12 major faults and treatment methods of the computer room monitoring system


After a monitoring system enters the commissioning phase, the trial operation phase, and after delivery, there may be such failures. These failure phenomena are not working properly, or The system does not meet the technical requirements of the design requirements, or the overall performance and quality are not ideal. Here are some common faults that are provided to netizens for reference.

1. Equipment failure caused by incorrect power supply

Workaround: The power supply is incorrect. There are several possibilities: the power supply line or the power supply voltage is incorrect, and the power is not enough (or a certain power supply) The wire diameter of the line is not enough, the voltage drop is too large, etc.), the transmission line of the power supply system is short-circuited, open circuit, instantaneous over-voltage, and the like. In particular, equipment damage due to power supply errors or transient overvoltages may occur.

2. Due to the poor handling of certain lines, especially the equipment connected to the equipment, the equipment (or components) may be damaged or deteriorated due to disconnection, short circuit, poor insulation between the lines, and incorrect wiring. The device itself is not damaged, but the phenomenon is reflected in the device or component. In particular, the quality of some connectors is poor, the connection process is not good, and it is a common cause of problems.

Solution: In this case, the analysis should be carried out in a calm manner according to the fault phenomenon, and it is judged that the fault is caused by the connection of some lines on several lines. This will narrow the scope of the problem. For example, a camera image with a three-variable lens is normal, but the lens cannot be controlled, so you don't have to check the video output line, just check the lens control line. In addition, the connector, especially the BNC type connector, has very high requirements on the welding process and the connection process of the video cable. If the processing is not correct, even if there is no problem during the debugging and trial running, there is a problem after running for a while. It is particularly worth noting that the camera with the pan/tilt is very common due to the all-round movement, which leads to the disconnection and breakage of the connection. Therefore, the connection between the equipment and various lines to pay special attention to this situation should meet the requirements of long-term operation.

3. Quality problems with the equipment or components themselves. In general, quality problems should not arise with carefully selected commercial equipment or components.

Workaround: Even if something goes wrong, it often happens after the system has been delivered and has been running for quite some time. In addition to the quality problems of the products mentioned above, the most common problems are caused by improper adjustment of the equipment. For example, the adjustment of the back intercept of the camera is a precise work that requires very detailed. If you do not adjust it carefully, there will be problems such as poor focus or defocusing during various operations of the three variable lenses. In addition, the position of some switches and adjustment knobs on the camera is correct, whether it meets the technical requirements of the system, the correctness of the decoder code switch or other adjustable parts settings will directly affect the normal use of the device itself or affect the normal performance of the entire system.

4. Problems caused by incorrect connection between device (or component) and device (or component)


Impact mismatch, such as video connection On a monitor with a high impedance, there will be a bright image, a dithered character, or sometimes no characters.
Communication interface or communication method is wrong. This situation often occurs between the control host and a device with a communication control relationship such as a decoder or a control keyboard. This is mostly due to the choice of the control host and the decoder or control keyboard is not a manufacturer's products. In general, the communication methods or transmission control codes used by different manufacturers are different. Therefore, for the host, decoder, control keyboard, etc. should use the same manufacturer's products.
The drive capability is insufficient or exceeds the specified number of device connections. For example, the number of the main control keyboard and the sub control keys corresponding to the control host is specified. If the specified quantity is exceeded, the system will not work properly. The power of the decoder PTZ is lower than that of the actual PTZ, so it cannot drive the PTZ.

5. The failure of the gimbal. A gimbal does not work or does not rotate at all after use. It is a common failure of the gimbal.

Solution: In addition to the factors of product quality, the following reasons are caused by various reasons. The gimbal that only allows the camera to be installed (that is, the camera sits on the upper part of the pan/tilt) is hoisted in use (ie, the camera is mounted below the pan/tilt). In this case, the hoisting method leads to an increase in the operating load of the gimbal, so that the use of the gimbal drive mechanism may be damaged or even burned out.

The total weight of the camera and its protective cover exceeds the weight of the gimbal. Especially for the outdoor use of the gimbal, the weight of the protective cover is often too large, and the problem that the gimbal does not move (especially in the vertical direction) often occurs. The outdoor head is faulty or even damaged due to excessive ambient temperature, low temperature, poor waterproofing and antifreeze measures.

6. When the distance is too far, the operation keyboard cannot remotely control the camera (including the lens) and the pan/tilt through the decoder.

Solution: This is mainly because the control signal is too far away. The attenuation is too large and the control signal received by the decoder is too weak. At this time, a relay box should be added at a certain distance to amplify the shaping control signal.

7. The image contrast of the monitor is too small, and the image is light

Solution: If the phenomenon is not the control host and the monitor itself, the transmission distance is too long or the video transmission line is attenuated. Too big. In this case, the line amplification and compensation device should be added.

8. Image sharpness is not high, details are lost, color signal loss or color saturation is too small when it is serious

Workaround: This is due to the loss of high frequency end of image signal Too large, so that the signal above 3MHz is basically lost. In this case, the transmission distance is too far, and there is no amplification compensation device in the middle; or because the distributed capacitance of the video transmission cable is too large; or because of the concentrated distribution of the equivalent capacitance between the core wire and the shield wire of the transmission line in the transmission link Caused.

9. Tone distortion

Solution: This is a phenomenon that is prone to occur in long-distance video baseband transmission. The main reason is caused by the high phase shift of the signal caused by the transmission line. In this case, a phase compensator should be added.

10. Operation keyboard failure

Solution: This phenomenon can basically be determined to operate the keyboard "dead" when checking the connection without problems. In the operation description of the keyboard, there are generally methods for solving the "dead", such as "full machine reset", etc., which can be solved by this method. If it can't be solved, it may be that the keyboard itself is damaged.

11. The host does not clean the image.

Workaround: The performance of this fault phenomenon is on the screen after the selection, the interference of other screens is superimposed, or other images are present. The interference of the line sync signal. This is because the quality of the matrix switching switch of the host is poor, which is not caused by the requirement of isolation between images. If the RF transmission system is used, it may also be caused by excessive modulation and mutual modulation of the system.

A large-scale TV monitoring system that operates in conjunction with anti-theft alarms is a highly technical and complex system. Although various fault phenomena may occur, as long as the quality of the selected equipment and equipment is properly controlled and strictly constructed according to standards and specifications, generally no major problems will occur. Even if there is a problem, as long as you calmly analyze and think, "the right medicine", not blindly dismantling and unloading, will solve the problem faster.

12. Poor communication failure

Workaround: The controlled pan/tilt or motorized lens can sometimes operate normally, sometimes it can't (or delay) action, or stop after action. The main reason for this is that there is a problem with the communication line. Check the RS-485 communication terminal matching resistor (120¦¸) on the decoder if the wiring is correct and the line is correct. Or disconnect the host interface and the far-end matching resistor, measure the DC resistance RD of the pin of the single communication piece and the DC resistance R2 of the communication port of the whole system with a multimeter, and compare with the theoretical calculation (R2=R0/n, where n For the number of decoders connected in the whole system), if the difference is too large, it can be considered that there is a problem with the communication chip, and the problematic chip is found by the point-by-point exclusion method. If the communication line has many branches, you can disconnect each branch to determine the approximate range of communication failures.

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