wtw inoLab 740, Operating Manual

Page: 86 / 274

pH
86
ConCal
single-point
calibration
Only one buffer solution is required for single-point
calibration. The pH value should lie as close as possible to
the expected measured value. Only the electrode
asymmetry is then newly determined. The slope of the last
two-point calibration is retained.
ConCal
two-point calibration
Use the following buffer solutions:
l pH 7.0 ± 0.5
l Any other buffer solution so that the measuring range is
covered as well as possible
Note
The ConCal calibration procedure has no temperature
compensation. The buffer solutions must have the correct
temperature.
If you use a temperature probe, it is not necessary to enter
the temperature manually.
1 Select the ConCal calibration procedure
(section 6.2.1).
2 Perform the preparatory activities (see section 6.2.2).
3 Start the calibration procedure with
c
.
4 Immerse the electrode and the temperature probe in
the pH 7.0 ± 0.5 buffer solution.
5 If necessary, set the temperature of the first buffer
solution with
82
.
6 Use [Adj. Asy.] to call up the input field for the nominal
pH value of the buffer solution.
7 Use
82
(and
46
) to select the nominal pH value
of the buffer solution (at the current temperature).
8 Confirm the nominal pH value with
g
.
9 Use [ESC] to leave the input field for the nominal pH
value.