What are the common faults and repair methods of access control systems?

I. Access Control System Overview

An access control system (ACCS) is a comprehensive control system based on modern microcomputer identification technology and security management measures. It is primarily used to manage access rights for personnel and items, while also supporting functions such as attendance management and regional linkage. Its core goal is to improve security and management efficiency through intelligent means.

1. Core Components
- Hardware - Card Reader: Supports card, biometric (fingerprint, facial), or mobile phone QR code recognition. It is typically installed at a height of 1.4 meters and away from sources of electromagnetic interference. - Controller: The core of the system, responsible for data processing, permission determination, and device control. It requires a stable power supply (an independent power supply is recommended). - Electric Locks: These include electromagnetic locks (which open the door when power is off, meeting fire safety requirements), electric bolt locks (which support 180-degree opening), and intelligent locks (which are low-noise). Selection depends on the door type. - Sensors and Alarm Devices: Such as magnetic sensors, detect abnormal door status and trigger alarms. - Software - The management platform supports permission settings, real-time monitoring, data logging, and linkage control (such as linkage with the fire safety system).

2. Identification Methods
- Card/PIN: Traditional and low-cost, but easy to copy or leak.

- Biometrics: Fingerprints, irises, and other methods offer high security, but are more expensive and can have rejection rates.

- Mobile App/QR Code: Convenient and supports remote authorization and visitor management.

II. Common Troubleshooting Methods
1. Access Card Unrecognized

- Possible Causes: Card scratches/stains, poor card reader contact, electromagnetic interference.

- Solution: Clean or replace the card; restart the card reader; check wiring connections or install shielding measures.

2. Electric Lock Anomaly - Lock body does not activate - Check the power supply voltage (electromagnetic locks require at least 1A/12V) and measure the voltage at the controller output. - Verify the distance between the lock body and the metal plate (3-5mm is recommended) to prevent interference from foreign objects. - Unusual noise from the lock body - Install a rubber gasket or adjust the screw tension.

3. Remote Control Failure - Network Issue: Check Wi-Fi signal strength and network cable connectivity (test using the Ping command), and restart the router. - Server Status: Contact the service provider to confirm server operation.
4. Abnormal Alarms - False Alarms: Adjust sensor sensitivity, test, or replace the alarm. - Continuous Alarms: Check the door sensor wiring or reset the controller.
5. Power Failure - Indicator Light Off: Replace the power adapter or recharge (backup power supplies require regular maintenance). - Unstable Voltage: Use a separate power supply for the electric lock to avoid current shortages caused by multiple devices sharing the same power supply.
6. Communication Interruption (TCP/IP Controller) - Network Configuration: Check the IP address, subnet mask, and gateway settings, and disable the firewall. - Connection Issues: Replace the network cable or test using a separate switch.

III. Maintenance and Optimization Recommendations

1. Regular Maintenance - Clean dust from the card reader and electric lock, and check for wiring degradation. - Update system software and permissions, and back up the database.

2. Environmental Optimization - Avoid placing strong electromagnetic equipment (such as motors and monitors) near the card reader. - Regularly check the cleanliness of the metal plate adsorption surface of magnetic locks.
3. Emergency Response - In the event of a malfunction, activate a backup mechanical key or remotely reset the system through management software. - Contact the supplier for complex issues and avoid disassembling core components yourself. 4. Expanded Application Scenarios - Smart campuses/office buildings: Integrate a QR code visitor reservation system to achieve a unified reservation, verification, and access control system. - High-security areas: Implement multi-factor authentication (such as facial recognition and fingerprint recognition) and integrate with video surveillance and fire protection systems. These methods can systematically troubleshoot and resolve common access control system issues, ensuring stable operation.