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ECH2O TE Soil Moisture, Conductivity, Temperature
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ECH2O-TE 3-prong design, measures soil moisture, electrical conductivity, and temperature
ECH2O-TE 3-prong design, measures soil moisture, electrical conductivity, and temperature. By design, salinity effects on moisture content values are greatly minimized.The ECH2O TE is our revolutionary new ECH2O probe, designed to measure soil moisture, electrical conductivity (EC), and temperature simultaneously. Like the EC-5, it operates at a higher frequency (70Hz), giving it a very low sensitivity to changes in EC, making it ideal for greenhouses or saline soils.
Product Description
The ECH2O TE uses an oscillator running at 70MHz to measure the dielectric permittivity of the soil to determine the water content. A thermistor in thermal contact with the probe measures the temperature, while the gold traces on the surface of the sensor form a four-pole array to measure electrical conductivity.
VOLUMETRIC WATER CONTENT
The ECH2O - TE uses an electromagnetic field to measure the volumetric water content of the surrounding medium. The probe supplies a 70 MHz oscillating wave to the probe prongs that charges according to the dielectric of the material. The stored charge is proportional to soil dielectric and soil volumetric water content. The ECH2O - TE microprocessor measures the charge and outputs a value from the probe, which is correlated with water content.
ELECTRICAL CONDUCTIVITY
Electrical conductivity (EC) is measured by applying an alternating electrical current to two outer electrodes, and measuring the voltage between two inner ones. Both this voltage and the current are used to determine conductance. Conductivity is then derived by multiplying voltage and conductance by the cell constant (the ratio of the distance of the electrodes to their area). The ECH2O TE uses a Wenner Array to measure the EC. The Wenner Array is located on the four strips of gold on two of the ECH2O TE prongs.
TEMPERATURE
The ECH2O TE uses a surface-mounted thermistor to take temperature readings. The thermistor is in thermal contact with one of the probe prongs and will read an average temperature along the prong surface.
The ECH2O TE connects to the Em50 loggers, and gives a serial digital output.
Specifications
DIMENSIONS: 10cm (l) x 3.2cm (w) x 0.7cm (d)
PRONG LENGTH: 5.2 cm
POWER REQUIREMENT: 3VDC, 0.3 mA quiescent, 10 mA for 9 ms measurement
VOLUMETRIC WATER CONTENT:
RANGE: 0 100% VWC
FREQUENCY: 70MHz
RESOLUTION: 0.1% VWC (mineral soil), 0.25% VWC (rockwool)
ACCURACY:
MINERAL SOIL : +/-4% VWC up to 8 dS/m, +/- 2% VWC with soil-specific calibration.
ROCKWOOL +/-3% VWC, 0.5 to 8 dS/m
POTTING SOIL +/-3% VWC, 3 to 14 dS/m
TEMPERATURE:
RANGE: -40 to +50c
RESOLUTION: 0.1c
ACCURACY: +/-1c (0 to 50c)
ELECTRICAL CONDUCTIVITY:
RANGE: 0 to 15 dS/m (solution)
RESOLUTION: 0.01 dS/m
ACCURACY: +/-10%
OUTPUT 3.5 mm stereo plug (RS-232)
COMPATIBILITY Em50 Datalogger, CSI datalogger digital I/O
CALIBRATION: Mineral soil, rockwool, and potting supplied in DataTrac. User-defined options also available.