6
CALIBRATION
10HS
6
Calibration
6.1
Dielectric calibration
The 10HS comes pre-calibrated to measure the dielectric permittivity
of the soil with the accuracy stated in the specification section above.
With Decagon’s Em50, Em50R, Em5B, and Pro Check readers, the
following standard calibration function can be applied
ε
a
= 7
.
449 x 10
−
11
∗
raw counts
4
−
1
.
969 x 10
−
7
∗
raw counts
3
+
1
.
890 x 10
−
4
∗
raw counts
2
−
6
.
691 x 10
−
2
∗
raw 7
.
457
(3)
With non-Decagon data acquisition equipment, the following cali-
bration can be applied. Note the this calibration function is valid for
any sensor excitation between 3 and 15 V DC.
ε
a
= 2
.
589 x 10
−
10
∗
mV
4
x
−
5
.
010 x 10
−
7
∗
mV
3
+
3
.
523 x 10
−
4
∗
mV
2
−
9
.
135 x 10
−
2
∗
mV
+ 7
.
457
(4)
6.2
Mineral Soil Calibration
For convenience, Decagon has also developed a standard calibration
equation for mineral soils to be used with the 10HS. With this stan-
dard calibration equation and careful sensor installation, accuracy of
better than
±
3% VWC (0.03 m
3
/m
3
) is possible with most mineral
soils. In these soils , it is generally not necessary to calibrate the
10HS for your particular soil type, and the standard mineral calibra-
tion below can be used. Em50, Em50R, Em5B and ProCheck:
V W C
(
m
3
/m
3
) = 1
.
17 x 10
−
9
∗
raw counts
3
−
3
.
95 x 10
−
6
∗
raw counts
2
+ 4
.
90 x 10
−
3
∗
raw counts
−
1
.
9
(5)
With non-Decagon data acqusition equipment, the following calibra-
tion can be applied. Note that this calibration function is valid for
12
