sensor is wired to. Besides the analog input, be sure to wire up the sensor to the
ground and to switched battery.
No other setting needs to be setup. Please be aware that it takes up to 20 seconds
to complete a soil measurement.
When measuring soil sensors, MONITOR will first ensure that the sensor has
been powered down for at least 10 seconds. It will then power the sensor for one
second and collect multiple samples for 300ms. It will average those samples into
voltage V1. MONITOR will then wait until 8 seconds have passed since the
sensor was powered on. It will then collect samples for about 300ms and average
them out into reading V2. MONITOR uses the following equations to compute
the results:
Soil moisture:
D = 1/(V2-V1)
Moisture = -0.076 + 0.135*D - 0.01145*D
2
+ 0.0003363*D
3
Soil conductivity:
X = log(V2-V1)
Conductivity = 10^(-.284 – 1.334*X - 0.573*X^2 - 0.136 * X^3)
Soil temperature:
Temperature Fahrenheit = -45.11 + 282.8*V1
Please note that you do
not
need to enter these equations into monitor. Simply
setup the measurement type as
Soil
and choose the appropriate
Soil Type.
MONITOR will do the rest.
Please note that the soil temperature reading will be in Fahrenheit. To convert to
Celsius, set the slope to 0.555556 and the offset to -17.77778 or use equation (X-
32.0)*5/9.
If details are turned on for soil sensors, the minimum is not really a minimum but
voltage V1 (see above), and the maximum is voltage V2.
The
Averaging Time
field is not available for soil sensors. In order to get the
average of soil measurements, two measurements will need to be setup: soil and
meta. The example below shows how to get the four hour average while
measuring the soil sensor every 15 minutes.
Measurement M1
(used for soil)
Measurement Type:
Soil
Measurement Interval:
00:15:00
Measurement M2
(used for averaging soil)
Measurement Type:
Meta
Meta Index:
1 (meaning it refers to measurement M1)
Measurement Interval:
04:00:00
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