Jingli Keanley KLS-3150 Soil Moisture/Temperature/Conductivity sensor

Beijing Jingli KLS-3150 Soil Multi-Parameter Sensor Introduction

KLS-3150 User Manual

The KLS-3150 produced by Beijing Jingli is an integrated sensor that combines the measurement functions of three key parameters: soil volumetric water content, temperature, and volumetric electrical conductivity. It is designed to provide long-term, stable, and reliable in-situ soil data for agriculture, environmental monitoring, and scientific research.

1. Core Functions and Measurement Principles

The core technology of this sensor is based on the dielectric impedance measurement method. Unlike traditional TDR or ordinary capacitive sensors, it uses high-frequency radio frequency signals (operating at 70MHz) to accurately determine the soil's apparent dielectric constant by analyzing the energy storage (real part of the dielectric constant) and energy loss (imaginary part of the dielectric constant) characteristics of electromagnetic waves propagating in the soil medium. This method effectively isolates interference from factors such as salt content, soil texture, and temperature on moisture measurement, thereby improving the accuracy of core parameter measurements.

Volumetric Water Content Measurement: The sensor transmits a high-frequency oscillating wave to the probe. Its charging time is proportional to the dielectric constant of the surrounding medium. Since the dielectric constant of water is much higher than that of other components in the soil, changes in the dielectric constant directly reflect changes in soil water content. The built-in microprocessor converts the measured raw dielectric value into a volumetric water content value using specific calibration equations.

Temperature Measurement: A small thermistor integrated on the PCB and close to the probe root is used for measurement. This design optimizes the thermal response speed and accuracy of the sensor when fully buried, enabling it to quickly track changes in soil temperature.

Volumetric Electrical Conductivity Measurement: The volumetric electrical conductivity of the soil is calculated by applying an alternating current to the sensor electrodes, measuring the resistance between them, and combining this with the cell constant of the electrodes. This parameter can be used to assess salt content and ion concentration in the soil.

2. Soil Sensor Specifications

3. Physical Structure and Installation Design

Structure and Dimensions: The sensor body is compact, with a probe length of less than 5 cm, facilitating installation and minimizing disturbance to the soil structure.

Material and Protection: The sensor body is encapsulated in rugged epoxy resin, capable of withstanding harsh field environments and ensuring long-term physical and chemical stability.

Anti-Interference Design: A ferrite core is integrated inside the cable, effectively suppressing external electromagnetic noise introduced by the cable and ensuring signal purity.

Cable and Connection: Standard configuration includes a 5-meter long cable with a 3-pin plug connector for easy connection to data loggers.

4. Technical Advantages and Reliability

Through precise manufacturing processes and digital signal processing technology, this sensor significantly reduces measurement variation between individual sensor units, achieving excellent interchangeability. Users do not need to perform separate calibrations for each sensor. Furthermore, the product supports field verification using independent precision verification standards. Users can periodically verify and confirm whether the sensor performance is within the specified range. This feature provides crucial assurance for the long-term credibility of the data. Its robust design and optimized measurement algorithms collectively ensure stable operation for several years under complex field conditions.