Umwelt-Geräte-Technik GmbH
| Eberswalder Str. 58 | D-15374 Müncheberg | phone: +49 (0) 33 43 2 - 89 575 |
Under the assumption that C
T
did not change, the estimation of the
new
P
0
is done as follows:
𝑃
0
=
𝑃
𝑟𝑒𝑓20°𝐶
− (20 °𝐶)
2
∙ 𝐶
𝑇1
− 20 °𝐶 ∙ 𝐶
𝑇2
p
ref,20
°
C
… measured maximal pressure at 20
°
C [kPa]
C
T1
… temperature coeffiecient [kPa/
°
C
2
]
, see calibration certificate
C
T2
… temperature coeffiecient [kPa/
°
C]
, see calibration certificate
Use the
new
P
0
value
for all further readings and calculations.
𝑝
𝑟𝑒𝑓
= 𝐶
𝑇1
∙ 𝑇
𝑐𝑢𝑟𝑟𝑒𝑛𝑡
2
+ 𝐶
𝑇2
∙ 𝑇
𝑐𝑢𝑟𝑟𝑒𝑛𝑡
+
𝑃
0
𝛹 = 𝑝
𝑟𝑒𝑓
− 𝑝
𝑐𝑢𝑟𝑟𝑒𝑛𝑡
Further, a simplified calibration with a parallel conventional tensiometer at the measurement site is
possible. For this the offset between the Full Range Tensiometer and the conventional tensiometer is
determined and subtracted from the reference pressure.
To ensure the correct function of the tensiometer a complete check-up and maintenance by UGT GmbH
in a yearly interval is recommended.
Note:
P
0
won’t be saved on the FRT itself.
P
0
has to be noted in the datalogger or the FRT-Log software,
since P
ref
and Ψ are also calculated after colle
cting the pressure and temperature readings from
the FRT.
(2)
(1)