SM150T User Manual 1.0
Operation
28
Linearisation table
(for use over the full range of SM150T readings)
V
V
V
V
V
0.000
1.000
0.300
3.576
0.600
5.101
0.900
6.778
1.200
8.924
0.075
1.942
0.375
3.964
0.675
5.503
0.975
7.232
1.275
9.743
0.150
2.620
0.450
4.337
0.750
5.917
1.050
7.720
1.350 10.808
0.225
3.144
0.525
4.713
0.825
6.342
1.125
8.270
1.425 12.242
Soil moisture reading
Polynomial conversion
Combining the
Soil calibrations
and
Sensor calibration
steps, the conversion equation becomes:
𝜃 =
[1.0 + 14.4396𝑉 − 31.2587𝑉
2
+ 49.0575𝑉
3
− 36.5575𝑉
4
+ 10.7117𝑉
5
] − 𝑎
0
𝑎
1
where
a
0
and
a
1
are the calibration coefficients
For a generalised
mineral
soil this becomes:
𝜽
𝒎𝒊𝒏𝒆𝒓𝒂𝒍
= −0.0714 + 1.7190𝑉 − 3.7213𝑉
2
+ 5.8402𝑉
3
− 4.3521𝑉
4
+ 1.2752𝑉
5
And for a generalised
organic
soil:
𝜽
𝒐𝒓𝒈𝒂𝒏𝒊𝒄
= −0.0390 + 1.8753𝑉 − 4.0596𝑉
2
+ 6.3711𝑉
3
− 4.7477𝑉
4
+ 1.3911𝑉
5
