Geoves

Description

MEASURING PRINCIPLE AND FEATURES

The probe measures the dielectric constant of the soil in order to find its volumetric water content. Since the dielectric constant of water is much higher than that of air or soil minerals, the dielectric constant of the soil is a sensitive measure of water content. The RHT sensor supplies a 70 MHz oscillating wave to the sensor prongs that induces an electromagnetic field in the medium (soil) surrounding the sensor. The charging and discharging of the sensor is controlled by the dielectric of the surrounding soil.

A microprocessor on the sensor measures the charging of the sensor, and therefore the dielectric constant of the soil which is related to the water content of the soil. The microprocessor makes a dielectric measurement and updates the transmitted current once per second. The transmitted 4-20 mA current can be converted to the water content of the soil using a simple calibration function. The RHT was designed to be used with standard 4-20 mA controllers and monitoring systems

ADVANTAGES

• High accuracy
• Suitable for the main applications
• No maintenance and long lifetime 
• Low time of response