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Đăng lúc: Thứ bảy - 03/05/2008 10:45

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Security System

Security System

Security System

If you really want to do everything you can to safeguard your home or business, the security systems from Ademco, Caddx, Nappco, Sentrol, are the smartest move you can make. You'll feel safe and secure, knowing these advanced systems are constantly on the lookout for any sign of trouble.

Security System


If you really want to do everything you can to safeguard your home or business, the security systems from Ademco, Caddx, Nappco, Sentrol, are the smartest move you can make. You'll feel safe and secure, knowing these advanced systems are constantly on the lookout for any sign of trouble.



 


Infrared Motion detection is a passive system that detects infrared energy.


 



 


These sensors are therefore known as PIR (passive infrared) detectors or pyro-electric sensors. In order to make a sensor that can detect a human being, you need to make the sensor sensitive to the temperature of a human body. Humans, having a skin temperature of about 93 degrees F, radiate infrared energy with a wavelength between 9 and 10 micrometers. Therefore, the sensors are typically sensitive in the range of 8 to 12 micrometers.


Motion detectors are sensitive to motion, but not to a person who is standing still. That's because the electronics package attached to the sensor is looking for a fairly rapid change in the amount of infrared energy it is seeing. When a person walks by, the amount of infrared energy in the field of view changes rapidly and is easily detected. You do not want the sensor detecting slower changes, like the sidewalk cooling off at night.


Motion Photoelectric Beam Detectors -



If you've ever walked into a store and heard a bell go off as you crossed the threshold, chances are it was caused by a photoelectric detector. Behind the door on one side of the store is a light (either a white light and a lens or a low-power laser), and on the other side is a photodetector that can "see" the light. When you cross the beam of light, you break the beam. The photodetector senses the lack of light and triggers an alarm.


 


Microwave Detectors - Many grocery stores have automatic door openers that use a very simple form of radar to detect when someone passes near the door. The box above the door sends out a burst of microwave radio energy and waits for the reflected energy to bounce back. When a person moves into the field of microwave energy, it changes the amount of reflected energy or the time it takes for the reflection to arrive, and the box opens the door. Since these devices use radar, they often set off radar detectors.


 


Glass Break Detector



A glass break detector detects the breaking of glass windows and triggers an alarm. A dual technology detection method (air pressure and sound analysis) is used. Used processing guarantees high sensitivity to the breaking of all types of glass. The sensitivity can be adjusted to compensate for various window sizes and mounting distances.


Nguồn tin: T-M J.S.C
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