wtw pH/Ion 340i Mode D'emploi page 8

pH calibration
pH
C t 1
2 4 8
°C
AutoCal TEC
pH
C t 2
2 4 8
°C
AutoCal TEC
pH
- 5 9 4
mV/pH
pH
2
mV
8
Note
If a printer is connected to the interface, a calibration protocol is automatically
printed after a valid calibration.
AutoCal TEC / AutoCal DIN procedure:
The following example shows the AutoCal TEC calibration. In the
AutoCal DIN calibration, Cd... instead of Ct... appears on the display. Other-
wise, both procedures are identical.
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 Ct1 and the function dis-
play AutoCal TEC appears. The sensor symbol displays the evaluation of
the last calibration (or no sensor symbol in the delivery state or after the
measurement parameter has been reset).
TP
l Immerse the pH electrode into the first buffer solution.
l When measuring without a temperature sensor:
Enter the temperature of the first buffer solution with < > < > while
pressing the <RUN/ENTER> key.
l Press <RUN/ENTER>. The AutoRead measurement begins. The elec-
trode voltage (mV) or the buffer nominal value appears on the display. If
the measured value is stable, Ct2 appears.
Note
At this point, the AutoCal TEC 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
TP
determines 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>. The AutoRead measurement begins. The elec-
trode voltage (mV) or the buffer nominal value appears on the display.
l When the measured value is stable, 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/Ion 340i