The Research And Design Of Automatic Biochemical Analyzer Based On STM32

With the development of modern manufacturing level and standard of living, people have higher demands and expectation on the modern medical equipment, including its accuracy, automation, function and so on. At present, the basic principles and realization method of biochemical analyzer are basically identical in the domestic manufacturers. Biochemical analyzer can only be taken in hospitals above the county level because of its price disadvantage. Threrefore, a control scheme is designed to decrease the cost, and the costs of public’s health care can be reduced. More people can enjoy the benefits of modern science and technology.The development history and trend of biochemical analyzer is discussed in the thesis and related key principles, including the principles of spectrophotometer, stepper motor control, incremental encoder, pearl effect and liquid level detection are analyzed. On the basis of these principles, hardware system of the biochemical analyzer is analyzed and designed. The photoelectric conversion subsystem is mainly constructed by ADuCM360 to realize signal acquisition and transmission, including the photoelectric sensor, a variable gain amplifier and multi-channel selector circuits. The subsystems of sample, reagent, reaction and hydraulics are constructed by STM32F429IGT6 to realize the execution of the biochemical analyzer, including the stepper motor, DC motor, switch valve, optical coupling circuits and so on. The temperature control subsystem can realize constant temperature operation by STM32F103C8T6, mainly including temperature acquisition, keys, digital tube display and Peltier control circuit. The communication of between master control chips is realized with RS-485 bus, all data can be transmitted to PC with RS-232 interface.The control variables of biochemical analyzer are huge numerous. The real-time response for the equipment is strict. Therefore, the real-time operating system is adopted for the overall design of the program. Firstly, board-level hardware driver code and chip driver code are programmed. Secondly, according to the requirement, the API function for equipment hardware operation are programmed. Finally, the various subsystems that called API function were designed to be the subtask of the operating system task. The operating system manage these subtasks to realize the operation of biochemical analyzerPCB is designed with the Altium Designer, and the integrity of signal and power supply are considered adequately. According to the debug results of equipment modules and the test results of relevant national index, the function and performance of the designed system can meet the expected requirement.