Design Of PCR Instrument Master Control System Based On STM32

The PCR technology is an important part of genetic engineering.Digital PCR as the most advanced third-generation PCR technology,compared to the second-generation PCR technology,it has more excellent sensitivity,specificity and accuracy.With the development of semiconductor technology and electronic technology as well as the constant innovation of the microcontroller industry,the digital PCR instrument develops in the direction of digitalization and automation.Based on the operational and functional requirements of the digital PCR instrument,this paper focuses on the hardware and software designing of the control system,as well as testing and analysis the performance of this control system,details as follows.(1)Designed the master control system hardware circuit.This article uses STM32F103ZET6 as the main controller,and adopts a modular design method to design each hardware module to meet the control function and its performance.The goal is to fully utilize hardware resources and reduce hardware costs.The main hardware modules include power module,main controller module,three-dimensional mechanical arm motor drive module,optical encoder module,ferroelectric memory module,washing pump drive module,trough type photoelectric sensor module,ten-way valve interface module,UART communication module,and program download module.(2)Designed the underlying driver software.This article is based on the?C/OS-III operating system,around the STM32 main controller and according the operation method of each hardware module to design the underlying program.First of all,a simple and efficient communication protocol for communication between host and slave is designed in this article,and in the data receiving process,using the limited time to determine whether the data is received completely.This prevents data reception from being incomplete when the data content is the same as the frame footer data.Then,based on the I~2C bus and according the read/write requirements of the ferroelectric memory to designing the corresponding read/write program.Also the parameters of this topic stored in ferroelectric memory and its default value are listed.(3)Designed the three-dimensional mechanical control program.This paper accords the parameters of the encoder,screw,etc,to obtaining the calculation formula of the position and rotation speed.Then,In order to realize the double closed-loop control of the position and rotation speed,a position PI controller and a rotational speed PI controller are designed respectively,and the values of K_pand K_iof the two PI controllers are obtained by trial method.Finally,according to the different initial positions of three-dimensional mechanical arm,the reset program of the three-dimensional manipulator is designed.(4)Designed the washing pump control program.By comparing the advantages and disadvantages of trapezoidal acceleration and“S”type acceleration,trapezoidal acceleration is used in this paper to control the movement of the stepper motor inside the washing pump and design its acceleration and deceleration process.According to the operation method of digital PCR instrument,this paper designed the test program in the upper computer.The test software has the characteristics of friendly interface and simple operation.(5)Tested the digital PCR instrument master control system.This design mainly tests and analyzes the communication module and pipetting accuracy of the digital PCR instrument,and the position accuracy,rotational speed accuracy of three-dimensional mechanical arm inside the digital PCR instrument.The test results show that its various indicators meet the design requirements of the control system...