General introduction of CCTV surveillant system

1) Important points for maintenance of surveillant equipments:

1. Check the power socket to the cameras regularly to prevent the plug from falling off.
2. Ensure constant supply voltage for each camera and surveillant center.
3. Cautions for cameras at lower position indicating no touch for non-surveillance supervisor is suggested.
4. Special staff should be appointed for the charge of surveillant equipments in the surveillant center, operation is not allowed for non- surveillance staffs.
5. Make sure all the equipments in the surveillant center are powered off every night in the case of nobody exist.
6. Wipe and maintain the surveillant equipment frequently.
 
2) FAQ and answers for CCTV system – Video splitter
1. Abnormal states of power supply results in locked video splitter. Replace the power supply.
2. Video screen is disturbing; it’s the poor connection of video line when connected to BNC end.
3. Disorder working states of the video splitter due to incorrect setup of program, try the setup again.
4. Playback is not available; video may be connected to the wrong port.
5. Simplex video splitter is for record only rather than playback. Duplex or half duplex are all ok.
 
3) FAQ and answers for CCTV system – Matrix
1. If it has been programmed correctly without any omissions.
A. If the allocation and authorization of the monitor has been programmed correctly when sub keyboard is used.
B. If the alarm equipments has been properly connected when setup alarm surveillance and video. If they are properly programmed (data collision of the related equipments).
C. Pay attention to the data port provided in the user’s manual when it’s connected to external controlled equipments, such as speed dome, decoder, alarm equipments, etc.
 
 
2. Matrix failures
A. There is no display when it’s turned on, please check the fuse.
B. There is no display on the matrix container with 32 channels when it’s turned on. Exam the flashboard and check if the LBD is in normal working status, if not, unplug the board and plug it again.
C. Shift to a normally displayed screen when there is no output in a certain channel to check and determine whether the problems are with the matrix or others.
D. Control fails, please check if the correct control port has been chosen and if the controller is encoded; try another port.
 
4) FAQ and answers for CCTV system – Decoder
1. Power indicator is not lit after the decoder is powered on.
A. Check if the power supply has been connected to the terminal.
B. Check if the power fuse has been damaged.
2. Fuse is burned once powered on.
A. Check if there are problem with the com of the terminal block.
B. Check the output voltage of the tilt.
 
3. Power led is lit but out of control.
A. if the signal line has been properly connected.
B. if the signal lamp flashes when actuating the power led.
C. if it’s correctly encoded.
 
4. It’s out of control and rotate randomly
A. Check the signal line of control code.
B. Control line for a signal line is too long.
C. Too many decoders have been connected in series (parallel) to a signal line.
 
5) FAQ and answers for CCTV system – Tilt
1. Tilt failures. It is a common failure that a tilt cannot work well or even cannot rotate after it’s used for a while. Reasons besides the quality factor are described as follows:
(1) Hanging installation method has been used to install the camera, for which frontal installation is only allowed. This increased rotation load on the tilt and caused damage on the driving gear of the tilt or even result in burned motor.
(2)Total weight of camera and shield excess the bearing of the tilt. Typically, the weighty shield of the outdoor tilt may result in rotate failures (especially for the vertical direction) of the tilt.
(3) Outdoor tilt may malfunctions or been damaged as a result of too high or too low ambient temperature and poor waterproof and frostproof provisions.
 
2. The camera (including lens) and tilt are out of the remote control of the operating keyboard via decoder due to the long distance, which would cause significantly weakened control signals received by the decoder. In this case, a relay box should be installed at a certain distance to amplify the regulated control signals.
 
3. Low contrast caused light colored video image. It’s either the problem with the control unit and the camera or the problem that the transmission distance is too long or the performance of the video cable is significantly reduced. In this case, circuit amplifier and compensator should be added.
 
4. Video image is not clear enough, details are lost, or worse more, the colored signals would lose or color gamut would be too low. The reason is that the high frequency terminal of the video signal has been significantly reduced, resulting in the loss of signals with frequency above 3MHz. This is the result of the long transmission distance without provision of amplifying and compensating devices, or too high distributing capacitance of the video transmission circuit, or centralized equivalent capacitance exist in the transmission circuit between core wire and shielding wire.
 
