10
ATC
PROCEDURE
The user has a choice of 7 memorized buffers: pH 1.68, 4.01, 6.86, 7.01,
9.18, 10.01 and 12.45.
It is always recommended to perform a two-point calibration, however the
instrument also allows a one-point calibration, as described on page 11.
TWO-POINT CALIBRATION
For most applications it is recommended that pH 7.01 or 6.86 buffers be used
as the first calibration point and pH 4.01 (for acidic samples) or pH 9.18/
10.01 (for alkaline samples) as the second calibration point.
Note:
The pH 12.45 buffer is not for general measurement; use only if the
sample is very alkaline to avoid sodium error.
Immerse the pH electrode and the temperature probe approximately
4 cm (1½) into the buffer solution of your choice (pH 1.68, 4.01,
6.86, 7.01, 9.18, 10.01 or 12.45) and stir gently. The temperature
probe should be close to the pH electrode.
Press the
CAL
key.
CAL
and
pH
tags will be on, and the
CLEAR
CAL if new electrode
tag will blink.
Press the
CLR
key if you are using a new electrode or want to clear the
calibration history. The instrument will display the
donE
message for
a few seconds.
It is very important to clear the calibration history when a new electrode is
used because all error and warning messages that appear during calibration
depend on the calibration history.
Press the
CAL
key, or wait a few seconds to continue.
Note:
The above behavior happens only if calibration history is not empty.
The instrument will display the measured pH on the primary LCD, and
the most common buffer (7.01) on the secondary LCD along with
CAL
,
pH
and
BUFFER 1
tags.
The tag will blink until the reading has stabilized.
CLEAR CAL if new electrode
pH
CAL
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