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Security system common faults and solutions

Sep 18, 2017

solar cctv monitor


Security system common faults and solutions


A major, burglar alarm and video surveillance systems operating linkage, is a high-tech, a complex system. After a monitoring system into the commissioning phase, the commissioning stage and delivered, equipment failure caused by improper power supply, power supply due to error or transient overvoltage damage to equipment, connect the device handled properly, it is likely to fail this kind of phenomenon Such as: can not run properly, the system does not meet the design requirements of the technical indicators, the overall performance and quality is not ideal, that is, some "soft problems." These problems are unavoidable for a monitoring project, especially for a complex, large-scale monitoring project. Here we elaborate on the problems and corresponding solutions.

 

1, the monitor produces a deeper and more chaotic large area of moire interference, as well as all the image damage, not form an image and sync signal.

 

Due to video cable cable and shielded wire short circuit, broken circuit caused by the failure. This failure occurs mostly in the bnc connector or other type of video connector. That is, this kind of fault phenomenon occurs, often not the whole system of the various signals are out of the problem, but only in those bad joints on the road. As long as carefully check these joints one by one, you can solve it.

 

2, the power supply equipment failure caused by incorrect, power is not correct there are several possible substantially.

 

Supply line or supply voltage is not correct.

 

Power is insufficient (or a passage diameter supply line is insufficient, excessive blood pressure, etc.).

 

Transmission line power supply system short-circuit, open circuit, transient overvoltage.

 

Especially due to error or momentary power supply overvoltage situations occur resulting in damage to the equipment, therefore, before the commissioning, power supply before, be sure to carefully check with the strict examination, should never be taken lightly.

 

3, three variable lens camera and PTZ does not rotate / lens does not move

 

These devices have a lot of links, often there will be open circuit, short circuit, poor line insulation, mistaken wiring, etc. lead to damage to equipment, performance problems.

Of particular note is that with PTZ camera due to the full range of movement, a long time, resulting in a drop connection, torn apart are common. Therefore, pay special attention to a variety of devices connected to the line in this case shall meet the requirements of long-term operation.

 

4, the quality of the equipment or components themselves.

 

In theory, a variety of equipment and components are likely to have quality problems. But from the experience point of view, purely the quality of the product itself, mostly in the decoder, electric head, transmission parts and other equipment. It is worth noting that some of the equipment on the whole may not be able to use the quality of the problem, but from some technical indicators are not on the product specification given the indicators. It is necessary to carry out the necessary sampling of the selected product. The product quality problems indeed, the best way is to replace the product, and should not be disassembled to repair themselves.

5. problems due to improper adjustment of the equipment produced.

 

Such as the camera after the intercept of the adjustment is very detailed and accurate work, if not carefully adjusted, there will be a poor focus or three variable lens in the operation of various defocus occurs when the problem.

 

Some position switch and the adjustment knob on the camera is correct, meets the technical requirements of the system, a decoder or other adjustable parts of the coding switch settings are correct or not directly affect the normal use of the device itself or affect the normal performance of the system.

 

8, the monitor on the wood grain interference.

 

The presence of this kind of interference does not overwhelm the normal image at a slight time, and the image can not be viewed when it is serious (even breaking the sync). This kind of fault phenomenon is more complicated and complicated. There are several reasons for the following:

 

The quality of the video transmission line is not good, especially the poor shielding performance (shielding network is not a good quality copper wire mesh, or shielding network is too thin and not shield). At the same time, the line resistance of such video lines is too large, resulting in large attenuation of the signal is also the cause of the increase. In addition, the characteristic impedance of such video lines is not 75 ohms with the main parameter exceeding the specification and is one of the causes of intentional. As the interference caused by the phenomenon is not necessarily a video failure caused by the failure, so the reasons for this failure in the judgment to be accurate and careful. Only when the exclusion of the other possible, from the video line to consider the bad point of view. If the cable is really the quality of the problem, of course, the best way to all of this cable all replaced, replaced by the required cable, which is the best way to completely solve the problem.

 

Since the power supply system is not "clean" caused. The power supply referred to here is not "clean", meaning that an interfering signal is superimposed on a normal power source (50-week sine wave). And this power on the interference signal, and more from the power grid in the use of thyristor equipment. Especially high current, high voltage thyristor equipment, the pollution of the power grid is very serious, which led to the same power supply in the grid is not "clean." For example, the power grid in the high-power SCR frequency control device, SCR rectifier, SCR AC-DC converter, etc., will be on the power supply pollution. The solution to this situation is relatively simple, as long as the entire system using clean power or online ups power supply can basically be resolved. ]

 

There is a strong source of interference near the system. This can be judged by investigation and understanding. If this is the case, the solution is to strengthen the camera shield, as well as the video cable for the grounding of the pipeline and so on.

9, the monitor screen to produce a number of equal spacing of the vertical bar interference, interference signal frequency integer multiple.

 

Due to the characteristic impedance of the transmission line does not match the fault phenomenon: this is due to the characteristics of the video transmission line impedance 75 ohms is not caused by impedance mismatch caused. It can be said, this interference is generated by the characteristic impedance of the cable and video distribution parameters do not meet the requirements of integrated caused.

