Construction requirements of video access control system

Large capacity: Video access control systems are usually built in rural areas. Smaller villages have dozens or hundreds of buildings, and larger villages may have more than 500 or even close to thousands of buildings. According to the calculation of 50- 100 people in each building, a village may have a population of nearly100,000. It is the basic requirement of video access control to build a system with villages as the unit. It is necessary to build the access control system of all buildings in the village on a platform software, which puts forward higher performance requirements for the platform software and hardware equipment. Therefore, the design capacity of the video access control system platform at village and community level can reach 2,000 buildings with 654.38+ten thousand people, while the video access control system at district and municipal level needs1ten thousand people.

Quick response by swiping the card: There are a large number of people managed in the video access control system, and all the controllers are offline to store all the personnel and permissions at the entrance and exit. For the entrance of a large rental housing community (such as Dagehe, Luohu District, Shenzhen), a controller may store nearly100000 people offline, so it is required that the controller can quickly swipe the card to open the door even if it stores100000 people offline (swipe response time)

Real-time bidirectional active transmission of data: Real-time bidirectional active transmission of data is the basic factor to realize high performance of video access control system. When the network is unblocked, the data of the platform and the front end require two-way real-time transmission; When the network is interrupted, the data will be sent actively after the network is restored.

Efficient video linkage capture: Most people who live in rental houses are migrant workers from Shenzhen, and there will be a rush hour in the morning and evening. Take 1000 building with 65,438+people as an example. In the morning 1 hour rush hour, the number of swiping the card to open the door and taking photos will reach 70,000 to 80,000 times (excluding the number of some elderly people and children), and the average number of swiping the card and taking photos per second is 19.4 to 22.2 times, with a peak of about 48 times per second. In order to cope with the pressure of these actual data, the system must meet the requirements of at least 3 hours and 48 times of screen capture (capture video+capture photos) under the information of 654.38+ 10,000 people, so that the system will not be paralyzed; There should be no obvious delay (no more than 1 sec) in the display of the photos taken; It takes less than 0.2 seconds to open the door by swiping the card. And the platform operation should be very smooth during the peak period.

Multi-workstation login at the same time: the video access control project involves multiple management units, and street offices, village committees, leasing offices and police stations all need their own business operations. In order to facilitate each functional terminal to exercise their respective functions and powers, it is necessary to manage the system accordingly, especially in the peak period of card issuance, supporting multiple card issuing terminals to issue cards to the system at the same time. Generally speaking, the system can provide more than 10 terminals to log in and operate the system at the same time, which can meet the requirements of the system. Lightning protection effect: Because the traditional access control system is installed indoors, lightning protection is generally done during building construction, and the lightning protection level does not need to be too high. Video access control projects are often installed outdoors, so it is inevitable to wire power lines, signal lines and communication lines to the outside. Such lines are the main way to attract lightning. Therefore, the key to the reliability of video access control system is lightning protection performance. According to the author's rough estimation, many video access control projects in Shenzhen are not successful enough because of insufficient lightning protection performance. According to the actual measurement, the lightning protection level of the equipment needs to be above Grade 4 (4KV/2KA) to reach the standard. The equipment selection in video access control involves products that need lightning protection performance, such as access controller, power supply, optical transceiver, camera, hard disk video recorder and so on.

Moisture-proof effect: Moisture-proof is mainly aimed at the video access control project in southern China. Anyone who has stayed in the south must be deeply impressed by the "returning to the south sky" where water drops are condensed on the walls. Many household appliances are easily damaged by severe humidity if they are not properly protected. In the video access control project, because the access of personnel is controlled, it is easy to affect the stability of the system and the access of personnel if the moisture-proof performance is not considered in the equipment selection. Generally speaking, video access control should pay attention to two aspects. On the one hand, the equipment circuit board should be moisture-proof, on the other hand, it should be constructed in a standardized way, and the joint part of the line should be tied tightly with insulating tape.

