说明：  本设计是从经济实惠的角度出发，基于西门子PLC实现的8位密码锁的控制设计，这是一款可以多次更改密码，具有报警功能的PLC电子密码锁控制系统。通过对密码锁的控制要求分析，对PLC控制系统进行了软、硬件设计，并通过仿真实验证明了该系统的实用性，智能控制密码锁开锁、更改、报警、复位、重置等功能。并能在错误次数过多时，将键盘输入锁定，拥有防试探的功能，大大加强了密码锁的安全性。使该密码锁具有保密性强，灵活性高的特点。可将其运用在需要安全保障的一些重要场所。
(This design is from the economic point of view, based on the 8-bit Password Lock Control Design realized by Siemens Plc, this is a PLC electronic password lock control system which can change the password many times and has alarm function. Through the analysis of the control requirement of the password lock, the software and hardware of the PLC control system are designed, and the practicability of the system is proved by the simulation experiment. And when the number of errors is too many, the keyboard input lock, with anti-probing function, greatly enhanced the security of the password lock. The utility model has the advantages of strong confidentiality and high flexibility. It can be used in some important places where security is needed.)