43
42
ONE POINT CALIBRATION (OFFSET)
• Immerse the ISE electrode into the se-
lected buffer (e.g. 10 ppm) solution and
shake briefly.
Note: the electrode should
be submerged ap-
proximately 4 cm
(1½") into the solu-
tion.
• Press CAL. The primary LCD will display
the ION value using the current offset and
slope, with the "CAL" and "
BUF
1
" indicators.
• Select the buffer value
by pressing UP or
DOWN until the sec-
ondary LCD displays
the value of the first
solution (e.g. “
10
”).
• Only when the read-
ing is stable, will the
"
BUF
1
" indicator stop
flashing (after about
30 seconds) and the
"CFM" the indicator
start blinking.
• Press CFM to confirm the cali-
bration. The meter stores the
reading (and adjusts the offset
point). The calibration solution
value is then displayed
on the primary LCD
and the secondary
LCD will display the ex-
pected 2
nd
calibration
value.
4 cm
(1
½
")
CAL
1
ppm
ppm
CAL
BUF
CFM/
2
ppm
ppm
CAL
BUF
°C
°C
CFM
For greatest accuracy, it is recommended
that the instrument is calibrated frequently.
The standard calibration program of the meter,
however, is prepared for 2 (maximum) buff-
ers. The selectable ION values are:
ppm 0.1, 1, 10, 100, 1000.
Due to electrode conditioning time the elec-
trode must be kept immersed a few seconds
to stabilize. The meters are equipped with a
stability indicator and the user will be guided
step by step with easy indications on the
display during the ION calibration. This will
make the calibration a simple and error-free
procedure.
INITIAL PREPARATION
Pour small quantities of the
chosen ION calibration solu-
tion into individual beakers. If
possible, use plastic beakers
to minimize any EMC inter-
ferences.
For accurate
calibration use
two beakers
for each solu-
tion, the first
one for rinsing
the electrode, the second one for calibration.
By doing this, contamination between the buff-
ers is minimized.
PROCEDURE
• Press ION to select the ION
measurement mode.
• Remove the protective cap
from the ISE electrode.
ION CALIBRATION (for pH 301 only)
ION