SCHOTT handylab multi 12, Руководство по эксплуатации

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Operation handylab multi 12
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4.2.4 pH calibration
Why calibrate? pH electrodes age. This changes the asymmetry (zero point) and slope
of the pH electrode. As a result, an inexact measured value is dis-
played. Calibration determines the current values of the asymmetry
and slope of the electrode and stores them in the measuring instru-
ment. Thus, you should calibrate at regular intervals.
When to calibrate?
l
After connecting another electrode
l
When the sensor symbol flashes:
– after the calibration interval has expired
– after a voltage interruption, e. g. after changing the batteries
AutoCal TEC is specially matched to the SCHOTT technical buffer solutions as a fully
automatic two-point calibration. The buffer solutions are automatical-
ly recognized by the measuring instrument. Depending on the instru-
ment setting (see section 4.8 C
ONFIGURATION
), the instrument displays
the relevant buffer nominal value or the current electrode voltage in
mV. The calibration can be terminated after the first buffer solution.
This corresponds to a single-point calibration. To do this, the instru-
ment uses the Nernst slope (-59.2 mV/pH at 25 °C) and determines the
asymmetry of the electrode.
AutoRead The calibration procedure automatically activates the AutoRead func-
tion.
The current AutoRead measurement can be terminated at any time
(accepting the current value) by pressing <RUN/ENTER>.
Displaying the calibra-
tion 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 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 O
UTPUTTING THE CALIBRATION PROTOCOL ON THE
INTERFACE
, page 53).
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.