Hanna HI 9124, Instruction Manual, Page: 12 / 28

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• If the reading is not close to the selected buffer, “ WRONG ”
and “ WRONG ” will blink alternatively;
• If the reading is close to the selected buffer and the reading is
stable, the “ READY ” symbol is displayed and the “ CFM ” symbol
starts blinking on the LCD, asking for confirmation.
• Press the
CFM
key: the value is stored into memory and the meter
returns to normal mode.
Notes: • The meter automatically skips the buffer used for the first
calibration point to avoid erroneous procedure. A difference
of at least 1.5 pH unit is required between the two buffers
used for the offset and slope calibration: once calibrated at
either pH 7.01 or 6.86, the instrument automatically
ignores the other value for the second point (same for pH
10.01 and 9.18).
• During calibration, the secondary LCD shows the selected
buffer value. For the HI 9125 model, it is possible to
display the buffer temperature during calibration by
pressing
RANGE .
• To clear a previous calibration and return to the default
values, in calibration mode press CFM , then CAL before
the first buffer is accepted. The LCD will show “
CLr CAL
”
for one second, and then will return to normal mode.
ONE-POINT CALIBRATION
For optimum accuracy it is always recommended to perform a
two-point calibration, but for a faster operation a single-point
calibration can be used. pH 7.01 or pH 6.86 (NIST) are normally
used for this purpose, even though the meters can be calibrated with
any of the 5 memorized calibration values.
After calibrating the first point (see above), press the
CAL key to end
the calibration procedure.