Campbell TDR Manual Pagina 23

  • Descarga
  • Añadir a mis manuales
  • Imprimir
  • Pagina
    / 28
  • Tabla de contenidos
  • MARCADORES
  • Valorado. / 5. Basado en revisión del cliente
Vista de pagina 22
Appendix B. Correcting Electrical Conductivity Measurements for System Losses
The temperature effect is described by:
(
)
(
)
25T02.01ECEC
25T
+
=
[B4]
where is the electrical conductivity at 25
ºC and is the electrical
conductivity at other temperatures.
25
EC
T
EC
B.2.3 Deriving Calibration Function
Using the K
p
, ρ
open
and ρ
shorted
values for each probe, the uncorrected electrical
conductivity as measured by the TDR100 can be corrected to give accurate EC
values that account for system losses. To do this, a range of EC values is
chosen for σ
uncorrected
in equation [B5] and σ
corrected
values calculated for the
chosen range of σ
uncorrected
.
()
puduncorrectepshorteduduncorrecteshortedu
pairuduncorrecteairpuduncorrecte
pcorrected
KZKZZ
KZKZ
K
σ+ρ+σρ
ρ
+
σ
ρ
+
σ
=σ [B5]
This equation has a quadratic form. The correction is easier to use if a curve is
fit to the σ
corrected
values for the chosen range of σ
uncorrected.
This quadratic is
implemented in the datalogger program to given the final result that is
corrected electrical conductivity. This must be done for each probe.
0 0.75 1.5
0
0.75
1.5
uncorrected EC (siemen/meter)
corrected EC (siemen/meter)
FIGURE B-1. Example of corrected and uncorrected electrical
conductivity values.
The fitted equation for this probe is
2
duncorrecteduncorrectecorrected
35.095.001.0 σ+σ+=σ
B-3
Vista de pagina 22
1 2 ... 18 19 20 21 22 23 24 25 26 27 28

Comentarios a estos manuales

Sin comentarios