TDR Soil Moisture Sensor, RS485 Output

High-quality TDR soil moisture sensor using time domain reflectometry, capable of accurately measuring volumetric water content ranging from 0 to 60% m³/m³, with a resolution of 0.1% and measurement accuracy within ±3%. The TDR moisture sensor supports RS485 Modbus-RTU output, operates at a voltage of 12–24 VDC, and has a typical current of 50 mA at 12V. With an IP68 waterproof rating, an ABS housing, and a 316 stainless steel TDR moisture probe, this sensor ensures reliable long-term soil monitoring for users.

Feature

• Measure the volumetric water content of soil within a 10 cm radius around the soil moisture sensor probe.
• Low temperature drift and wide range of soil types.
• IP68 protection rating, suitable for long-term burial in soil.
• Non-linear correction, high accuracy, lightning protection, and strong anti-interference capability.
• TDR soil moisture sensors are small, lightweight, and easy to install.

Dimension (unit: mm)

Wiring

Important Notes

• Before measurement, select soil with uniform density as the test object.
• Do not insert the soil moisture sensor probe into hard soil clumps to prevent damage to the probe.
• Do not pull the cable directly to remove the sensor from the soil. Instead, hold the probe housing with your hand and pull the sensor out.
• After use, brush off any soil dust from the probe and wipe the soil moisture sensor probe dry with a soft cloth to keep the probe clean and extend its service life.

Installation and Measurement

1. Based on the above principles, the accurate installation method for soil moisture sensors can be referenced using the following basic steps to achieve high-quality installation (as shown in the figure above):
2. First, dig a hole to ensure that the soil remains undisturbed in the vertical direction of the slope.
3. At the installation depth, scrape away part of the vertical soil surface to ensure the undisturbed soil surface is level. Insert the soil moisture sensor vertically into the undisturbed soil at the installation depth, ensuring it is inserted vertically. Continue inserting until the entire sensor is fully inserted (including the sensor tail). Each sensor probe is sharpened; please ensure safety!  
4. After connecting the data logger for calibration, backfill the soil pit once the readings are normal, ensuring the backfilled soil's bulk density matches the surrounding soil. For deep soil burial, layered backfilling is required, i.e., filling in layers.
5. After installing the sensor, the soil sensor's quick-connect interface allows the cable length to be customized according to on-site application needs (standard cable length is 5 meters). To enhance data transmission stability, it is recommended that the customer-defined cable length does not exceed 1 kilometer.