wtw pH/Ion 340i Mode D'emploi page 9

pH/Ion 340i
pH
A S Y
2 4 8
°C
ConCal
pH
7 1 0 3
2 4 8
°C
ConCal
pH
S L O
2 5
°C
ConCal
pH
4 7 5 5
2 8
4
°C
ConCal
pH
- 5 9 2
mV/pH
pH
3
mV
ConCal procedure:
l Connect the pH electrode to the measuring instrument.
If necessary, press the <M> key repeatedly until the status display pH (pH
measurement) or U (measurement of the ORP voltage) appears.
l Press the <CAL> key repeatedly until the display ASY and the function
display ConCal appears. The sensor symbol displays the evaluation of the
last calibration (or no sensor symbol in the delivery state or after the mea-
surement parameter has been reset).
TP
l Immerse the pH electrode in the first buffer solution
(pH 7.0 ± 0.5 in two-point calibration).
l When measuring without a temperature sensor:
Enter the temperature of the first buffer solution with < > < > while
pressing the <RUN/ENTER> key.
l Press the <RUN/ENTER> key.
The measured pH value appears on the display.
l Set the measured value to the nominal pH value of the buffer solution (at
the current temperature) with < > < >.
TP
l When the measured value is stable, press the <RUN/ENTER> key. The
value of the asymmetry appears.
l Press the <RUN/ENTER> key. SLO appears.
Note
At this point, the ConCal calibration can be terminated with <M>.
This corresponds to a single-point calibration. To do this, the
instrument uses the Nernst slope (-59.2 mV/pH at 25 °C) and de-
TP
termines the asymmetry of the electrode.
l Immerse the two-point calibration pH electrode in the second buffer so-
lution to continue.
l When measuring without a temperature sensor:
Enter the temperature of the second buffer solution with < > < > while
pressing the <RUN/ENTER> key.
l Press <RUN/ENTER>.
l Set the measured value to the nominal pH value of the buffer solution (at
the current temperature) with < > < >.
TP
l When the measured value is stable, press the <RUN/ENTER> key. The
instrument displays the value of the slope and the calibration evaluation.
l Press <RUN/ENTER>. The instrument displays the value of the asymme-
try.
l Switch to the measuring mode with <M>.
pH calibration
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