【摘要】 介绍了一种智能酸碱浓度测试仪,给出测量原理和硬件电路。采用桥路和差动放大电路对铂热电阻温度传感器信号检测放大,用于酸度传感器的温度补偿。软件校准测量电路的零点和满度,软件校正温度传感器和测量电路的非线性。采用高阻、低漂移运放TLC2254组成高阻差动放大电路,用于酸度电极信号测量。印刷电路板上加绝缘环,消除了线路板绝缘电阻对放大电路输入阻抗的影响。软件校正电极偏差,给出校准算法。实验数据表明:温度的测量精度小于±0 2℃,酸度的测量精度小于±0 02pH.设计了RS485总线网络通讯协议。更多还原

【Abstract】 Introduces a kind of intelligent acidity meter,and measuring principle as well as hardware circuit is given.In order to compensate the temperature of acidity sensor,electronic bridge and differential amplifier are designed to detect and amplify the signal of platinum thermistor sensor.The method of software is applied to calibrate zero and full scale of the circuit and nonlinear approach for sensor and circuit.The signal of acidity electrode is detected by a differential amplifier circuit,which consists of high input impedance,low drift operational amplifier TLC2254.And insulating ring technology is adopted to further improve input impedance influenced by insulating resistance of printed circuit board.The deviation of electrode is corrected by software and the algorithm is given.Experiments show that accuracy of temperature and acidity reach to±0 2 ℃ and ±0 02 pH respectively.The communication protocol is designed on RS485 network.更多还原