Xylem MULTI 3400 MULTI-PARAMETER METERS - Manual (Page 38)

Operation Multi 3400i
38
4.4.5 Determining the cell constant (Calibration in the control
standard)
Why determine the cell
constant?
Aging slightly changes the cell constant, 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 deter-
mines the current value of the cell constant and stores this value in the
instrument.
Thus, you should calibrate at regular intervals.
In the delivery condition, the cell constant of the measuring instruments
is set to 0.475 cm
-1
(conductivity measuring cell TetraCon 325).
AutoRead The calibration procedure automatically activates the AutoRead func-
tion. The AR display indicator flashes. The calibration process is fin-
ished when AR stops flashing.
Displaying the calibra-
tion data
You can view the data of the last calibration on the display. The pro-
ceeding is described on page 48.
Printing the
calibration protocol
The calibration record contains the calibration data of the current cali-
bration. You can transmit the calibration protocol to a printer via the se-
rial interface (see page 51).
Note
You can automatically print a calibration record after the calibration. To
do so, connect a printer to the interface according to section 4.7.2 be-
fore calibrating. After a valid calibration, the record is printed.
Sample printout:
CALIBRATION PROTOCOL
14.04.01 11:37
Device No.: 99990000
Calibration Conductivity
Cal time: 14.04.01 / 11:37
Cal interval: 180d
Cal Std.: 0.01 mol/l KCL
40.0 °C
Conduct./Tref25: 1413µS/cm
Cell Const : 0.478 1/cm
Probe : +++