Pr
o
Minent
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Page 86
Inductive Conductivity
Set the temperature coeffi cient
of the water sample in the “meas. parameter setting?” setting
menu (related to 25 °C. Arrow keys!)
Set the temperature coeffi cient
of the water sample at the reference metering equipment (to
the same value)
calibration cc
probe in buffer1!
accept value?
1538
μ
S/cm 1.23
calibration cc
PAR 1
please wait!
cc calibration
cc: 1.23 /cm
calibration cc
cc: 1.23 /cm
LF: 1500
μ
S/cm
= automatic timing
Select the fi rst menu option in the “calibration cc” setting menu and press Enter
the temperature of the water sample must remain constant within ±0.5 °C for 20 min. and the
measured conductivity value must not fl uctuate
Remove a sample from the water and determine the electrolytic conductivity using reference
metering equipment (stir for 30 s with its sensor)
Enter the measured conductivity reference value in the second menu option under “LF” (arrow
keys!) and press Enter
“please wait” is displayed for a few seconds. The DULCOMETER
®
D1C then displays the current
calculated cell constant.
The new cell constant is accepted when you press Enter to exit the last menu option (“cal i bra-
tion cc - cc = ...”). If you do not want to accept the new cell constant, exit this menu option with
the back key.
Calibration with Calibration Solution
Important precondition: You need a calibration solution of the corresponding accuracy (better
than 1 % absolute reproducibility; at least 500 ml).
CAUTION
Take the necessary precautions when dismantling the sensors (safety gear...)!
IMPORTANT
• Handle the calibration solution with extreme care. Adequate accuracy will not otherwise
be achieved.
• Ensure cleanliness and avoid carry-over or evaporation of the liquid (evaporation even
after 20 min. can be too much).
Dismantle the sensor from the tubing
Wipe deposits off the sensor and rinse
then rinse the sensor with deionised water until the displayed conductivity value is less than
20 μS/cm
Dry the sensor thoroughly (including inside the bore of the sensor tip)
Place the sensor in a clean standard glass beaker along with the calibration solution
Stir with the sensor until the air bubbles have been expelled from the bore and the displayed
conductivity value on the DULCOMETER
®
D1C is stable
Fix the sensor in the centre of the beaker so that the sensor tip is at least 30 mm from the
glass in all directions (preferably 40 mm). The sensor tip must be immersed at least 30 mm
(top edge of sensor tip)
Wait 20 min. until the temperature has equalised between the sensor and calibration solution
(1 °C temperature deviation equals approx. 2 % measurement error)
Set the temperature coeffi cient
at the DULCOMETER
®
D1C to the value specifi ed by the
manufacturer for the calibration solution (e.g. approx. 1.86 %/K for KCI solutions around 25 °C)
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24.02.2009 11:56:08 Uhr
24.02.2009 11:56:08 Uhr