 

The solution is generally solved by means of "start-end series resistance" or "terminal-connected resistance". In addition, it is worth noting that the video transmission distance is very short (usually within 150 meters), the use of the impedance mismatch and the distribution of parameters of the video cable is not necessarily the above interference phenomenon. The fundamental way to solve the above problem is to ensure the quality of the video cable. If necessary, the cable should be sampled for testing.

10, the monitor on the screen to produce a number of thin stripes of interference.

 

This interference is mostly due to the fact that there is a strong, more frequent space radiation source near the transmission system, the system front end or the central control room.

 

One solution to this situation is when the system is established to deal with surroundings understand, or try to avoid as far as possible away from the radiation source:

 

Another approach is that when the radiation source can not be avoided, and the front end of the shield to strengthen the central device, and the transmission line steel pipe and tubing is well grounded.

 

11, PTZ failure

 

A PTZ in the use of shortly after the operation is not working or can not turn, is a common fault PTZ. The emergence of this situation to remove the product quality factors, the general is the following reasons:

 

(1) only allow the camera is installed in the head, when used in the way of lifting. In this case, the lifting method led to the PTZ operating load increased, so the use will soon lead to the rotation of the PTZ mechanism, or even burn the motor.

 

(2) the total weight of the camera and its protective cover over the head of the head. In particular, the use of outdoor PTZ, often the weight of the protective cover is too large, often appear in the head and not move (especially the vertical direction does not move) the problem.

 

(3) outdoor PTZ due to environmental temperature is too high, too low, waterproof, anti-freeze measures failure and even damage.

 

12, when the distance is too far, keyboard can not be remotely controlled camera (including a lens) and head by the decoder.

 

This is mainly because the distance is too far, too much attenuation of the control signal, the decoder receives a control signal is too weak to cause. In this case the installation should relay box over a certain distance to amplify shaping control signal.

 

13, the monitor image contrast is too small, the image is light.

 

This phenomenon is not the main machine and the monitor itself is not the problem, that is, too far away from the transmission or video transmission line attenuation is too large.

 

In this case, the circuit should be added and compensated for the device.

 

14, the image clarity is not high, the details of the part of the loss, serious color signal loss or saturation is too small.

 

This is due to the high frequency of the image signal loss is too large to 3mhz above the frequency of the basic loss caused by the signal.

 

Such as the situation or because the transmission distance is too far, and the middle without amplification compensation device; or because the video transmission cable distribution capacitance is too large; or because the transmission link in the transmission line between the core and shield line appears a centralized distribution of the equivalent capacitance Caused.

 

15, color distortion.

 

This is in the long-distance video baseband transmission mode prone to the phenomenon of failure. The main reason is caused by the high-frequency phase shift of the signal caused by the transmission line is too large. This situation should be added to the phase compensator.

 

16, operation keyboard failure.

 

This phenomenon in the inspection line no problem, basically can be determined as operating the keyboard "crash" caused. Keyboard operating instructions, generally have to solve the "crash" approach. Such as "machine reset" and so on, can be used to solve this method. If you can not solve, it can be the keyboard itself is damaged.

 

17, the host of the image switch is not clean.

 

This fault phenomenon is the performance of the screen after the election, superimposed with other paintings of the interference, or other images of the line synchronization signal interference. This is because the host or matrix switch bad quality, not the image of this isolation caused by the requirements.

 

If you are using a radio frequency transmission system, it may be the system of cross-modulation modulation caused by excessive modulation.

 

18, digital hard disk video recorders can not start, there may be the following reasons.

 

The host system power switch failure; host power supply damage; host motherboard or cpu card bad; the main system hard disk boot zone damage, or hard disk itself failure; operating system is destroyed; for the above reasons to carefully analyze, one by one rule out.

 

19, digital hard disk video recorder crash (on-site monitoring of the image freeze or map

 

The problem is expressed in: the power supply line or power supply system is not correct voltage, power is not enough (or a road power supply line is not enough, copper resistance is too high, the line pressure drop is too large, etc.), power supply system transmission line short circuit, Instantaneous overpressure and other aspects. So that the front-end monitoring equipment and terminal display system does not work, such as PTZ can not rotate and monitor the image is not clear and so on. Especially due to power supply error or instantaneous overvoltage caused by equipment burned. Therefore, in the system debugging process, do not rush to power, before power, be sure to follow the design or drawings carefully and strictly check and check to eliminate blind operation.

 

21, large screen maintenance

 

Large screen in use, due to the high temperature inside the machine and electrostatic attraction, the surrounding dust and fumes will quickly gathered to the machine, the components of the corrosive effect, so that gradually deterioration of the formation of semi-short-circuit state, excessive dust and not timely Cleaning will cause the circuit short circuit, leakage ignition. For the daily cleaning care, large screen with a dry cloth can be wiped; not water, easy to leave water marks; usually should protect the big screen, do not let a variety of tools, relatively high density of hard objects such as large screen, When faced with large screen black screen and other unusual circumstances, such as their own simple repair, need to disassemble, then notify the manufacturers.

 


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