Xylem WQL-Cond CONDUCTIVITY DATALOGGERS - Manual (Page 31)

WQL-Cond Calibration in control standard (determining the cell constant)
127 ba75822e01 03/2011
6 Calibration in control standard (determining
the cell constant)
Why determine the
cell constant?
Aging slightly changes the cell constant, e. g. due to 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
value of the cell constant and stores this value in the logger.
Thus, we recommend calibrating at regular intervals:
z
on initial commissioning
z before starting a logging job.
Procedure You can determine the actual cell constant of the WQL-Cond logger by
calibrating with the control standard in the following range:
0.450 ... 0.500 cm
-1
(nominal cell constant 0.475 cm -1 )
The cell constant is determined in the control standard,
0.01 mol/l KCl.
In the default condition, the calibrated cell constant of the WQL-Cond logger
is set to 0.475 cm
-1
.
AutoRead During calibration, the AutoRead function is automatically activated. The
AutoRead function checks the stability of the measurement signal and the
stability of the temperature signal. The stability has a considerable effect on
the reproducibility of the measured value.
The current AutoRead measurement can be terminated at any time
(accepting the current value).