土壤电导率测量系统开发

介绍一种基于“电流一电压四端法”的土壤电导率测量系统的开发。该测量系统由传感器单元、数据采集器USB2808和计算机软件等部分组成。传感器单元包括4个电极，2个外侧电极用来向土壤中输入交流恒流激励信号，2个内侧电极用来检测与土壤电导率相关的电压降。数据采集器USB2808用来将传感器测得的模拟电压信号转换为数字电压信号。计算机软件使用VC＋＋来开发人机交互界面，实现了输入恒流值、内侧电极电压降、土壤电导率等值的显示，并可将这些值保存到数据库中。试验结果表明该测量系统可以有效输出土壤电导率的值。

Measurement System Development of Soil Electrical Conductivity

This paper describes the measurement system development of soil electrical conductivity based on four-electrode method. It includes three parts which are the sensor, data collector and computer software. The sensor has four metal probes. Two outside probes transmit constant alternating current into the soil and two inside ones detect the voltage drop in the soil. The data collector USB2808 converts the analog signal from the sensor to digital signal. Computer software is de- signed to display constant current, voltage drop and soil electrical conductivity, and then pups these data into database. The results of experiments show the measurement system is able to measure the soil electrical conductivity effectively.