May 18, 2023

Eight Monitoring Mistakes and Solutions Common in Daily Life

Eight Monitoring Mistakes and Solutions Common in Daily Life

One pan/tilt camera becomes insensitive or unable to rotate shortly after using it. This is a mechanical failure of pan/tilt camera

The occurrence of this kind of situation is usually caused by following types of factors other than product quality factors:

(1). It is only allowed to use a pan/tilt camera that can be equipped with a surveillance camera, and lifting method is used during use.

In this case, lifting method has increased working load of pan/tilt house, causing damage to feeder house drive system and even damage to motor after a short time of use.

(2) The combined weight of surveillance camera and protective cover exceeds load of PTZ camera.

This is a pan/tilt camera specifically for outdoor use, so weight of protective housing is too heavy and there are often problems with camera still panning (especially in vertical direction).

(3) The outdoor PTZ camera is broken or even damaged due to high or low operating temperature, poor moisture and cold protection.

(4).When distance is too long, attenuation ratio of keying data signal is very large, and keying data signal received by decoder is weak.

This time follows

2. When transmitting video, most common malfunction condition is mainly manifested by appearance of this black or white bar on monitor interface, which gradually flips up or down.

Therefore, when analyzing this kind of failure situation, it is necessary to distinguish between two different causes of failure.

To determine if it is a switchable power supply problem or a ground loop problem, a simple method is to only connect output of each surveillance camera that does not have a switchable power problem on control server. If above interference does not appear on computer, then there are no problems with server.

Further, each portable monitor can be connected to video output connector of front camera in principle, and each camera can be tested one by one.

If so, proceed with solution.

Otherwise, interference is caused by other causes such as ground loops.

3. Mahogany scratches appear on monitor

When this kind of interference occurs, normal image will be flooded if it is weak, and it will be impossible to view image (or even get out of sync) if it is severe.

There are many complex causes for this kind of failure.

There may be several reasons:

(1) The video transmission quality is not very good, especially shielding efficiency is low (the shielding network is not good quality copper wire network or shielding network is too thin to achievescreening effect).

In addition, line impedance of this surveillance line is too high, resulting in a large attenuation ratio of data signal, causing malfunction to worsen.

In addition, impedance of this video surveillance line does not exceed 70 ohms, and its parameters exceed requirements, which is first reason for failure.

Since above interference is not necessarily a malfunction caused by a bad monitoring cable, cause of this malfunction must be accurately and carefully assessed.

This can only be considered in terms of poor quality video surveillance cable after other possibilities have been ruled out.

If there is indeed a problem with quality of cable product, it may be a reasonable solution to replace all those cables with quality cables, which is best way to completely eliminate problem.

(2) Because switching power supply of power supply and distribution system is not "clean".

The power supply mentioned here is not "clean", which means that interference signals (60-cycle sine wave) are accumulated in a normal power supply.

The electromagnetic interference in this type of switching power supply mainly comes from equipment using thyristors in network.

Especially high-current, high-voltage thyristor equipment, which pollute power grid very seriously, resulting in pollution of power supply in same power grid.

For example, in power grid, there are frequency modulated power thyristor equipment, thyristor rectifier equipment, thyristor AC and DC conversion equipment, all of which pollute environment by switching power supply.

The solution to this situation is very simple, if you use a clean power supply or a free online UPS power system for entire system, you can solve this problem.

(3) There are strong sources of interference around system software.

It can be discerned in many ways based on research and understanding.

If it is due to this cause, solution is to increase shielding of camera and perform earth processing on video cable conduit.

9 This is a common fault caused by a short circuit between video cable's copper core cable and shield network, and a short circuit.

The form of this kind of failure is to cause deep and chaotic large-scale moiré noise on monitor, so that image is completely destroyed, and image and synchronous signal cannot be formed.

This usually happens with BNC connectors or other types of video connectors.

That is, when such a failure occurs, it will not have a problem with all various signals of entire system, but will only appear in bad procedures of these connectors.

EIf you carefully check these connectors one by one, you may be able to solve this problem.

4. Common faults caused by impedance mismatch in transmission lines

The expression form of this behavior is that multiple vertical bars at same interval interfere with monitor interface, and EMI frequency is basically an integer multiple of line frequency.

This is caused by a characteristic impedance mismatch because video line impedance is not 70 ohms.

You can also say that this kind of interference is caused by impedance and distribution parameters of cable not meeting requirements.

The processing method is usually implemented by "connecting double resistors at beginning" or "connecting resistors in parallel at end device".

Another thing to pay special attention to is that when video transmission distance is very short (usually within 130 meters), aforementioned characteristic impedance mismatch and oversized video cables may not necessarily appear in aforementioned dry condition. .

5. Interference to radiation sources in rooms with laid transmission lines

This kind of interference is mainly caused by strong and high frequency spatial radiation around transmission system, system interface development or central control room.

One solution to this situation is to understand environment when designing system and try to avoid or eliminate radiation as much as possible; equipment is lifted and shielded, and transmission line pipeline is made of seamless steel pipe and well grounded.

An important way to solve above problem is that when you buy video cables, you must make sure of their quality and quantity.

Handle sampling cable if necessary.

6. Mechanical failure caused by defective switching power supply

The switching power supply is incorrect, and there are probably several types: power system route is wrong, or power system operating voltage, output power is insufficient (or wire diameter of power system route to a certain road is insufficient, blood pressure is too high, etc. ), transmission path of power supply and distribution system has a short circuit, short circuit, short-term overvoltage, etc.

In particular, damage to equipment often occurs due to improper power supply or short-term overvoltage.

Therefore, in process of setting up system, before applying power, it is necessary to carefully and strictly check, and never take risks.

7..Because there are many connections between some devices (such as surveillance cameras with wide-angle lenses with three variations and PTZ cameras),if solution is not good, especially route to connect from device If it is not good, there will be problems such as short circuit, short circuit failure, poor insulation layer between lines, wrong wiring, etc., causing equipment damage and performance degradation.

In this case, it should be rationally analyzed according to fault condition, and determine from several lines that line connection is not good enough to cause fault condition.

This will narrow down area where problem occurs.

It should be emphasized that pan/tilt camera may fall and break due to multi-directional movement for a long period of time.

Therefore, it is necessary to pay attention to relationship between equipment and different routes in this situation, which must meet requirements of long-term operation.

8. Problems with quality of machinery products or components themselves.

Theoretically, various equipment and components can have product quality problems.

However, in terms of experience, this is actually a quality issue in product itself, which most often occurs on equipment such as decoders, motorized cameras, and transmission components.

The most important thing to note is that some equipment may not have problems that cannot be used in terms of overall quality, but some performance indicators may not reach indicators indicated in product manual.

Therefore, it is necessary to carry out necessary spot checks on selected products.

If this is indeed a product quality issue, effective way is to disassemble and replace product instead of disassembling and servicing yourself.

In addition, most often problem occurs due to poor hardware settings.

For example, adjusting back focus of a camera is a very delicate and precise task, if adjustment is not accurate, focus will not be very good or there will be a spread in various operations of Jiao triangular wide-angle lens and other problems.

In addition, correct position of some of adjustment knobs of bottom drawer on camera, system specifications, correctness of decoder number switch, or other adjustable position settings will directly affect normal use. of device itself may affect normal operation of entire system.