The relay, also known as the contactor control system, is commonly used in the lifting equipment of the Wei state. This control system uses a logic control with contacts in the relay, and uses a magnetic amplifier as the core to form an analog adjustable closed-loop adjustment. For decades, this control system has been flawed due to limitations in component level,

　　The outstanding performance is that the system security protection link is not comprehensive, the work is unreliable, the fault display is not intuitive, and it is difficult to analyze and find faults. The use of a large number of relays, contactors, and other separated electronic components results in a high failure rate and poor reliability. Poor speed regulation performance, large mechanical shock, and poor passenger comfort. The system security protection process is not comprehensive, the work is unreliable, and the fault display is not intuitive, making it difficult to analyze and find faults.

　　The following diagram shows a relay control system. The control program is achieved by connecting relays and contactors with wires, therefore it belongs to the wiring program control system. The input to output control is achieved through wiring programs, and input devices (buttons, travel switches, limit switches, sensors, etc.) are used to send control signals to the system. Output devices (actuators such as contactors and solenoid valves) are used to control various controlled objects (motors, furnaces, solenoid valves, etc.) in production machinery and processes. In relay control systems and electronic device control systems, a control task needs to be completed. The "program" that governs the operation of the control system is achieved by connecting various discrete components (relays, contactors, electronic components, etc.) with wires. This control system is called a wiring program control system. Its program is within the wiring, so it is also known as the wiring program. In the wiring program control system, modification of the control program must be achieved by changing the wiring.