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Perimeter guard against infrared detector installation must look

Jun 15, 2017

The general installation of dual-beam active intrusion detector requires the detector under the beam from the top of the wall around 150mm, so as to ensure that the intruder in the wall will just cover the two infrared beam, and trigger alarm.

However, the two-beam detector (compared with the single beam) will not cause false positives due to the occlusion of a light beam, such as small animals, leaves, and so on to a certain extent improve the detector's * and stability.

Therefore, it is reasonable to choose the dual-beam detector in the general outdoor application situation considering the factors such as the availability, stability and economy.

In addition, the long distance detectors generally require the use of nominal value ≤ 100 meters (by the detection distance of 70 meters), so that the detection zone is always ≤ 70 meters, making it conducive to alarm positioning.

Installation Location Requirements

The response time of active IR intrusion detectors should be paid special attention in installation and use. In accordance with national standards (GB10408.4. -2000), when the beam of the general detector is obscured by the duration ≥ (40) MS, the detector shall generate an alarm signal; The beam is blocked for a duration ≤ (20 10) MS, the detector should not generate an alarm signal. This shows that (20 10) Ms when the occlusion time (40) MS, there is an alarm or not the uncertain time domain. Occlusion time is determined by the movement speed of the occlusion object and its occlusion volume. So in order to avoid (20 10) MS (40) MS (the uncertain time domain of alarm or not), the general requirements of the perimeter detector installed on the top or slightly outside the wall, because the speed of climbing is much lower than the speed of the jump, so on the climb time is more than the next jump time (people jumping, occlusion time may be less than 20ms) to delay occlusion time. As shown in Figure 4, A and B installation position is reasonable, and C position is never recommended.
 In addition, the cross-section size of the person is also the active infrared intrusion detector installation to consider the basis. For example, in reference to the Shanghai Local Standard (DB31 2003) requirements, such as installed at the top of the wall (b position), the required beam distance from the top of the fence (150) mm; According to the above-mentioned spacing generally can ensure that intruders in wall can effectively block the double beam, and the normal triggering alarm.

Avoid Blind zone requirements

Two pairs of adjacent active infrared intrusion detectors require delivery * installation, the general requirements of the spacing to be S. 300 mm, that is, at least within the MM is two of the adjacent detectors of public protected areas. Of course two pairs of adjacent detector beam direction to the opposite.

If the column and fence-shaped wall, general two pillars of the spacing far greater than the MM, and in the 3, at this time to protect the column is the most ideal choice.

Other installation Requirements

Should pay attention to the perimeter detector installation and perimeter entities, greening and other reasonable coordination, if not coordinated beforehand, easily out of the dead corners and loopholes, resulting in the perimeter guard equipment can not be properly installed, resulting in no detection effect. For example, some communities to beautify the column is very high, the column lamp too large, the top of the fence wave-type or from the top of the column too far away, the thick branches of the detector rays and so on, will greatly affect the effect of the perimeter detector.

The two pairs of active IR intrusion detectors mounted on the same line should be installed on the transmitter or receiver. Otherwise, a transmitter of the detector will be injected into the receiver of another pair of detectors, and the probe may not function properly.

Therefore, the actual installation, the use of the same line of two pairs of active IR intrusion detectors should be launched or received end back, or the use of frequency modulation function of detectors, can also avoid the transmission of interference with each other.

Multiple cross-dimensional prevention example

In the museum and other important parts are often used for active infrared detectors and a variety of other technology detectors, such as pressure detectors, vibration detectors, glass broken detectors, light cover, etc., together to form a multiple-dimensional prevention system. Many pairs of active IR intrusion detectors and pressure detectors are used to form the three-dimensional protection, and some also use television camera monitoring technology and sound composite technology to create multiple stereo protection. Of course, the measures are also indispensable, it is to extend the time to prevent criminals, to stop the crime and capture the criminals to win ample time.

The Active IR intrusion detector is widely used in recent years because of its stable performance, convenient installation and low price. In order to use the anti-theft equipment, should understand its technical performance and installation points, in the practical application of the advantages and disadvantages, for my use, so that it can play the best effect.