ProMinent DULCOTEST Montage- Und Betriebsanleitung Seite 59

4. Determine the conductivity of the
sample water with the reference
instrument and enter the estab‐
lished value as per the operating
instructions for that controller
High measurement accuracy/calibrate
with calibration solution
Important prerequisite: A calibra‐
tion solution of the appropriate pre‐
cision should be available (better
than 1% absolute precision; at
least 1000 ml).
Be extremely cautious with the cal‐
ibration solution otherwise you will
not achieve sufficient precision.
Pay attention to cleanliness and
avoid displacement or evaporation
of the liquid, after 20 minutes too
much may have already evapo‐
rated.
In order to ensure that the conduc‐
tivity of the calibration solution
hasn't changed due to displace‐
ment or evaporation, it is strongly
recommended that the conductivity
of the calibration solution is
checked with an appropriate refer‐
ence instrument.
5. Dismantle the sensor
6. Wipe deposits from the sensor and
rinse off the sensor
7. Rinse the sensor with di-water until
the conductivity value displayed is
less than 20 μS/cm
8. Dry the sensor completely,
including inside the sensor head
hole
9. Put the sensor in a clean standard
beaker with the calibration solution
10. Swirl the sensor until all the air bub‐
bles have come out of the hole and
the displayed conductivity value on
the controller is stable
11. Fix the sensor in the centre of the
beaker so that in all directions the
sensor is at least 10 mm away from
the glass (20 mm is better). The
sensor head must be submerged to
at least 10 mm (top of the sensor
head).
12. Wait for 20 minutes until there is a
temperature compensation between
the sensor and the calibration solu‐
tion. 1 °C temperature deviation is
equivalent to a measurement error
of around 2%
13. Set the temperature coefficient α on
the controller to the value given by
the manufacturer of the calibration
solution, e.g. approx. 1.86%/K for
KCl solutions at 25 °C
14. Align the sensor as described in the
operating instructions for the con‐
troller you are using
Start up
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