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

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

Recommendation 1: Purchase an access controller with anti-crash and self-check circuit design

If the access control controller crashes, it will make the user unable to open or close the door, which will bring great inconvenience to customers, and also increase the maintenance and maintenance cost of the engineer. The access control controller must be installed with a reset chip or selected CPUs with reset function, generally 51 series CPUs do not have reset function, need to install reset chip. At the same time, it must have a self-check function. If the circuit crashes due to interference or abnormal conditions, the system can self-check and start automatically in an instant.

　　Recommendation 2: Access controller with three-level lightning protection circuit design

　　 Because the communication lines of the access control controller are distributed and are prone to be attacked by induced lightning, the access control controller must be designed for lightning protection. We suggest adopting a three-level lightning protection design, first release the large current and high voltage generated by the lightning strike through the discharge tube, and then clamp the current and voltage entering the circuit through the inductance and resistance circuit. Then the TVS high-speed discharge tube discharges the residual current and voltage at a high speed before it damages the circuit. The lightning protection index requires the 4000V induction lightning to cause no damage to the equipment for 50 consecutive times. The lightning protection index is high, and the equipment's anti-surge and anti-static ability will be correspondingly high. Some products advertise that they also have 1500V lightning protection capabilities. In fact, this indicator is that all chips have the ability to prevent lightning and surges at all.

　　Recommendation 3: The storage capacity of the registered card permissions should be large, and the storage capacity of offline records should be large enough, and the storage chip should be a non-volatile storage chip.

　　 It is recommended that the registration card authority needs to reach 20,000, and it is best to store 100,000 offline records. This can meet the storage capacity requirements of most customers and facilitate attendance statistics. Must use non-volatile memory chips such as Flash, and the information will not be lost even if the power is off or is impacted. If the RAM+Battery mode is adopted, the information may be lost if the battery is dead or loose, or subjected to current impact. The access control system may fail.

Suggestion 4: The design of the communication circuit should have a self-checking function, which is suitable for the needs of large-scale system networking

The network of the access control controller usually adopts the 485 industrial bus structure. Usually, many manufacturers choose max485487 or 1487 chips for cost-saving. These chips have weak load capacity, usually, the maximum load capacity is 32 devices, and if there is a communication in the bus Chip damage will affect the communication of the entire communication line, and it is impossible to find which controller chip is damaged. We recommend using high-end communication chips and integrated circuits similar to max3080. This circuit has a self-checking function. If the chip is damaged, the system will automatically disconnect it so that the control devices on the other bus can communicate normally.

　　 Suggestion 5: The application should be simple, practical, and easy to operate

If the control program is applied, it will undoubtedly increase the cost and time of the engineering company’s training for the customer. The customer’s difficulty in mastering the operation of the software will be angry with the engineering company’s service attitude, which will have a bad impact on the collection and order renewal. Customer to the software If you don't understand it, it can easily cause misoperation and cause practical inconvenience. Therefore, we recommend that when choosing an access control controller, engineers must pay attention to whether the operation of the software is simple, intuitive, and convenient. A one-sided emphasis on powerful functions is not suitable for promotion.

　　Suggestion 6: It is advisable to use high-power well-known brand relays, and the output terminal has current feedback protection

　　 The output of the access controller is controlled by a relay. When the controller is working, the relay must be opened and closed frequently, and an instantaneous current flows through each time it is opened and closed. If the capacity of the relay is too small, the instantaneous current may exceed the capacity of the relay, which will soon damage the relay. In general, the capacity of the relay should be more than 3 times the peak current of the electric lock. It is recommended to use a relay with a rated operating current of 7A. The output terminal is usually connected to a large current inductive device such as an electric lock. The instantaneous on and off will produce the impact of the feedback current, so The output end should be protected by components such as varistor or reverse diode.

　　 Recommendation 7: The input circuit of the card reader needs to be protected against surges and misconnections

During construction, the engineering contractor often conducts wiring or debugging with power on. It may be due to accidental negligence to connect the wrong card reader line or accidentally cause a local short circuit. If there is no protection against surge and wrong connection, it is easy to burn. The central processing chip causes the entire controller to be damaged and malfunction, and needs to be sent back to the manufacturer for repair, which may delay the construction period and increase the construction cost. Good protection can prevent the circuit from burning out even if the power supply is connected to the data terminal of the card reader. By anti-surge Dynamic voltage protection can prevent the normal operation of the controller from being affected by the quality of the card reader.

Author: Written by S4A-Access from S4A INDUSTRIAL CO.,LIMITED