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Enabling better global research outcomes in soil, plant & environmental monitoring.

Decagon MAS-1 4-20mA

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

ELECTRICAL

INTERFACE Standard 4-20 mA analogue transmitter
SUPPLY VOLTAGE 12-32 VDC continuous
OUTPUT CURRENT 4 – 20 mA
OVERVOLTAGE PROTECTION Yes
SETTLING TIME 4 seconds
WIRING Red Wire: (+) supply
Black Wire: (-) output
Shield: not connected

MEASUREMENT

TYPE Volumetric water content (VWC)
RANGE 0-100% VWC typical
RESOLUTION Depends on current measurement (data acquisition) device
ACCURACY ±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.
OUTPUT 4-20 mA current proportional to VWC
SENSOR MEASUREMENT INTERVAL 1 second
OPERATING ENVIRONMENT TEMPERATURE -40 to 80°C
PHYSICAL PROPERTIES DIMENSIONS 8.9 cm x 1.8 cm x 0.7 cm
CABLE 2m or 5m, 3 wire (22 AWG tinned Red and Black wire, 24 AWG tinned bare wire); custom cable length available upon request.

Research Grade Accuracy

Like other Decagon soil moisture sensors, the MAS-1 measures soil moisture accurately without the sensitivity to electrical conductivity and variation in soil types that have plagued inexpensive sensors in the past.

The MAS-1 delivers research-grade accuracy at a price that makes large sensor networks economically practical. You can adequately characterise your site with sensors at multiple depths and locations, even if you’re on a tight budget. And the MAS-1’s ultra-long cable lengths give you even more flexibility to put your sensors where you want them.

Engineered for Accuracy

The MAS-1 determines volumetric water content (VWC ) by measuring the dielectric constant of the media using capacitance/frequency domain technology. The sensor uses a 70 MHz frequency,  which minimises salinity and textural effects, making the MAS-1 accurate in almost any soil or soil-less media. Factory calibrations are included 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