wtw inoLab 740, Руководство по эксплуатации

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Conductivity
182
10.2 Determining/setting up the cell constant
Why determine/set
up the cell
constant?
Aging slightly changes the characteristics of the cell, e. g. by
coatings. As a result, an inexact measured value is
displayed. The original characteristics of the cell can often
be restored by cleaning the cell. Calibration determines the
current cell constant and stores it in the instrument.
Thus, you should calibrate at regular intervals (we
recommend: every 6 months).
You can determine the actual cell constant of the
conductivity measuring cell by calibrating with the control
standard in the following ranges:
l 0.450 ... 0.500 cm
-1
(e.g. TetraCon, nominal cell constant 0.475)
l
0.800 ... 1.200 cm
-1
(cells with a cell constant of approx. 1)
For the two fixed cell constants, 0.1 cm
-1
and 0.01 cm
-1
,
calibration is not required.
Cell constants outside the ranges mentioned above cannot
be calibrated.
10.2.1 Determining the cell constant (calibration)
Note
This method of automatically determining the cell constant
by calibration with the 0.01 mol/l KCL standard solution can
only be used for measuring cells with cell constants in the
range 0.450 ... 0.500 cm
-1
or 0.800 ... 1.200 cm
-1
.
Note
If the error message E3 appears, refer to chapter 14 W
HAT
TO DO IF
...