How to choose an access controller

The access controller is the core part of the access control system and is the soul of the access control system. The quality and performance of the access controller directly affect the stability of the access control system. The stability of the system will directly affect the work and life order of the users of the access control system, and even affect the safety of life and property.

At present, there are many door access controllers on the Chinese market, and their functions are almost the same, but their quality is uneven. Therefore, the selection of products is particularly important for the engineering company. So how do you choose a high quality access controller? The stability of the access control system, the convenience of operation, and the practicality of functions are important factors and core standards for the evaluation of the access controller.

Advice 1: Buy an access controller with anti-dead and self-test circuit design. If the access controller crashes, it will make the user unable to open the door or close the door. This will bring great inconvenience to the customer and also increase the number of projects. For maintenance and maintenance costs, the access controller must be equipped with a reset chip or a CPU with a reset function. Generally, a 51 series CPU does not have a reset function and requires a reset chip. At the same time, it must have a self-test function. If the circuit crashes due to interference or abnormal conditions, the system can self-check and perform self-start in an instant.

Proposal 2: The access controller with three levels of lightning protection circuit design. Because the communication circuit of the access controller is distributed, it is vulnerable to inductive lightning. Therefore, the access controller must be designed for lightning protection. We propose to adopt three-level lightning protection design. First discharge the large current and high voltage generated by the lightning strike through the discharge tube, and clamp the current and voltage into the circuit through the inductance and resistance circuits. The TVS high-speed discharge tube then releases the residual current and voltage at high speed before it can damage the circuit. The lightning protection index requires that 4000V induction lightnings have no damage to the equipment for 50 consecutive times. The lightning protection index is high, and the anti-surge and anti-static capability of the equipment will be correspondingly high. Some products advertise that they also have a 1500V lightning protection capability. In fact, this indicator is available on all chips and does not have the ability to prevent lightning and surge.

Recommendation 3: The storage capacity of registered cards must be large, and the storage capacity of off-line recording should be large enough. Non-volatile memory chips must be used for memory chips.

It is recommended that the number of registered card rights need to reach 20,000, and the number of offline storage records should be 100,000. This can be suitable for the vast majority of customers' requirements for storage capacity, facilitating attendance statistics. Non-volatile memory chips such as Flash must be used, and power loss or impact information will not be lost. If the RAM+ battery mode is used, information may be lost if the battery is dead or loose, or if it is subjected to current surges. The access control system may fail.

Recommendation 4: The design of the communication circuit should have a self-detection function and meet the needs of large-scale system networking.

The access controller's networking is usually networked using the 485 industrial bus structure. Usually, many manufacturers choose to use the max 485 487 or 1487 chip for low cost. These chips have weak load capacity. Usually the maximum load capacity is 32 devices, and if the bus has A damage to a communication chip will affect the communication of the entire communication line, and it is impossible to find out which controller chip is damaged. We recommend the use of a high-end communications chip and integrated circuit similar to the MAX3080. This circuit has a self-test function. If the chip is damaged, the system will automatically disconnect the connection to it, allowing the control devices on other buses to communicate normally.

Recommendation 5: The application should be simple and practical and easy to operate.

If the application of the control program, will undoubtedly increase the engineering company's training costs and time for customers, customers can not easily master the software operation will be angry with the engineering service attitude of the collection and renewal will have a bad influence. Customers do not understand the software and can easily cause misuse, causing practical inconvenience. Therefore, we recommend that when choosing an access controller, the engineering company must pay attention to whether the software operation is simple, intuitive and convenient. One-sided emphasis on powerful features is not suitable for promotion.

Recommendation 6: It is recommended to use high-power, well-known brands of relays with current feedback protection at the output.

The output of the access controller is controlled by the relay. When the controller is working, the relay should be opened and closed frequently, and each moment of opening and closing has a transient current through. If the relay capacity is too small, the instantaneous current may exceed the capacity of the relay, and the relay will be damaged soon. In general, the relay capacity should be more than 3 times the peak current of the electric lock. It is recommended to use a relay rated at 7A. The output terminal is usually an inductive device with large current such as an electric lock. Instantaneous on-off will generate the impact of the feedback current. Therefore, the output terminal should be protected by varistors or reverse diodes.

Recommendation 7: The reader input circuit needs anti-surge and anti-mistake protection. When the contractor is working, it is often live with wiring or debugging. It may be caused by accidental oversight, mistaking the reader's line, or accidentally causing partial damage. Short circuit, if there is no surge protection and misconnection protection, it is easy to burn the central processing chip, resulting in the failure of the entire controller failure, need to send the manufacturer to repair, may delay the construction period, increase construction costs. Good protection can make the circuit not burn out even if the power is connected to the data terminal of the card reader. Through surge-proof dynamic voltage protection, it is possible to avoid the normal operation of the controller due to the quality of the reader.

Recommendation No. 8: It is recommended that the engineering company find the manufacturer of the controller or the agent designated by the manufacturer to purchase only if it is directly to find the manufacturer or the designated agent of the manufacturer to purchase or improve the powerful technical service. The perfect after-sales service is guaranteed and there are Reliable follow-up R&D capabilities to ensure product continuity and advancement. Buying controllers from other sources may have lower prices, but technical support and after-sales services may not be enough.

Recommendation 9: Manufacturers need to provide authoritative quality certification. Manufacturers need to provide authoritative ISO9001 quality certification certificates and product inspection reports of government quality regulatory agencies. And pay attention to verify the authenticity of these documents. The quality of the products certified and supervised by the corresponding third parties will be guaranteed.

There are several errors in choosing an access controller:

Misunderstanding 1: The imported access controller will be better.

The imported controller is very good in product stability and maturity. However, the price is expensive, and because of geographical disparity, the timeliness of the service will not be good, and the service cost will be high. At the same time, due to the differences in cultural background, the foreign users' needs and requirements for access control and management are different from China's national conditions. Many features are simply not suitable for China's national conditions and the needs of Chinese users. Of course, many Chinese access controller manufacturers have small production scales and weak design capabilities. There are few successful application cases, and project companies should also choose carefully. Many Chinese access controller manufacturers, in order to sell their own products, use fraudulent sales made in Taiwan, the United States, Canada, and other countries. In fact, product quality has great problems. This phenomenon should also be treated with caution.

Myth #2: The reader's compatibility is as broad as possible. Some controllers claim to be compatible with readers in various formats, such as the 485 format ABA format wiegand 37 40 and other format readers. Actually, it is not necessary, although these formats are Locally there are some advantages, but it does not conform to international standards, causing problems for future upgrades and capacity expansion as well as anti-jamming. We adhere to the principle of practical stability and compliance with the standards. We recommend that you only need to comply with the international standard of wiegand 26bit. The card reader is fine, and 90% of the imported access controllers comply with this standard.

Misunderstanding 3: The stronger the function, the better.

Many domestic controllers advertise how powerful their products are, and they exaggerate the function of access control functions. Actually, it is the most important for the stability of access control and the simple and functional operation. We propose to shield the powerful extension function, and customers need to provide it to meet their needs. Some functions that customers do not use should not be recommended to customers. This can reduce the cost and maintenance costs of training, and customers can also use it freely. .

Misunderstanding 4: The more expensive the price the better or the cheaper the better.

A good, cost-effective product is the best product. The expensive product may be because his output is not high, or the cost of advertising is too high, it does not necessarily mean that the value of the product is high. Cheaper products may also be the one-sided pursuit of low-cost, reduced investment in protection circuits, or the use of inferior and used chips. Therefore, the contractor must keep his eyes open to make a reasonable assessment of the product's performance and price ratio.