9
4.2.5.Calibration description:
(a) This meter can adopt random one-point, two-point or three-point automatic calibration,
after the first point calibration (see item 4.2.2.), press
to exit calibration
mode and enters into measuring mode. The indication icon
“
”
will appear on
the lower left corner of LCD. When the measuring accuracy is
≤±
0.1pH, user just
need to choose one kind buffer solution to take one-point calibration according to the
measuring range.
(b) After the second point calibration, (see item 4.2.3.), press
to exit calibration
mode and enter into measuring mode. The indication icon
“
”
for
tow-point calibration will appear on the lower left corner of LCD. User can choose
pH4.00 and pH 7.00 to calibrate if the measurement is just within the acidity range
and choose pH 7.00 and pH 10.01 to calibrate if just within the alkalinity range.
(c) User should choose three-point calibration so as to reach a more accurate
measurement if the measuring range is wide, or if the electrode has been used for long
or has ageing phenomenon. As to the new electrode which be used for the first time, it
must be calibrated by three-point calibration to keep the unanimity of the meter slope
adjustment with the pH electrode.
4.3. PH Solution Test:
Immerge pH electrode into the sample solution after washing and dry it, rock the
electrode holder and still, when the LCD appears the icon
“
”
to take the reading
after displaying value to be stable.
Note: According to the pH equal temperature measuring theory: the closer the
temperature of the sample solution with the calibration solution, the more accurate
the measuring value will be acquired. So please comply with this theory.
