Infrared detector is a method that detects the infrared radiation emitted by the human body, and then collects the infrared radiation from the outside world to focus on the infrared sensor. In this way, the infrared sensor uses a pyroelectric element. When this element receives a change in the temperature of the infrared radiation, it will release its charge to the outside, and detect a series of alarms that generate an alarm after processing.
So how does such an infrared detector operate?
(1) Adjusting the optical axis of the light projector Open the cover of the probe, point the eye at the sight, and observe the effects in the sight. The optical lens of the probe can be adjusted by hand directly to the left and right within 180 °. Adjust the screws. The lens system has an adjustment range of up to 12 °. Repeatedly adjust the impact of the counterpart detector in the sight to the central position. Be careful not to cover the optical axis during the adjustment process, so as not to affect the adjustment work. The adjustment of the optical axis of the projector has a great impact on the sensitivity performance of the zone. Please be sure to carefully and repeatedly adjust it according to the correct steps.
(II) Adjusting the optical axis of the receiver The first step: make preliminary adjustments to the optical axis of the receiver in the same way as the optical axis of the projector. At this time, the red warning indicator on the receiver is off, the green indicator is on, and there is no flicker.
Step 2: There are two small holes on the receiver, which are marked with + and-respectively. They are used to test the intensity of the infrared light felt by the receiver. The value is expressed by the voltage, which is called the photosensitive voltage. Insert the test leads (red +, black-) of the multimeter into the photoreceptor voltage of the photoreceptor. Repeatedly adjust the lens system to achieve the maximum photovoltage. In this way, the working state of the probe is optimal.
Note: The four-beam detector has two sets of optical systems, which need to cover the upper and lower lenses of the receiver separately and adjust until the upper and lower photosensitive voltages are consistent. The two optical systems of the older four-beam detector are adjusted separately. Due to the corresponding relationship between the four optical systems of the two probes of the transmitter and the receiver, it is very difficult to adjust. It needs to be adjusted carefully. False positives or dead zone protection. The ABF four-beam detector has integrated two parts into one body for adjustment, which makes engineering construction much easier.
(III) Shading time adjustment There is a shading time adjustment button on the receiver. Generally, the shading time of the probe is adjustable between 50m / s ~ 500m / s. When the probe is delivered, the shading time of the probe is adjusted to a standard in the factory. In terms of position, under normal circumstances, this position is a relatively moderate state, taking into account the environmental conditions and the characteristics of the probe itself, so there is no special reason, and there is no need to adjust the shading time. If it is necessary to adjust the shading time due to fortification reasons, to adapt to changes in the environment. Generally speaking, the shorter the shading time, the faster the sensitivity of the probe, but the sensitivity to falling leaves, flying birds, etc. is also strong, increasing the possibility of false alarms. Long shading time reduces the sensitivity of the probe and increases the possibility of false negatives. The engineer should adjust the shading time according to the actual needs of the fortification.
(4) After setting the connection probe with the anti-theft host, connect the tamper switch to the input circuit of the defense zone. After the connection is completed, cover the housing of the probe and tighten the fastening screws. It is required that the warning light of this zone on the anti-theft main unit is not flashing or lit, and no warning indication output is provided in the zone. Indicates that the entire zone is set normally. Otherwise, check the line, re-adjust the probe, and confirm the zone status again.
(5) Anti-theft performance test After the working area of the defense zone is normal, according to the requirements of the fortification, all possible sizes and shapes similar to the defense should be used to cover the optical axis of the probe with different speeds and different methods. The radio talks to the control center to check whether the alarm condition is normal. At the same time, pay careful attention to whether the alarm host is flashing or unstable. So as not to leave hidden dangers to the alarm system. We call this process verbally. The purpose of the firing test is to test whether the defense zone has the ability to alarm normally, to test whether the scope of the defense zone can meet the predetermined requirements, and whether there is a dead zone of protection.