1. Line multiplexing technology: The intelligent monitor and electronic lock are placed in different locations, and the intelligent monitor supplies the power required for the electronic lock and receives alarm and status information sent by it. If communication lines and power supply lines are separated, it is inevitable to increase the number of cable cores and increase safety hazards. Therefore, if line multiplexing technology is used, only one two core cable is used, which achieves the transmission of power supply and information, naturally improving the safety performance of the lock. 2. Data communication and preprocessing technology: The intelligent monitor receives status information from the lock (including opening, closing, first password error, second password error, third password error, etc.), the current value flowing through the electromagnetic actuator coil, and reads the power supply current value of the communication line at that time. The three are combined to form a data block, where the operation status accounts for 1 byte, the power supply current accounts for 2 bytes, and the coil current accounts for 2 bytes. After receiving a data, first compare it with the set threshold value. If it is greater than the threshold value, an over limit alarm will be issued; If it is less than the threshold value, compare the data with the same type of data received on the same day, and retain the larger one. This way, the data stored every day is the maximum value among similar data. 
3. Current monitoring technology:
In order to prevent the man-made destruction of communication lines and the electromagnetic actuator from burning the coil due to the excessive current flowing through the electromagnetic coil for some reason, this paper uses the current monitoring technology in the design of intelligent Combination lock. The current monitor adopts the current/voltage conversion chip MAX471 produced by MAXIM company. This chip can convert the measured current I into an output voltage U to the ground, and has the characteristics of large measurement range, high accuracy, and proportional output voltage U to the measured current I. The output voltage of the current monitor is sent to the A/D converter, and the microcontroller reads the A/D conversion results to understand the changes in current in the circuit. Through analysis, abnormalities are detected in a timely manner and an alarm signal is issued.
