便携数字式pH检测仪的设计

Design of portable digital pH measuring instrument

设计了一种基于工业pH玻璃电极传感器的高精度数字显示pH检测仪。系统采用MSP430G2553作为主控核心,pH电极mV级电压和温度补偿电压经低温漂,高信噪比的信号调理单元差分放大,滤波之后送至A/D转换器,程序上采用两点校正算法标定pH值,并对pH溶液温度误差进行补偿,经微处理器运算、量化后将被测液pH值进行液晶显示并通过微型打印机显示出结果。该系统通过RS485总线进行数据通信,引入消息机制,解决高速响应和低速处理的矛盾。通过大量酸碱性溶液测试发现,pH检测误差在±0.3%之间,表明该系统稳定可靠、精度高、使用方便。

This paper introduces a digital pH instrument detecting system based on industrial pH electrode sensor.The system adopts MSP430 G2553 as the main control core.pH electrode mv level voltage and temperature voltage by the operation of amplification,filtering is then sent to the A/D converter,and the program uses temperature compensation,calibration algorithm by the microprocessor operating and quantifying the pH value to be liquid crystal displaying and through the micro printer prints outputs the results at last.The system uses the RS485 bus for data communication,and introduces the message mechanism to solve the contradiction between high speed response and low speed processing.A large number of tests show that the system is stable and reliable,high precision,easy to use.