Rolling Mill Parts,Rolling Mill Spare Parts,Rolling Mill Gear Box,Rolling Mill Parts For Sale Taiyaun JDS Machinery And Equipment Co., Ltd. , https://www.jdsmachine.com
In recent years, the perimeter defense system has become a basic and indispensable security subsystem for security systems. It is not only visible in high-end fields such as military factories, military camps, airports, ports, government agencies, but also widely used in residential communities. And maintain a fairly high application growth rate in these areas. Cable anti-theft is a common technical application.
Common cable anti-theft technologies 1. Power carrier communication monitoring system The anti-theft power carrier belongs to a concept derived from the intersection of power and communication. The power carrier communication method (shown in Figure 1) utilizes signal transmission means in the wire and cable anti-theft system to load the detection carrier signal on the cable of the detection range, and the alarm of the monitoring center is connected with the carrier signal on the monitored cable. The cable exit section causes the signal transmission to be interrupted. If the alarm is unable to receive the signal, it will automatically alarm and serve as a warning. The power carrier communication method is currently the most widely used anti-theft method because it transmits carrier signals on the monitored cable and does not require additional lines. Therefore, the power carrier communication method has the advantages of simple installation, concealed detection and wide monitoring range ( More than a few kilometers). However, since the cable can only be stolen when the cable is stolen, it can not deter criminals, and video image forensics is not available. A single power carrier communication is facing the challenge of integration and systemization.
2. Capacitance detection and monitoring system The principle of anti-theft capacitance detection method is to first use a pair of vacant cables to short-circuit the cable terminal, and the other end is connected to the multi-resonant sway of the alarm. When the cable works normally, the oscillator oscillator does not vibrate; When the cable exits the section, the vacant cable becomes a simple capacitor, the oscillator outputs a signal, causing an alarm, and the frequency of the oscillator output signal varies with the position at which the cable is cut. Figure 2 shows the basic model of the capacitance detection method.
3, current detection type monitoring system anti-theft system to determine whether there is transmission current in the cable loop to determine the integrity of the cable system. That is to say, when the cable works normally, the detection system has no response; when there is no current transmission in the cable, the detection system will activate the alarm system. The current detection system cannot be used for cable anti-theft systems with voltage and no current, such as subway tunnels or road tunnel blower power cables. In addition, the system can only alarm when all branch cables of the circuit system are cut off (because the cable branch is completely open, the total current of the cable loop is zero). Therefore, the current detection type monitoring system has a hidden danger of "no police to report".
Analysis of application requirements of cable anti-theft technology in different fields 1. Ground-buried cable anti-theft alarm for street lamps With the rapid development of urban and rural integration, the pace of rapid development of municipal construction has been accelerated. The street lamp is the main body of urban night landscape lighting, which plays an important role. The cable for street lamps has been basically changed from overhead laying to underground laying. The buried lighting of street lighting cables mainly includes: direct burial laying, pipeline laying, cable trenching and so on. No matter which kind of laying, there are hidden dangers of theft, which leads to serious consequences such as economic loss and public security confusion.
The ideal street lamp with buried cable anti-theft system, the most important requirement is that during the light-off period, the alarm anti-theft system requires the end to be without any form of power supply; when the lamp is turned on, the alarm anti-theft system needs to be in circuit state (cable length, street lamp model) Etc.) There is no direct relationship. Whenever possible, multiple lines are used to communicate with the control room via a communication device via a communication device.
2. Highway power cable anti-theft alarm highway mainly uses power cable, and one of the core problems in the development of highway cable anti-theft alarm system is signal detection when cable is abnormal. For highway cable requirements, the main requirements of the anti-theft system are: availability, reliability (low false alarm rate), advanced (alarm differentiation), and scalability (networking with high-speed traffic police systems). Currently, the power carrier communication method is mainly applied, but there are still several problems to be solved:
â—‡Power distribution system transformers have a blocking effect on power carrier communication information;
The three-phase power system in the â—‡ circuit has a signal loss of 10-20 dB. When the communication distance is relatively close, the general carrier signal can only be transmitted on the single-phase line;
â—‡The power line has its own pulse interference. The frequency of China's AC power is 50Hz. There is a secondary peak in the sinusoidal single cycle, then there will be secondary pulse interference, that is, there is 100Hz pulse interference in the power line, which is its inherent property;
â—‡ Different signal coupling modes correspond to different power carrier communication signal losses;
â—‡ Power lines can cause data signals to deform.
In summary, the power carrier communication method in cable anti-theft system is worthy of research and development. It also shows that China's power carrier cable anti-theft system technology is not fully mature. The best cable anti-theft system in China is currently a certain Hangzhou company that manufactures anti-theft cable systems.
The perimeter alarm system uses a technology such as microwave, active infrared, electronic fence to form a "protective wall" that is visible or invisible at the boundary of the protection. When a wall-breaking behavior occurs, the detector of the corresponding zone will issue an alarm. The signal is sent to the alarm control host of the control center to display the alarm position while emitting sound and light warnings. It can also link the perimeter analog electronic screen, or even the linkage camera monitoring system, access control system, and strong electric lighting system.
In recent years, the perimeter defense system has become a basic and indispensable security subsystem for security systems. It is not only visible in high-end fields such as military factories, military camps, airports, ports, government agencies, but also widely used in residential communities. And maintain a fairly high application growth rate in these areas. Cable anti-theft is a common technical application. 
Analysis of common cable anti-theft technology and application requirements in different fields
The perimeter alarm system uses a technology such as microwave, active infrared, electronic fence to form a "protective wall" that is visible or invisible at the boundary of the protection. When a wall-breaking behavior occurs, the detector of the corresponding zone will issue an alarm. The signal is sent to the alarm control host of the control center to display the alarm position while emitting sound and light warnings. It can also link the perimeter analog electronic screen, or even the linkage camera monitoring system, access control system, and strong electric lighting system.