wtw inoLab 740, Operating Manual

Page: 89 / 274

pH
89
6.3 Measuring the pH value
Preparatory
activities
Perform the following preparatory activities when you want
to measure:
Note
Incorrect calibration of pH electrodes leads to incorrect
measured values. Calibrate regularly. The measuring
system has to be calibrated before measuring.
Temperature probe You can measure with or without a temperature probe. If a
temperature probe is connected, it is indicated on the
display by
v
.
Note
If you use a pH electrode without temperature probe, you
can also use the temperature probe of a D. O. probe or a
conductivity measuring cell (see section 5.5.2 M
EASURING
THE TEMPERATURE
). If you use the temperature probe of a D.
O. probe or a conductivity measuring cell,
y
or
z
appears
on the display.
1 Connect the electrode to the measuring module.
2 Call up the Display mode with
m
.
3 Call up the pH measured value display with
46
.
4 Adjust the temperature of the solutions and measure
the current temperature if the measurement is made
without a temperature probe.
5 With manual temperature input:
Use
82
to call up the temperature input field and
adjust the temperature.
Use
[ESC] to terminate the temperature input.
6 Calibrate or check the measuring system with the
electrode.
7 Switch to the measuring mode with
m
.
1 Perform the preparatory activities.