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Setting the zero point
The pressure sensors built into the logger unit can be calibrated by the user. It may
be necessary to recalibrate the pressure sensors, for example after maintenance
work, if the measurement set-up is changed, or after the measuring station has
been operated for a year or more.
Calibration is carried out with the Logger 5 software.
Recommended interval between calibrations: 1–2 years.
When carrying out a calibration, note that the sensors must be checked/calibrated
in the same positions as they occupy in the measuring point (usually upright) and
they must be positioned next to each other at the same level.
Testing by the manufacturer
The DCX may also be sent to KELLER AG für Druckmesstechnik in order to
verify its measurement accuracy or for calibration. The following test options may
be chosen: simple check on the DCX without documentation, internal check with
documentation (5- or 11-point test protocol) or an internal check followed by ex
-
ternal certification (DKD [German Calibration Service] or SCS [Swiss Calibration
Service] calibration certificate).
(Charges are payable for checks/verifications, calibrations, protocols and certifi
-
cates)
Calibration
Series DCX devices measure and store the hydrostatic pressure of a fluid in bar.
The density of the medium has a decisive influence on the conversion of the pres
-
sure [bar] to the water column level [mWS]. The height of the water column is
calculated with the following formula in the Logger 5 software:
P = hydrostatic pressure (0,1 bar = 10’
000 N/m
2
)
ρ = water density (kg/m
3
) = 998,207 kg/m
3
@ 20°C
g = gravitational acceleration (= 9,80665 m/s
2
)
h = height of water column (m)
Level measurement with pressure sensors
Data logger
Plug for converter
cable
h =
p
=
10000 N/m
2
=
1,021 mWS
ρ
*
g 998,207 kg/m
3
*
9,80 m/s
2
