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