Endress+Hauser CPM280 Manuel page 24

Commissioning
Two-point calibration
1. Press <CAL> until Ct1 appears with the AutoCal TEC function indicator.
2. Immerse the pH electrode into the first buffer solution.
3. Press <RUN/ENTER>.
The AutoRead measurement begins. The electrode voltage (mV) or the buffer nominal val-
ue appears on the display. If the measured value is stable, Ct2 appears.
!
At this point, the calibration can be terminated with <M>. This would correspond to a sin-
gle-point calibration. The instrument then uses the Nernst slope -59.16 mV/pH at 25 °C
(77 °F) and determines the asymmetry of the electrode.
4. Immerse the pH electrode into the second buffer solution.
5. Press <RUN/ENTER>.
The AutoRead measurement begins. The electrode voltage (mV) or the buffer nominal val-
ue appears on the display. If the measured value is stable, the instrument displays the value
of the slope and the evaluation of the calibration in calibration range I.
6. Press <RUN/ENTER> again.
COM280 displays the asymmetry in calibration range I.
The asymmetry and slope are evaluated separately. The worst evaluation is indicated on
the display by the sensor symbol.
24
Note!
CPM280
Endress+Hauser