13
Two-point calibration
Any two of the 5 memorized buffers can be used for this purpose.
However, it is recommended that pH 6.86 or 7.01 is chosen as the
first point and pH 4.01 (acidic) or pH 9.18/10.01 (alkaline) as the
second point.
• Proceed as described in “One-point calibration” above but do not
quit calibration by pressing CAL at the end.
••
••
• After the first calibration point is con-
firmed, immerse the pH electrode and the
temperature probe approximately 4 cm
(1½") in the second buffer solution and
stir gently. The temperature probe should
be close to the pH electrode.
• If necessary, press "VC" or "WC" to
select a different buffer value.
Note: The meter will automatically skip the buffer used for the first
point. It also skips 6.86 if 7.01 was used, and viceversa.
Likewise, it will skip 9.18 if 10.01 was used, and viceversa.
• The "NOT READY" indication will blink on LCD until
the reading has stabilized.
• When the reading is stable, "READY" and "CFM" will blink. Press
CFM to confirm the calibration.
• If the reading is close to the selected buffer, the meter stores the
reading and returns to normal operational mode.
• If the value measured by the meter is not
close to the selected buffer, "WRONG " and
"WRONG " will blink alternately. In this case
check if the correct buffer has been used, or regenarate the
electrode by following the cleaning procedure below. If necessary
change the buffer or the electrode.
Note: Press RANGE to display the temperature reading
on the LCD during calibration (pH211, pH212,
pH213 only).
4 cm
(1½")
20
For refillable electrodes:
If the filling solution (electrolyte) is more than 2½ cm (1") below the
fill hole, add HI 7082 or HI 8082 3.5M KCl Electrolyte Solution for
double junction or HI 7071 or HI 8071 3.5M KCl+AgCl Electrolyte
Solution for single junction electrodes.
For a faster response, unscrew the fill hole screw during measure-
ments.
For AmpHel
®
electrodes:
If the electrode does not respond to pH changes, the battery is run
down and the electrode should be replaced.
MEASUREMENT
Rinse the electrode tip with distilled water. Immerse the tip (bottom 4
cm /1½") in the sample and stir gently for a few seconds.
For a faster response and to avoid cross contamination of the samples,
rinse the electrode tip with a few drops of the solution to be tested,
before taking measurements.
STORAGE
To minimize clogging and assure a quick response time, the glass bulb
and the junction should be kept moist and not allowed to dry out.
Replace the solution in the protective cap with a few drops of HI 70300
or HI 80300 Storage Solution or, in its absence, Filling Solution
(HI 7071 or HI 8071 for single junction or HI 7082 or HI 8082 for
double junction electrodes). Follow the Preparation Procedure above
before taking measurements.
Note: NEVER STORE THE ELECTRODE IN DISTILLED OR DEIONIZED WATER.
PERIODIC MAINTENANCE
Inspect the electrode and the cable. The cable used for connection to
the meter must be intact and there must be no points of broken
insulation on the cable or cracks on the electrode stem or bulb.
Connectors must be perfectly clean and dry. If any scratches or cracks
are present, replace the electrode. Rinse off any salt deposits with
water.
For refillable electrodes:
Refill the reference chamber with fresh electrolyte (HI 7071 or HI 8071
for single junction or HI 7082 or HI 8082 for double junction elec-
trodes). Allow the electrode to stand upright for 1 hour.
Follow the Storage Procedure above.
AmpHel
®
is a registered Trademark of "Hanna Instruments"
To Next Page
Loading...
Need help?
General
