7
109118-1 Rev. A,10/96
2
2.1
Calibrating a pH Electrode
1-point calibration
Place the tip of the electrode in a calibration buffer and press
It does not matter which buffer you do first.
If you have the '
auto read
' feature (see Section 2.3) turned on,
the meter will automatically endpoint when the reading is stable
and the appropriate buffer symbol will appear on the display.
If you don't have '
auto read
' on, press
Rinse the tip of the electrode with distilled or deionized water
and goto Measuring samples (Section 2.2) or 2-Point calibration.
NOTE
If you are using an ATC probe (or an electrode
incorporating ATC), temperature is being measured and
the buffer value is being corrected for temperature (see
Section 2.6). If you are not using an ATC in the system,
the Model 440 assumes a temperature of 25°C .
2-point calibration
Place the tip of the electrode in the second buffer and
press
If you have the '
auto read
' feature (see Section 2.3) turned on,
the meter will automatically endpoint when the reading is stable
and the appropriate buffer symbol will appear on the display.
The meter will also briefly display the electrode slope. If you
don't have '
auto read
' turned on, press
to accomplish the
same thing.
Rinse the tip of the electrode with distilled or deionized water
and goto Measuring samples (Section 2.2).
NOTE
For maximum accuracy, we recommend using an ATC
probe or the 3-in-1 Combination electrode which
includes an ATC probe. If you do not have an ATC probe
you should make sure that all buffers and samples are
at 25°C.
cal
cal
read
read
