adjustable sensors to suit both the environment and level of required security.
The acoustic sensor used to detect breaking glass has an independent LED.
The PIR is capable of covering larger area, approximately in the region of 10-12 rn.
The detection method used by these sensors ensures exact spotting of break-glass condition. This is because these sensors operate independently and each sensor has an individual alarm relay output.
Alternatively, for confirmed detection, if acoustic detection is followed by PIR detection.
Thus the digital logic in the detector can monitor both devices signals and generate an alarm signal if reqiured. This would apply where the requirement is for the break-glass condition to be verified as entry by the PIR detection. These combined type detectors can thus satisfy both perimeter and space protection needs by the installation of one unit only.
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