Xylem ProLab 2000 - Manual (Page 68)

Operation ProLab 2000
68 ba75577e05 11/2013
4.7.5 Determining the cell constant
(calibration in control standard)
Why determine the cell
constant?
Due to aging, the cell constant slightly changes. As a result, an inexact
measured value is displayed. Calibration determines the current value
of the cell constant and stores this value in the instrument.
Therefore, calibrate at regular intervals. The calibration data is stored
in the meter. The calibration data of non-ID sensors is stored in the
meter. For ID sensors, the calibration data is stored in the sensor.
You can determine the cell constant of the conductivity measuring cell
in the ranges 0.450 ... 0.500 cm
-1
, 0.585 ... 0.715 cm
-1
or 0.800 ...
1.200 cm
-1
by calibrating in the 0.01 mol/l KCl control standard or set it
manually in the range 0.250 ... 2.500 cm
-1
or 0.090 ... 0.110 cm
-1
.
Besides, the fixed cell constant 0.010 cm
-1
can be selected.
In the delivery condition, the calibrated cell constant of the meters is set
to 0.475 cm
-1
(conductivity measuring cells LF413T(-ID) and
LFOx1400(-ID).
CalClock The expiry of the CalClock reminds you to clean the measuring cell. It
is still possible to measure.
The CalClock is set to 180 days in the factory. You can change the
interval (see page 66).
Stability control During calibration, the stability control is automatically activated.
Display of calibration
data and download to
interface
You can have the data of the last calibration displayed (see page 87).
Subsequently, you can transmit the displayed calibration data to the
interface, e. g. to a PC, with the <PRINT> key.
Note
The calibration record is automatically transmitted to the interface after
calibrating.