Hanna Instruments HI 9124 - Manual (Page 12)

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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.