Decagon Devices EC-20 User Manual

EC-20, EC-10 and EC-5 User’s Manual
4. Collecting Data
18
ø = 11.9 * 10
-4
* mV - 0.401 (2)
where mV is the output of the sensor when excited at
2500 mV. Please note that the equation will reach a
maximum at ~60% volumetric water content (VWC) in
pure water. To display data on a scale from 0 to 100%,
VWC should be modeled with a quadratic equation
(which would result in a 100% VWC in water), but a
linear equation fits the mineral soil VWC range as well
as the quadratic, and linear equations are easier to deal
with, especially since mineral soil typically saturates at
~40 - 50% VWC.
Potting soil
The following equations can be used to convert EC-5
output to water content in potting soil. We tested several
types of potting soil (Sunshine mix, Miracle Grow Pot-
ting Mix, and Custom Nursery soil) at several salinities
and found that VWC is given by
ø = 1.3 * 10
-3
* Raw - 0.696 (3)
for a Decagon datalogger or
ø = 2.11 * 10
-3
* mV - 0.675 (4)
for a datalogger with 2500mV excitation.
Rockwool
The EC-5 was calibrated in Grodan Master rockwool
with solution electrical conductivities of 0.2, 1.0, 1.5,
2.0, and 4.5 dS/m. Volumetric water content can be cal-
culated using

Decagon Devices EC-20 Specifications

General

Brand	Decagon Devices
Model	EC-20
Category	Accessories
Language	English