Hanna Instruments HI 98170 - Manual (Page 19)

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It is recommended to calibrate the instrument frequently, especially if high
accuracy is required.
The ppm range should be recalibrated:
• Whenever the ISE electrode is replaced.
• When the ion charge is changed in SETUP menu.
• At least once a week.
• After testing agressive chemicals.
• When calibration alarm time out is expired - “CAL DUE” tags blink (if
feature is enabled).
Due to electrode conditioning time, the electrode must be kept immersed a few
seconds to stabilize. The user will be guided step by step during calibration
with easy to follow tags on the LCD. This will make the calibration a simple and
error-free procedure.
PROCEDURE
Select the proper ion charge in SETUP menu (see SETUP for details, page 25).
Note: If “undF” option is selected in SETUP menu, calibration must be performed
in at least two points, otherwise “----” message will be displayed on the LCD
if exiting calibration after confirming the first used standard.
Pour small quantities of the buffer solutions into clean beakers. If possible, use
plastic beakers to minimize any EMC interferences.
For accurate calibration and to minimize cross-contamination, use two beakers for
each buffer solution. One for rinsing the electrode and one for calibration.
The instrument offers a choice of six memorized standard solutions: 0.1, 1, 10,
100, 1000, 10000 ppm and calibration up to five points.
Remove the protective cap from the ISE electrode.
FIVE-POINT CALIBRATION
• Immerse the ISE electrode approximately 4 cm
(1½”) into the less concentrated standard solution
and stir gently.
• Press CAL. The primary LCD will display the ppm
value using the current offset and slope. The “CAL”
and “Cal Point 1” tags will appear and “0.100” ppm
standard will be displayed on the secondary LCD.
• If necessary, press the ARROW keys to select a different standard value.
• The “ ” tag will blink on the LCD until the reading is stable.
• When the reading is stable and close to the selected standard, the “CFM” tag
blinks.
• Press CFM to confirm calibration.
ISE CALIBRATION (HI 98172 only)
LOG CFM