The software of the automobile air-conditioning fan monitoring system is divided into two parts, namely the Win-dows application of the upper computer and the MC program of the lower computer. The upper computer program belongs to the application program under the Windows operating system. The program is written by the Delphi development tool. The program functions mainly include: control program user interface, communication module and detection process control. The user interface of the control program mainly completes the display of fan status, operating current and voltage, speed, detection items and test results, as well as various buttons for the operator to manually control the detection process. The communication module uses the interrupt mode to pack the instructions of the upper computer and send it to the lower computer. At the same time, it uses the interrupt method to receive various working parameters sent by the lower computer at any time, and then unpacks the working parameters and transmits them to the user interface for display and transmission. The process control section performs process analysis and process control. According to the control parameters of each link of the detection process, various control commands are transmitted to the lower position machine through the communication module. The lower machine outputs the working voltage of the fan and the PWM control signal according to the control command, and analyzes the working parameters of the fan sent by the lower machine. It is determined whether the fan is working normally or abnormally, and the result of the detection is sent to the user interface part for display in time, and the flow of the detection link is controlled according to the detection result of each link of the process, thereby realizing the control of the detection process. The lower computer program can be divided into: program-controlled switching power supply module, USB communication module, fan control module and fan working parameter detection module according to different functions. The program-controlled switching power supply module is the core and key point of the lower computer program. The fan control module completes the control parameters output to the fan mainly including the working voltage and the control PWM signal. The module sends a controlled target voltage command to the programmable switching power supply module according to the detection command transmitted from the upper computer, and sets the primary side protection current and the output protection current of the programmable switching power supply. The PWM control signal of the fan is automatically generated by the MCU's TIM3 timer operating in the PWM mode. The program changes the duty cycle of the PWM to change the control signal of the fan according to the control needs. The fan working parameter detection module mainly completes the parameter detection of the working voltage, working current, working speed and whether the fan is running. The working voltage and the working current are obtained through communication with the programmable switching power supply module. Whether the working and working speed of the fan is obtained by sampling the frequency and duty ratio of the feedback signal by the MIM TIM2 port operating in the input capturing mode. Nonwoven Textile Cross Lappe,Nonwoven Cross Lapper,Cross Lapper Machine,Cross Lapper Nonwoven Machine Changshu Tianli Nonwoven Equipment Co., Ltd. , https://www.tianli-machinery.com