Soil Moisture Calibration - Ambient Weather Copyright 2019 User Manual

6.7.19 Soil Moisture Calibration

The soil moisture sensor provides for optional two point linear calibration. This is important due to
different soil types and density.
The calibration equation is defined as:
% Soild Moisture (calibrated) = ( Now AD – 0%AD) *100 / (100%AD – 0%AD)
Where AD stands for "analog to digital" and is the unscaled digital value, Now AD is the currently
measured AD and the other parameters are described below.
6.7.19.1 0% Soil Moisture Set Point
To determine the 0% soil moisture, collect a soil sample in a cup from where the sensor will be
installed, and allow the soil to completely dry out. Next, place the soil sensor in the medium and
allow the sensor to stabilize for one hour.
Next, set the 0%AD calibration set point to the Now AD value.
6.7.19.2 100% Soil Moisture Set Point
To determine the 100% soil moisture, collect a soil sample in a cup from where the sensor will be
installed, and add water and mix until the soil is saturated, and there is no standing water. Next,
place the soil sensor in the medium and allow the sensor to stabilize for one hour.
Next, set the 100%AD calibration set point to the Now AD value.
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