Resistance to high and low temperature: high and low temperature also affect many devices: access control, power supply, optical terminal, hard disk video recorder and so on. Because video access control is a systematic project, the instability of any link may affect the normal operation of the system. At present, the market of video access control is Shenzhen in the south and Urumqi in Xinjiang in the north. Shenzhen is characterized by high temperature, and Xinjiang is characterized by a large temperature difference between day and night, and the low temperature can be as low as MINUS 30 degrees Celsius. Such an environment makes it necessary to fully consider the temperature adaptation range of products when selecting products. At present, some engineers and friends often have bad equipment, good morning and bad afternoon in actual project application, usually because of the influence of temperature change on the system. The author thinks that in the video access control project, all industrial products (-40~85 degrees Celsius) must be selected to meet the requirements of system reliability.

Wide voltage adaptation: under normal circumstances, the security system should provide stable power supply, and it is best to provide UPS standby power supply for centralized power supply. However, because this is a livelihood project, the cost pressure of the current video access control project is relatively high. In order to save costs, many power sources take electricity from the nearest city. But in places like video access control installation (village in city, farm house, old house, etc. ), the power supply is usually unstable. In order to ensure the stable operation of video access control, we must choose products that can adapt to wide voltage when choosing equipment. Under normal circumstances, it can work stably under the voltage of 10~ 16V, which can meet the requirements of stable operation of the system. Products with wide voltage adaptability include: access controller, card reader, power supply, optical transceiver, hard disk video recorder, etc.

Port reverse connection and wrong connection protection: this is mainly a welfare function. In the process of wiring construction, it is inevitable to connect the wrong wires due to negligence. Many manufacturers of products define this as man-made damage because they have no corresponding protective measures, which is not covered by the warranty. The author believes that truly responsible manufacturers will try their best to make the construction simpler and more effective by improving the reliability of their products during design. Therefore, the function of anti-reverse connection and anti-wrong connection of products is essential, which has a good promotion effect on speeding up the construction progress and improving the construction efficiency.

Reliability of card reader: Card reader is a product directly used by users in video access control. The reliability of card reader is directly related to people's normal travel. In addition to meeting the functions of high and low temperature, wide voltage, anti-reverse connection and anti-wrong connection, the card reader needs strong anti-interference ability and good driving performance because it is directly installed on the iron gate, and metal objects will interfere with the card reader.

Reliability of power supply: the reason why the power supply is taken out alone is because the power supply is too important in determining the stability of the whole system. From the point of view of power supply, it not only meets the above functions of lightning protection, high and low temperature, wide voltage, reverse connection prevention and wrong connection prevention. The following performances also need special attention: power supply stability: long-term operation can ensure continuous and stable rated current output, and it is best to choose 5A power supply; Short-circuit protection: to prevent the power supply from burning out due to line short-circuit or locking fault short-circuit; Circuit breaker protection: In order to ensure the stability of the system, priority should be given to the access control system, which requires at least two outputs of power supply. When the power supply is cut off, the camera power supply will be automatically cut off to ensure the power supply of the access control system; Charge and discharge management: constant current charging ensures the power supply of other front-end equipment, prevents the battery from overcharge and overdischarge, and prolongs the service life of the battery; Fault isolation: multi-channel output, any one of which will not affect the normal work of other channels. Reliability of management platform: video access control project manages rented houses, with dozens of small villages and thousands of large villages. A corresponding platform will manage 65,438+10,000 people and thousands of doors. At present, the technical standard of video access control clearly requires that all data should be uploaded actively in real time, and important information should be captured with video photos. People usually go in and out after work in the morning and evening. In this way, a large amount of data is generated. According to the records of 654.38 million people, 80% of them go to work for an hour, with an average of at least 22 records and 44 snapshots per second. It is normal for a certain peak point to record 50 trips per second. Under such conditions, it is required that the data of the platform can be displayed in real time, and the authorization and data registration of the platform can be operated smoothly. This reliability is very hidden, and many customers have suffered great losses and even affected the acceptance because they did not consider the reliability of the platform when choosing the model.