Determining Sensing Area of Electromagnetic (EM) -Based Sensors
Location
Logan, UT
Start Date
3-29-2022 4:15 PM
End Date
3-29-2022 7:00 PM
Description
Electromagnetic (EM) -based sensors are the most popular soil moisture sensors used globally. However, the accuracy of sensors may be altered by aging, and calibrations may be soil-specific. Therefore, sensor calibration is an important issue. Previous research has studied calibration of EM sensors using mixed testing approaches with mixed results. Unfortunately, sensor calibration may be complicated and calibration methods may need to be improved. The objectives of this research are (1) to establish a general framework for calibrating electromagnetic (EM) -based sensors from different manufacturers, and (2) to determine the sensing area of a time-domain reflectometry (TDR) sensor in order to size the calibration cell. Sensing area is the region in which the sensor can detect a change in water content. Determining the sampling volume of sensors being used is important to understand prior to calibration. In this experiment, we used a CR1000 datalogger to collect TDR measurements and to control a linear micro-step actuator. This experiment was carried out in both deionized water and oil, representing high and low permittivity conditions, respectively. Our preliminary results showed that fringing field diameter is largest in the direction parallel to the rods. In addition, the minimum diameter of a calibration cell for the TDR315N is 56 mm.
Determining Sensing Area of Electromagnetic (EM) -Based Sensors
Logan, UT
Electromagnetic (EM) -based sensors are the most popular soil moisture sensors used globally. However, the accuracy of sensors may be altered by aging, and calibrations may be soil-specific. Therefore, sensor calibration is an important issue. Previous research has studied calibration of EM sensors using mixed testing approaches with mixed results. Unfortunately, sensor calibration may be complicated and calibration methods may need to be improved. The objectives of this research are (1) to establish a general framework for calibrating electromagnetic (EM) -based sensors from different manufacturers, and (2) to determine the sensing area of a time-domain reflectometry (TDR) sensor in order to size the calibration cell. Sensing area is the region in which the sensor can detect a change in water content. Determining the sampling volume of sensors being used is important to understand prior to calibration. In this experiment, we used a CR1000 datalogger to collect TDR measurements and to control a linear micro-step actuator. This experiment was carried out in both deionized water and oil, representing high and low permittivity conditions, respectively. Our preliminary results showed that fringing field diameter is largest in the direction parallel to the rods. In addition, the minimum diameter of a calibration cell for the TDR315N is 56 mm.