Analysis: Installation and Maintenance of Video Surveillance System
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The cameras and optical transceivers in the surveillance system are often installed on poles that are three or four meters away from the ground, or hung on the wall, which inconveniences the installation, debugging and maintenance of the domes. If construction personnel or maintenance personnel are standing at a height of 34m, they must also carry small monitors, multi-function keyboards, multimeters, or laptops for commissioning and testing, and these devices must be connected to external AC power. This kind of construction and maintenance environment exists. Certain risks and inconveniences, work efficiency is relatively low.
For the installation and maintenance of front-end cameras and video optical transceivers for video surveillance systems, as well as comprehensive applications such as strong electricity measurement, equipment maintenance, and cabling engineering, Guangzhou Cybercomm has developed the STest-895 portable video surveillance integrated tester, which is compact and easy to use. ,Polymer lithium battery power, no external power supply can work for 12 hours. With the handheld video surveillance integrated tester, construction workers no longer need to carry small monitors, multi-function keyboards, multimeters, and other tools, which greatly facilitates the construction and maintenance of security engineering companies. 'Security Engineering Po'.
Installation and maintenance of video surveillance systems In video surveillance systems, because each surveillance point is in a different location, it takes a lot of manpower and time to install front-end cameras (fastballs), transmission equipment, and transmission lines to assist in the rapid detection and deployment of video surveillance systems. Maintaining equipment and transmission lines, saving maintenance costs is a headache for contractors. For the maintenance of the monitoring system, the monitoring equipment and transmission lines are usually overhauled. As shown in Figure 1. Figure 1 shows the installation and maintenance of the video surveillance system. The surveillance center equipment of the video surveillance system, such as the matrix, video server, and video wall, is installed in the monitoring center room. The equipment is centralized in a better indoor environment and the monitoring center equipment is faulty. The probability is small; the front camera and dome are installed outdoors, and the video multiplexer is installed in the outdoor distribution box. The equipment is exposed to the harsh environment such as wind and rain, high summer temperatures and low temperatures in winter, so the probability of failure is high. Relatively high. For the maintenance of the front-end monitoring equipment, it must be able to test the camera image, the image of the fastball, the PTZ control, the optical power of the video optical transceiver, and use a multimeter to test the power supply system, etc., so as to comprehensively solve the problem that the front-end equipment may appear faulty.
Camera maintenance When the monitoring center fails to receive the image, the engineer must first detect whether the camera ball or the dome camera is normal. When detecting camera equipment, engineers use video monitoring comprehensive test instruments to do three aspects of detection: First, use a meter to test whether the camera has an image, the instrument's 3.5-inch color display can clearly display the image captured by the camera, if the meter does not receive The image or the received image is abnormal, indicating that the camera is faulty. Second, the video signal attenuation measurement using the monitor integrated tester is used to measure the camera's video complex level. The normal range is 800-1000mV, and the level is too low will cause the image to change. Dark, the level is too high will cause a virtual shadow; Third, use the instrument's multimeter to measure whether the camera's transformer power supply is normal, the general transformer output is DC 12V, the dome of the transformer output is AC 24V, the transformer is the monitoring system failure rate comparison High accessories.
In the PTZ control and maintenance security monitoring system, the pan/tilt or dome camera is widely used. The monitoring center staff can adjust the camera angle by maneuver. When the PTZ or dome is out of control, or cannot rotate in a certain position, the engineering personnel You need to carry a multi-function keyboard to test whether the pan/tilt or dome camera is rotating normally. However, different manufacturers of PTZ or dome cameras have their own proprietary protocols. When an engineering firm maintains a dome camera, it must bring with it a corresponding multi-function keyboard test. It may be necessary to bring multiple keyboards to test the use of different dome cameras. The engineering staff uses the video monitoring comprehensive tester to solve this problem, because it has embedded more than 30 kinds of protocols such as Pelco-D/P and BOSCH, and it is dedicated to testing the pan/tilt rotation testing function of the pan/tilt rotation. The personnel can rotate the instrument through the instrument and operate the PTZ to observe whether there is a card bit when the PTZ rotates.
The video optical end maintenance video optical transceiver is divided into a transmitting end device and a receiving end device. The transmitting end device is placed in the same outdoors as the camera. The engineering personnel usually perform maintenance testing on the transmitting end device. For the maintenance work of the optical transceiver, it is tested in three steps. First, use a multimeter of the video monitoring comprehensive tester to measure whether the power supply of the optical transceiver is normal, and the general power input is DC 5V; second, measure whether the optical output power of the optical transceiver is normal, and the emission wavelength of the transmitter is 1310n, the receiving wavelength is 1510n, and the 20KM optical transceiver The general transmission power is about -9dBm. Third, test whether the video port of the optical transceiver and the RS485/RS232 communication are normal. The monitoring and comprehensive tester sends the standard color image strip image signal to the video optical transceiver. The monitoring center receives the test color strip sent from the video optical transceiver to indicate that the video transmission is normal. The RS485/RS232 data capture function of the instrument is used to receive the control signal of the optical transceiver. If receiving the control code sent by the monitoring center, it indicates that the optical transceiver's RS485/RS232 communication is normal.
