Hanna Instruments HI 9321 - Manual (Page 12)

1 2
RESET BUTTON
The RESET button (see pages 4-5, #V) should be used when the
instrument displays erroneous messages due to strong electrical inter-
ference or when the instrument's power supply was disconnected
before the meter was switched off.
It is recommended to recalibrate the unit before proceeding.
pH CALIBRATION
Calibrate the instrument often, especially if high accuracy is required.
The instrument should be re-calibrated for pH:
a) Whenever the pH electrode is replaced.
b) At least once a week.
c) After testing aggressive chemicals.
d) If higher accuracy is required.
e) After pressing RESET.
PREPARATION
Pour small quantities of the buffer solutions into clean beakers.
For accurate calibration and to minimize cross contamination use two
beakers for each buffer solution. One for rinsing the electrode and a
second for calibration.
To obtain accurate readings, use pH 7.01 and pH 4.01 if you are
going to measure acidic samples or pH 7.01 and pH 10.01 for
alkaline measurements.
HI 7007
H
I
7 0
0 4
HI 7004
HI 7007
CALIBRATION
HI 7007
RINSE