pH值温度监测显示系统研究

pH值计是一种常用的仪器设备,主要用来精密测量液体介质的酸碱度值,广泛应用于工业、农业、科研和环保等领域。根据微机式医学仪器设计实验教学的需要,设计了一种便携式温度、pH值测试仪。温度测量部分选用的是DALLAS公司推出的DS18B20可编程的单总线数字温度传感器。在进行pH值测量的同时,利用测得的溶液温度值在软件中实现pH值测量的温度补偿;pH值测量部分是以E201C实验室pH复合电极为传感器,采用电位法测量溶液的酸碱浓度,使用精密低功耗仪表放大器INA128组成差分放大电路,测量溶液相对参考电极电位差,再经8位串行模数转换器TLC549转换得到数字信号,由单片机进行计算处理。

System Research on Monitoring and Displaying of pH Value and Temperature

pH meter is a commonly used equipment, mainly for precision measurement of the pH value of the liquid medium, it is widely applied in industry, agriculture, scientific research, environmental protection and other fields. The paper designs a kind of portable temperature ＆ pH meter, to meet the needs of the ＂Design of Microcomputer-based medical instrumentation＂ experimental teaching. DS18B20 -Programmable Resolution 1-wire Digital Thermometer is used for the part of temperature measurement. The temperature value is used in pH measurement at the same time, for the temperature compensation of pH measurements; Potential method is used for the measure of acidity or alkalinity with the sensor of E201C pH electrode, followed a precision low power instrumentation amplifier INAI28 as differential amplifying to measure the potential difference between the to - be - measured solution and reference electrode. A TLC549-8-bit Analog-To-Digital Converter with Serial Control is selected for digital signals for the MCU to computing.