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HD3910 – Soil Volumetric Water Content
Brand: Delta OHM S.R.L.
The probes HD3910.1 (two electrodes) and HD3910.2 (three electrodes) measure the soil volumetric water content (VWC) by using a capacitive measurement principle which allows fast measurements in the field and with minimal invasiveness.
The three-electrode probe HD3910.2 is particularly suitable for the measurement in small volumes, for example for cultivations in pots. The probes are factory-calibrated and do not require any further calibration by the end user.
The circuit board is protected inside a housing made of plastic material and sealed with epoxy resin which allows achieving reliable measurements even in harsh environmental conditions.
The version with RS485 digital output with MODBUS-RTU protocol allows the use of even very long connection cables. It can be connected to the data loggers HD32MT.1 and HD32MT.3 or to any other data logger with RS485 MODBUS-RTU input.
The version with SDI-12 digital output is compatible with version 1.3 of the protocol and can be connected to the data logger HD32MT.3 or to any other data logger with SDI-12 input.
The version with analog output has two 0.5 to 3 V standard voltage outputs: one for the volumetric water content and one for the temperature. On request, 0 to 2.5 V, 0 to 5 V or 0 to 10 V outputs.
The probes are equipped with a fixed cable, 5 or 10m standard length, with open wires at the end.
Features- Measurement of the soil volumetric water content with 2 electrodes (HD3910.1) or 3 electrodes (HD3910.2) for restricted volumes
- Measurement of the soil temperature
- Various output options available (depending on model): digital RS485 with MODBUS-RTU protocol, digital SDI-12 or analog voltage
- Accurate and stable measure over time
- Degree of protection IP 67
- Minimal invasiveness in the soil
- Easy to install
Specifications
Brand
Volumetric Water Content Measuring Principle
- Capacitive
Volumetric Water Content Measuring Range
- 0 to 60 % VWC
Volumetric Water Content Resolution
- 0.1%
Volumetric Water Content Accuracy (@ 23° C)
- ± 3 % between 0 and 50 % VWC
- Standard mineral soil, EC < 5 mS/cm)
Volumetric Water Content Measuring Volume
- ∅= 100 mm x H=150 mm for the 2-electrode probe
- ∅= 80 mm x H=110 mm for the 3-electrode probe
Volumetric Water Content Sensor Operating Temperature
- -40° to +60° C
Temperature Sensor
- NTC 10 kΩ @ 25° C
Temperature Measuring Range
- -40° to +60° C
Temperature Resolution
- 0.1° C
Temperature Accuracy
- ± 0.5° C
Temperature Long-Term Stability
- 0.1° C / year
Power Supply
- 3.6 to 30 Vdc for versions with 0 to 2.5 V analog output
- 5 to 30 Vdc for versions with RS-485 output and versions with 0.5 to 3 V analog output
- 6 to 30 Vdc for versions with SDI-12 output
- 7 to 30 Vdc for versions with 0 to 5 V analog output
- 12 to 30 Vdc for versions with 0 to 10 V analog output
Consumption
- Versions with RS-485 output: 2 mA average / 15 mA peak @ 12 Vdc
- Versions with analog output: 2.5 mA average / 15 mA peak @ 12 Vdc
- Versions with SDI-12 output: 300 µA @ 12 Vdc in standby, < 15 mA @ 12 Vdc during measurement
Output
- RS-485 with Modbus-RTU protocol
- SDI-12
- 0.5 to 3 V analog voltage (0.5 V=0 %VWC or -40° C , 3 V=60 %VWC or +60° C, minimum load resistence 10 kΩ)
Materials
- Handle: thermoplastic material and epoxy resin
- Electrodes: epoxy glass, thickness 2 mm
Connection
- Fixed cable with open wires at the end, length 5 or 10 m standard
Protection Degree
- IP 67
Weight
- 150 g approx. (including the 5 m cable)
