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Access Control System should have a high degree of stability, choose an open hardware platform, support multiple communication methods, lay a solid foundation for interconnection and system integration between devices, and also have standardized and modular components to ensure great Flexibility and scalability.
The outdoor door of the building is more likely to be struck by lightning, causing great inconvenience to the user and also causing great economic losses. Through the investigation and analysis of the causes of these lightning strikes, the main components of the crash are the power box, circuit board, and talker.
First, the main route to lightning strikes
(1) Directly hit mine. Direct lightning strikes the lightning directly on the object. The thundercloud near the ground induces an opposite charge on the protrusion. When the electric field strength between the thundercloud and the ground protrusion reaches the air breakdown strength, it will strike. Wear discharge, this type of thundercloud directly puncture discharge on the ground protrusion is called direct lightning. High buildings and their sides are subject to direct lightning strikes, and direct lightning strikes on the side of a building can be called side impact mines.
(2) Induction of thunder. Lightning strikes a conductor, such as a metal object next to the device, and indirectly strikes the object. Lightning induction is divided into electrostatic induction and electromagnetic induction. The formation of electrostatic induction is due to the induction of a large number of opposite charges on the top of ground projections when the cloud approaches the ground. When the thundercloud and other thunderclouds or other objects are discharged, the accumulated charge on the top of the protrusion suddenly loses its bondage, showing a high voltage and rapidly propagating in the form of lightning waves. The formation of electromagnetic induction is due to direct lightning currents that produce a rapidly changing strong magnetic field in the surrounding space, which induces high voltages in nearby metals. Induction mines are not as violent as thunder but they are much more likely to occur than direct thunder. Because direct lightning strikes only when lightning strikes the ground, it will cause disasters to the ground. Induction lightning, however, strikes lightning regardless of the lightning strikes on the ground, or lightning strikes between thunderclouds may occur and cause disasters. A lightning stroke can occur in a relatively large range and multiple small parts at the same time, and this induced high voltage can be transmitted far through the signal wires, power lines, telephone lines and other metal wires, resulting in lightning The scope has expanded.
Second, access control Intercom System lightning installation
The following measures should be taken to prevent the above major lightning strikes:
1, the power box installation location should be properly selected
(1) Avoid installing on the side wall of the house, especially on the side wall of the projected house, so as to prevent direct lightning strikes.
(2) Avoid installation on the side of a pipe where there is a metal pipe, a gas pipe, etc. Especially, the same side wall that is less than 5 meters from the metal pipe and the air pipe can not be installed.
2. Both the power box and the circuit board should be grounded. The grounding wire should be solid and reliable, and the grounding resistance should be ≤ 0.1Ω.
3, wiring should be correct and reasonable. Power lines and signal lines should be placed indoors to avoid outdoor wiring as much as possible, avoiding the same direction and cross wiring as metal pipes, air pipes, etc., and it is impossible to avoid wiring in the same direction as metal pipes, gas pipes, etc. The distance between the two should be ≥ 5 meters. . The wiring should be laid in a straight line to minimize bending wiring.
4. The power source of the power box should be connected to the power socket. When weather is prevented or weather changes may cause lightning, it is convenient to cut off the power in time to prevent lightning strikes.
Access control intercom purchase eight points one, strong stability
"Stable" is the first choice for the selection of access control systems. It should consider the mature products that are in the leading position in the world as far as possible, pass a number of authoritative certifications, and have many typical users. It has been operating for many years and has been highly recognized in the industry.
In terms of hardware, devices from the controller to the terminal are mature and stable products. As the core of the system, the access controller needs to support the offline mode of operation. It must use flash and other non-volatile memory chips, and the power loss or impact information will not be lost. Failure of the server and terminal to identify equipment does not affect the normal operation of the system. As the management software supported by the system, it should have a stable and reasonable database structure design. Between the hardware and the real-time polling method, the communication connection and address of the hardware should be maintained and monitored. Complete data integrity, reliability, consistency.
Second, extremely strong anti-destructive ability
Access control systems are used to protect people and property, so the system itself must be safe. The high security mentioned here refers to the natural or quasi-natural properties of the product or system. It should ensure the safety of the equipment and system operation and the safety of the operator. For example, the equipment and the system must be able to withstand high temperatures and low temperatures. Hot and humid, and can prevent static electricity, anti-jamming, etc.; on the other hand, access control and security systems should also have anti-human damage features, such as: with tamper alarm.
Third, excellent compatibility
To facilitate future upgrades, capacity expansion, and anti-jamming considerations, it is recommended that terminal identification devices comply with international standards be selected, and that the wider and better the compatibility, the better. Some formats have some advantages in terms of locality, but they do not conform to international standards. They will cause problems for future upgrades, capacity expansion, and anti-jamming. They should adhere to the principle of “practicality, stability, and compliance with standards”.
Fourth, flexible scalability and economy
It is suggested that the number of registered card rights need to reach 30,000, which can be suitable for the vast majority of customers on the storage capacity requirements, facilitate the attendance statistics and business scale expansion. The main equipments should adopt modular design and adopt advanced wiring methods. Through software and hardware upgrades, future system expansions can be achieved without having to make major changes to the system, maximizing the economical principle, and at the same time, products should be cost-effective.
Fifth, powerful software management functions
With the increasingly wide range of applications for access control systems, it is required to implement linkage control functions with other systems such as attendance management, security alarm, parking lot control, elevator control, consumption management, CCTV linkage, and online patrol. Therefore, the system software should have video Interfaces and support for extended functionality.
Six, easy to maintain
The system should be easy to install and configure, simple and popular, and have a unified network management capabilities, easy to maintain.
VII. Purchase of mature brand products at designated agents
A mature brand can guarantee a perfect and powerful service system. This includes two aspects: First, technical support and thoughtful after-sales service for the project; second, reliable follow-up research and development capabilities to ensure continuity and compatibility of new and old products.
Buying from agents can have reliable quality and perfect services. Buying from other channels may have lower prices, but technical support and after-sales service may not be enough.
Eight, product appearance
With the improvement of people's aesthetic standards, while pursuing function and practicality, one can use its design as one of the reference standards in order to realize additional functions of visual enjoyment.
