Xylem MULTI 1970I PORTABLE MULTIPARAMETER METERS - Manual (Page 42)

Operation Multi 1970i
40
4.5.5 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 instrument
is set to 0.475 cm
-1
(conductivity measuring cell TetraCon 325).
AutoRead In calibration, the AutoRead function is automatically activated. The AR
display indicator flashes. The calibration process is finished when AR
stops flashing.
Displaying the
calibration data
You can view the data of the last calibration on the display. The pro-
ceeding is described on page 50.
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 4.8.2
before calibrating. After a valid calibration, the record is printed.
Sample printout:
CALIBRATION PROTOCOL
14.04.02 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 : +++