Soil - Moisture

MAS-1 4-20 milliamp water content sensor

The MAS-1 4-20 milliamp sensor accurately measures water content with a standard 4-20 milliamp output. This sensor is best for industrial systems or systems where a sensor with 250 feet of cable or greater is required

4-20 Milliamp Output, Ultra-Long Cable Lengths

The MAS-1 4-20 milliamp sensor is the primary current-based sensor to use Decagon's unique 70 MHz technology. This sensor provides a standard 4-20 milliamp output that is expected with PLCs and irrigation controllers. With the 4-20 mA interface, cable lengths exceeding 250 feet are possible.

Research Grade Accuracy

Like alternative Decagon soil moisture sensors, the MAS-1 measures soil moisture precisely without the sensitivity to electrical conductivity and variation in soil types that have hindered previous cost efficient sensors. The MAS-1 delivers lab grade accuracy at a price that makes large sensor networks economically viable. You can sufficiently fill your land with sensors at varying depths and locations, even if you're on a restricting budget. And the MAS-1's extended cable lengths give you yet more flexibility to put your sensors wherever you want.

Engineered for Accuracy

The MAS-1 calculates volumetric water content (VWC ) by analysing the dielectric constant of the substrate using capacitance/frequency domain technology. The sensor utilises a 70 MHz frequency, which reducse salinity and textural influence, making the MAS-1 precise in most soil types and soil-less media. Factory calibrations are available for mineral soils, potting soils, and rockwool.

Reasons to pick the MAS-1

  • If you need a 4-20 milliamp sensor
  • If you need cable lengths greater than 250 feet
  • Low cost, accurate and reliable 4-20 milliamp (mA) sensor
  • Measure calibrated soil volumetric water content or moisture
  • Ideal for soils or substrates in the field, glasshouse, pots, or laboratory
  • Manufactured by METER Group (formally Decagon Devices)

4-20 mA (current, milliamp)
power input
12-32 VDC continuous
over protection
settling time
4 seconds
Red Wire: (+) supply Black Wire: (-) output Shield: not connected
sensor type
volumetric water content
measurement range
0-100% VWC typical
depends on current measurement (data acquisition) device
±6% VWC with generic calibration for supported growing media up to 65% VWC, above which accuracy lessens. Increased accuracy can be achieved with a medium-specific calibration.
sensor measurement interval
1 second
operating temperature
-40 to 60 °C
8.9 cm x 1.8 cm x 0.7 cm
5 m (default) | other lengths available upon request

The MAS-1 is a low cost, ruggedized sensor for the measure of soil volumetric water content with a current, 4-20 mA (milliamp) output. The MAS-1 can accurately measure the moisture content in soil or soilless media.

The MAS-1 is ideal for scientific researchers, growers, nurseries, and glasshouses with pots or artificial substrates. The robust sensor design, plus flexible output to connect to most data loggers or systems, makes the MAS-1 ideal for monitoring water content.


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