SM150T User Manual 1.0
Operation
20
Use of polynomial equation to calculates soil moisture
To convert the SM150T output to soil moisture
1) Convert Volts V to
using the following equation
= 1 + 14.4396 V − 31.2587V
2
+ 49.0575V
3
− 36.5575V
4
+ 10.7117V
5
Where V is the SM150T soil moisture output converted from milliVolts to
Volts.
2) Convert the
√ε
value to soil
moisture
θ
using
θ = (√ε − a
0
)/a
1
Where
a0 and a1 are constants
:-
For temperature measurement see page 50
a
0
a
1
Mineral
1.6
8.4
Organic
1.3
7.7
Peat mix
1.16
7.09
Coir
1.16
7.41
Min. wool
1.04
7.58
Perlite
1.06
6.53