5. Color distortions. This failure occurs frequently for the long distance baseband video transmission. The main reason is about the great phase shift in the high frequency section caused by the transmission line. In this case, phase compensator should be provided.
 
6.Operating keyboard failures. It’s either the result of the poor connection of the cable or the ‘halted’ keyboard. Please check keyboard user’s manual for how to solve the ‘halted’ keyboard problems, such as by ‘unit reset’. If it cannot work, please check if the keyboard has been damaged.
 
7. The images cannot be switched completely by the main unit. To be exactly, the chosen and switched image was interfered by the overlap with the other images or the synchronized signal from the other images. The reason is that the main unit matrix switch is with bad quality and cannot meet the space requirements between images. If radio frequency transmission system has been used, the reason would be the great cross modulation and the intermodulation in the system. A large-scale CCTV system, which operates combined with alarming system, is complex and integrated with high technology. Failures could be avoided if quality of the devices and equipments is ensured and the operating regulations and rules have been abided by, if failure appears, try to calm down and analyze the problem with patience, don’t disassemble and teardown unreasoningly, any problem could be solved quickly.
 
(1) Equipment failures due to power supply errors. There are some possibilities for power supply errors: errors in power circuit or the supply voltage, power is insufficient (over reduced voltage, etc.), short circuit, cutoff or transient overvoltage occurs in the transmission line of the power supply system, etc. So, in the system debugging process, please check and exam carefully before supplying power.
 
(2)Certain equipments (such as camera with 3 motorized zoom lens and the tilt) are with several links, if handled improperly, especially for those circuit linked directly with the equipments, then cutoff, short circuit and poor wire insulation would thus incur and result in the damage or reduced performance of the equipments. In this case, please analyze the failures with patience, check wire connection and confirm the specific circuit that caused the failure. In this way, the problem would be focused. The important point is that, it’s a common phenomenon for cameras with tilt that its link line would fall off or break off due to long time and all-direction rotates of the tilt. Therefore, special attentions should be paid to the connections between the equipments and varies link wires to ensure requirements for long time rotate are met.
 
(3)The quality issue of the equipment and components, theoretically speaking, each kind of equipment and parts have the possibility to happen the quality problems. However, from experience,the quality issue of the product itself, always occur in the decoder, the electric Pan & Tilt, the transmission parts, and other devices etc.. It is worth pointing that some equipments may not occur the problem that cann’t be used by overall speaking, but actually some techinc index cann’t achieve the index which gave on  product’s specification. So it must sample inspection for all products.If it’s really belong to product quality issue,the best way is to replace the product,rather than disassemble and repair voluntarily. In addition, the most common prolem is due to the improper adjustment of the equipment.For example, to adjust the back intercept was a very meticulous and precise work, if don’t carefully adjust, it will present the bad focus or happen debunching issue when operat three kinds of variable lens. Otherwise,some switches and control knob's position on cameras whether correct, whether to accord the technical requirements of system,and the decoder code switch or other parts of adjustable settings are correct or not ,which all directly affect the normal use of the equipment itself or affect the normal performance of the entire system.
 
(4)The problem due to the incorrect connection between the equipment (or parts) and equipment (or parts), will approximately occur following aspect.
 
a. The impedance does not match
 
 b. The communications connection or mode does not correspond. This kind of situation mostly occurs among the equipment of the control mainframe and the decoder or control keyboard and so on which have the communications control relations.That is to say, it is due to the products of control mainframe and the decoder or control keyboard etc. are not in the same factory.So it should choose the same factory products for mainframe , decoder and control keyboard etc.
 
c. Driving force insufficient or over the set equipment connection quantity.For instance, some of the image separator have the alarm input interface function,which be showed on the specification connect with alarm probe and long time delay video recorder and so on connection system mainframe consist a system, If we attached the alarm probe to alarm imput end of the image separator, and then the alarm signal from probe have to drive both alarm mainframe and image separator. In such case, the drive power always be insufficient. The electrophoresis is that although the image separator can still give an alarm, but it can not work stablely due to the weak signal , and it leads to the series of the camera image which give the alarm signal switch to full screen but can not stay long,, so the image shows on the monitor still the same split-screen before the alarm unhappened.