电位型传感器嵌入式遥测系统的研制

Design and Construction of an Embedded Telemetry System for Potentiometric Sensors

研制了一种应用于电位型传感器的嵌入式遥测系统。系统由采样发送端、接收端和计算机组成。采样发送端包括电流放大器、Σ-Δ型模数转换器、微控制器和无线数据传输模块,接收端包括无线数据传输模块、微控制器和协议转换器,接收端通过通用串行总线(USB)接口和计算机连接。嵌入式软件用C语言编写,控制信号的采集和传输;上位机软件用Lab VIEW编写,用于数据存储和显示。系统采集电压信号范围为±1.17 V。为验证该系统的精度和可靠性,应用本套系统和数字多用表对一组电位值进行了对照测试,并用自制的氢离子选择性电极进行了酸度变化响应测试。结果表明,本系统电位测量值可以精确到0.1 m V,且抗噪能力良好,p H响应测量的线性相关系数R2=0.998,变化曲线和商品化的电化学分析仪的结果一致。此系统硬件均由标准芯片组成,采样发送端尺寸为29 mm×14 mm×11 mm,可以用于电位型传感器的远程实时检测。

A new embedded telemetry system for potentiometric sensors was developed. The system consisted of a transmitter unit,a receiver unit and a personal computer（ PC）. The transmitter unit included a current amplifier,a Σ-Δ analog-to-digital converter（ ADC）,a microcontroller unit（ MCU） and a radio module. The receiver unit was composed of a radio module,a microcontroller unit and a serial-to-USB converter module.The receiver unit was connected to an upper computer via a universal serial bus（ USB）. The embedded software written in C language controlled the signal acquisition and transmission. The computer software written in Lab VIEW language was used for data storage and display. The range of the acquisition voltages was from＂1. 17 V to ＋1. 17 V. In order to verify the accuracy and reliability of this system,a control experiment had been done with this system and a digital multimeter. Moreover,a response test of acidity changes had been done with the self-made H＋selective electrode. The results showed that the accuracy of this system could be up to 0. 1 m V and it had strong anti-noise ability. The square of the linear correlation coefficient of the response of the changes in p H values was 0. 998. The curve of the results measured by this system was consistent with that measured by the commercial electrochemical analyzer. The system was built with standard hardware components and the size of the transmitter unit was only 29 mm ×14 mm ×11 mm. It can be easily used for remote and real-time detection for the potentiometric sensor.