BNC coaxial cable transmission and maintenance of the current video surveillance system, the traditional analog image dominates, IP digital camera due to compatibility issues, temporarily gaining popularity in the future. In general, small-area monitoring systems such as factories and buildings directly use BNC coaxial cables to transmit images. BNC coaxial cables have weak anti-interference, and each BNC cable can only transmit one video, but due to the small monitoring area, the same Shaft cable transmission is relatively low cost, and BNC coaxial cable is widely used. BNC cables are degraded or even interrupted due to ageing, man-made damage, and other reasons. In the maintenance work, it is usually necessary to detect whether the BNC cable has a problem.
During the maintenance of the cable, engineers use the integrated tester to do three steps. First, at the camera end, the BNC cable is connected to the meter and the standard image color bar is sent using the image generator of the meter. Under normal circumstances, The monitor of the monitoring center should receive the same color pattern bar. This step judges whether the BNC line is disconnected, whether the monitoring center receives the image color is normal or not. Second, in the monitoring center, the instrument uses the video signal attenuation measurement function, The attenuation of the measured video complex level after transmission through the BNC cable is too large. Normally, it is 800-1000mV. The phenomenon of image jitter, image dimming, etc. is caused by the attenuation of the video. Thirdly, if the BNC cable is disconnected in the middle, because the BNC cable is buried in the slot, the engineer has no test tool to find the fault point. Using the test function of the integrated test meter, the meter emits a signal and measures the fault. Point location, for the engineering staff to immediately find the location of breakpoints, greatly improving work efficiency.
Optical fiber transmission and maintenance Optical fiber transmission has the characteristics of large capacity, high speed, and high stability. Video monitoring systems increasingly use optical fiber devices such as video optical transceivers and optical transceivers to transmit video images and control signals. Large-scale monitoring systems, such as highway monitoring and monitoring in safe cities, use optical fiber transmission to achieve highly stable video transmission. With the development of optical fiber communication technologies, the prices of video optical cables and optical fiber cables are getting lower and lower, and video monitoring systems use optical fibers. Transmission has become very popular. Optical fiber transmission is usually used for signal transmission between a few hundred meters to 100 kilometers, and detection of fiber optic cables is also an indispensable step. For fiber maintenance, engineers must use specialized fiber-optic test instruments such as light sources, optical power meters, and OTDRs. The stable light source is designed to emit laser light with a high stable power value, and the laser light has a certain attenuation after being transmitted through the optical fiber. The power value after transmission via the optical fiber is measured by an optical power meter, and how much dB value of the optical fiber loss value is calculated. Measuring the time-consuming of the optical fiber must be matched with the light source and the optical power meter in order to prepare to calculate the optical fiber loss; and the OTDR is an instrument for measuring the break point position of the optical fiber. It detects how many kilometers the optical fiber is disconnected, but the OTDR cost Too high, smaller contractors can use optical fiber barriers to measure breakpoints. For small-scale contractors, the most needed optical fiber measurement tool is the optical power meter. Because long-distance optical cables are usually maintained by telecommunication operators or broadcasting and television systems, small-scale engineers only need to measure the power and fiber loss of optical fiber equipment. Finding the problem is enough.
When maintaining optical fibers, engineers use the optical power measurement function of the monitoring integrated tester to switch to the corresponding wavelength to measure multi-mode and single-mode optical fibers. The fiber-connected optical communication devices (such as video optical transceivers and optical transceivers) are normal. In this case, an optical signal will be emitted. If the meter does not receive an optical signal, -70dBm is displayed, indicating that the optical fiber is inaccessible. It is necessary to check whether the optical fiber jumper or the optical cable is disconnected or damaged.
Concluding remarks The video surveillance maintenance comprehensive tester is designed according to the cable transmission and practical application environment of the domestic video surveillance system, which can help engineers solve more practical problems. The use of comprehensive testers by engineers not only achieves the maintenance of cameras, domes, pan/tilts, video optical transceivers, BNC cables, optical fibers, etc., but also eliminates the need to frequently replace relevant test tools during high altitude operations, thereby increasing the number of engineers. The safety and efficiency of working at heights bring great convenience to the installation and maintenance of security monitoring.
