基于ARM的液体表面张力系数测量系统设计

Measurement System of Liquid Surface Tension Coefficient Based on ARM

为了解决传统的液体表面张力系数测量中存在的精度低、稳定性差的问题,设计了一种基于ARM处理器的液体表面张力系数测量仪。采用功能强、频率高的STM32芯片作为主控制器,并对用拉脱法测液体表面张力系数的测量装置进行了改进;系统采用集成了放大器和24位A/D转换器的芯片HX711对力敏传感器输出的模拟信号进行放大并数字化,采用中位值平均算法对ADC输出的数据进行滤波;对传感器进行静态标定,获得其线性特性关系,并分析系统的测量误差;最后通过LCD显示屏直接显示测量拉力的大小,提高了测量效率。实验结果表明,相较于传统测量仪器,该液体表面张力系数测量仪有效提高了测量精度,误差较小,且重复性好。

In order to solve the problems such as low precision and poor stability in the experimental instrument of traditional liquid surface tension coefficient,a liquid surface： tension coefficient instrument based on ARM microprocessor is designed. The STM32 which has powerful functions and high frequency is used as the controller to improve the experimental device for measuring the liquid surface tension coefficient with pull-off method. This system uses HX711 to amplify the electric signal output from the force sensor, and converts the analog signal to digital signal. The median average filtering algorithm is used to filter. The static characteristic of the sensor is calibrated, getring the linear relationship between features, and the error of the measuring system is analyzed. The LCD screen is used to display the size of the tension directly which improves the efficiency of the measurement. The experimental results indicate that compared with the tradtional instrument, this liquid surface tension coefficient instrument improves the measurement accuracy effectively, decreases the errors and has good repeatability.