Xylem MULTI 3400i pH/Cond MULTI-PARAMETER METERS - Manual (Page 37)

pH/Cond 3400i Operation
37
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
(TetraCon 325 conductivity measuring cell).
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 calibration
data
You can view the data of the last calibration on the display. The pro-
ceeding is described on page 51.
Printing the
calibration protocol
The calibration protocol contains the calibration data of the current cal-
ibration. You can transmit the calibration protocol to a printer via the se-
rial interface (see page 53).
Note
You can automatically print a calibration protocol after the calibration.
To do so, connect a printer to the interface according to section 4.7.2
before 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 : +++