Hanna Instruments HI99151, Instruction Manual, Page: 12 / 20

12
OPERA
TIONAL GUIDE
Two-point calibration
Proceed with steps 1 through 3 under single‑point
calibration using 7.01 pH (pH 6.86 for NIST) buffer first.
Then follow steps below:
The ”
pH 4.01 USE ” message is then displayed.
Place the probe in the second calibration buffer (pH 4.01
or 10.01, or, if using NIST, pH 4.01 or 9.18). When the
second buffer is accepted, the LCD will display “
SAVE ”
for 1 second and the meter will return to the normal
measurement mode.
If the buffer is not recognized or the slope is out of accepted
range ”
--- WRONG ” is displayed. Change the buffer, clean
the electrode or press any key to exit calibration.
For better accuracy it is always recommended to carry out
a two‑point calibration.
After the calibration procedure has been completed, the
tag is turned on together with the calibrated points.
Exiting calibration and resetting default values
After entering the calibration mode and before the first point
is accepted, it is possible to quit the procedure and return
to the last calibration data by pressing the button. The
LCD displays “
ESC “ for 1 second and the meter returns to
normal mode.
To reset the default values and clear a previous calibration,
press the
SET button after entering the calibration mode
and before the first point is accepted.
The LCD displays “
CLEAR “ for 1 second, the meter resets to
the default calibration and the tag with the calibrated
points on the LCD disappears.