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MAS-1 4-20 Milliamp Soil Moisture Sensor

Updated:2025-03-13

Brand: METER
Model: MAS-1
Description: The MAS-1 4-20 milliamp soil moisture sensor is the first current-based sensor to use METER’s trademark 70 MHz technology. This sensor offers a standard 4-20 milliamp output that is common with PLCs a
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MAS-1 4-20 Milliamp Soil Moisture Sensor Description：

User's Manual

? Affordable current-based soil moisture sensor

The MAS-1 4-20 milliamp soil moisture sensor is the first current-based sensor to use METER’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.

? Research-grade accuracy

The MAS-1 soil moisture sensor 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 minimizes 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.

? Low cost individual sensors for large sensor networks

The MAS-1 delivers research-grade soil moisture accuracy at a price that makes large sensor networks economically practical. You can adequately characterize your site with sensors at multiple depths and locations, even if you’re on a tight budget.

MAS-1 4-20 Milliamp Soil Moisture Sensor Specification：

Interface：	Standard4-20mAanalog transmitter NOTE: Temperature measurement may notbeaccurate if sensor is not fully immersed in the medium of interest. due to excessively long equilibration time.
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
Sensor 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 60°C NOTE:Sensors can be used at higher temperatures under some conditions. Contact METER for more details.
Physical properties dimensions：	8.9 cm x 1.8 cm x 0.7 cm
Cable：	2mor5m.3 wire (22 AWG tinned red and black wire, 24 AWG tinned bare wire); custom cable length available upon request.
Measurement volume：	See comparison article