Home > Business > Total Perimeter Security System > Perimeter Intrusion Detection System   There are four main categories of sensors when it comes to PIDS (Perimeter Intrusion Detection System):   Field Sensors: This can include microwave, IR (Infrared), magnetic and others. Detection is usually done with a transmitter and receiver covering a volume of area. This creates an invisible area of detection. If an intruder enters this area, then the sensors detect the movement, radiation change, etc (depending on the sensor technology) and reports the intrusion by zone.   Vibration Sensors: The typical configuration for a vibration sensor is a single cable attached along the middle of a chain link fence. It detects vibrations on the fence, but has weaker detection along the top and bottom using this setup. More lines and/or elaborate configurations can be used to increase detection at the expensive of cost. Detection is often reported by a zone of 100m, but can vary depending on the amount of processors spaced along the perimeter.   Taut-wire Sensors: These are fences that contain anchoring posts and sensors spaced out at intervals. Lengths of taut-wire are strung between the posts in parallel, and any changes caused in the tension triggers a zone alarm. Typically not easy to install and requires frequent tension checks.   Fiber Optic Mesh: Usually a 2-D mesh of fiber optic cable attached to a fence or barrier. Pressure, cuts or bends in the fiber optic cable is detected by a controller which is sometimes installed along the fence at fixed intervals. This means that unlike the FOMGuard system, the sensors are exposed outdoors. Detection within 15-20m is typically achieved by other Fiber Optic Mesh systems.     IR / EM / Microwave Sensors Vibration Sensors Taut-Wire Sensors Other Fiber Optic Systems FOMGuard Detection Principal Motion, EM disturbances, radiation, etc. Vibrations in mounted barrier Force applied to taut-wires OTDR technology (Sometimes vibration based) OTDR technology Detection Range Zone detection, 100-300m Zone detection, varies by frequency of sensors Zone detection, 100-300m Located within 15-20m Pinpoint accuracy, within ±25cm Vulnerability to defeat (All are vulnerable to bridging or deep tunneling) ＊Extremely slow or fast crossing ＊Crawling ＊Crossing during rain/snow/winds ＊Silent cutting ＊Slow or fast cutting/climbing ＊Intrusion during strong winds ＊Balanced cutting ＊Taut-wire clamping ＊Sensor tampering ＊Tampering with cross buttons ＊Separating net bottom from fixtures ＊Detects all climbs, cuts and tampering under all conditions Environmental Effects ＊High false alarm rate during rain, storms, snow ＊Affected by EMI/RFI ＊Damaged by lightning ＊Small animals and other moving factors cause nuisance alarms ＊High false alarm rate during rain, storms, snow ＊Affected by EMI/RFI ＊Damaged by lightning ＊Nuisance alarms from small animals ＊Extreme temperature can change wire tension ＊Damaged by lightning ＊Some systems have outdoor sensors / electronics that can be damaged by weather ＊Not affected by weather effects including strong winds, extreme temperatures and lightning ＊Not affected by EMI/RFI Maintenance ＊Environment changes require sensor updates ＊Sensors require frequent maintenance checks ＊Environment changes require sensitivity updates ＊Sensors require frequent maintenance checks ＊Cuts in cable require total replacement ＊Tension /sensitivity needs adjustment with temperature and wind changes ＊High man-power required to install ＊Tensions need to be checked often ＊Does not report exact location of defect or cut ＊Mesh design requires a medium/large section to be replaced when cut ＊Reports exact location of defects/cut in net ＊Very small section replaced onsite to repair cuts ＊Does not require frequent maintenance checks Perimeter Requirements ＊Offers no physical barrier ＊Requires protection for the sensors ＊Requires a physical barrier to be mounted on ＊Does not fit to existing fence ＊Terrain conditions cannot be harsh or “hilly” ＊Requires a fence to be mounted on ＊Lacks options for solid barriers like brick walls ＊Lacks customization for gates, pipes, etc. ＊Mounts to any existing barrier or as a stand-alone ＊Solutions for walls, gates, or any perimeter obstacles
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