Nine tips for sharing access controller

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 practicality of the convenience function of the stability operation of the access control system is an important factor and a core criterion for the evaluation of the access controller.

Recommendation one: Choose the access controller with anti-crash and self-test circuit design

If the access controller crashes, it will make the user unable to open the door or close the door, causing great inconvenience to the customer. At the same time, it also increases the maintenance and maintenance costs of the engineering company. The access controller must be installed with a reset chip or used. CPUs with reset function, generally the 51 series CPUs do not have a reset function, and a reset chip is required. 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.

Recommendation 2: Access controller with three levels of lightning protection circuit design

Because the communication circuit of the access controller is distributed and vulnerable to inductive lightning, 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 residual current and voltage at high speed before it can damage the circuit. The lightning protection index requires 4000V induction lightning to have no damage to the equipment for 50 consecutive times. The lightning protection index is high, and the anti-surge and anti-static capabilities of the equipment are 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.

Proposal 3: The storage capacity of the registration card must be large, and the storage capacity of off-line recording should be large enough. The non-volatile memory chip must be used for the storage chip.

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. Must use Flash and other non-volatile memory chips, power down or shock 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 max 485 487 or 1487 chips for cost saving. These chips have weak load capacity, and 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 using high-end communications chips and integrated circuits similar to the MAX3080. The circuit is equipped with a self-test function. If the chip is damaged, the system will automatically disconnect the connection to it, so that the control devices on other buses can communicate normally.

Recommendation 5: The application should be simple and practical, 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 advisable to use high-power, well-known brands of relays with current feedback 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: Reader input circuit needs surge protection and misconnection protection

When the contractor works, it is often live with wiring or debugging. It may be accidental inadvertently picking up the wrong line of the reader or inadvertently causing a local short circuit. If there is no surge protection and misconnection prevention, it is easy to burn. The central processing chip causes the entire controller to be damaged and needs to be sent back to the manufacturer for repairs, which may delay the construction period and increase the construction cost. 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 project supplier find the controller manufacturer or the manufacturer's designated agent to purchase

Only by directly looking for manufacturers or agents designated by the manufacturer to purchase or improve a strong technical service, perfect after-sales service is guaranteed, and a reliable follow-up research and development capabilities to ensure product continuity and advanced. 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 from 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.