Hanna Instruments HI 9023 - Manual (Page 10)

19
• Rinse the electrode with clean or distilled water first and then
with pH 4.01 (or 10.01) buffer. Dip the electrode into the pH
4.01 (or 10.01) solution and stir gently.
• Wait for the "pH" symbol to stop flashing. Press CFM to
confirm the calibration.
PROCEDURE FOR HI 9024C AND HI 9025C:
In order to calibrate HI 9024C and HI 9025C, there is a choice of
5 memorized buffers: 4.01, 6.86, 7.01, 9.18 and 10.01 pH.
• Make sure that the meter is in the pH mode.
• Remove the protective cap and rinse the electrode with some of
the buffer calibration solution that you are going to use first.
ONE-POINT CALIBRATION:
It is always recommended to perform a two-point calibration for
optimum accuracy. In case of necessity, it is possible to carry out only
a one-point calibration with the instruments. The offset buffers, that is
the Standard 7.01 or the NIST 6.86 are the
most appropriate for this purpose even though
both meters can be calibrated with any of
the 5 memorized calibration solutions.
• Immerse the pH electrode into a pH
buffer solution (e.g. pH 6.86) and stir
gently.
Note: The electrode should be submerged approximately 4 cm
(1½") into the solution. With the temperature probe located
as close to it as possible.
CFM
CAL
1
BUF pH °C
HI 7006
CAL
4 cm (1½
")
CAL
1
BUF pH
20
• Once the electrode is submerged in the
buffer solution, the LCD will notify the
user if the reading is not stable by an
intermittent "NOT READY". Only when the
reading is stable, will it change to a
blinking "READY" and "CON".
• Press the CFM key to confirm the calibra-
tion. If the reading is not close to the
selected buffer, "WRONG
1
BUF
" and "WRONG
" will blink alternatively. If the reading is
close to the selected buffer, the meter
stores the reading (and adjusts the offset
point). The buffer value is then displayed
on the primary LCD and the secondary
LCD will display another buffer value
(e.g."4.01").
• Press the CAL key and the calibration pro-
cess is ended with only the offset of the
meter calibrated. For best accuracy how-
ever, do not press CAL and proceed with a
two-point calibration.
TWO-POINT CALIBRATION
After calibrating at 6.86 or 7.01 pH (see above), for the second
buffer use pH 4.01 if you are going to measure acidic samples,
and pH 9.18 or pH 10.01 if you are measuring alkaline solutions.
• Proceed as described in “One-point cali-
bration above but do not end the
calibration by pressing CAL.
• After the first calibration point is con-
firmed, immerse the pH electrode into
the second buffer solution (pH 4.01,
9.18 or 10.01) and stir gently.
Note: The electrode should be submerged
approximately 4 cm (1½") into the
solution with the temperature probe
located as close to it as possible.
• Select the second buffer value on the
secondary display by pressing the Ï °C
or Ð C C C C C key.
NOT READY
READY
CON
CFM
WRONG WRONG 1
BUF
CAL
1
BUF
pH
pH
CAL
HI 7004
4 cm (1½
")
°C
°C
or