Hanna Instruments HI 121 - Manual (Page 23)

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For greatest accuracy, it is recommended to calibrate the instrument frequently.
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 display. This will make the
calibration a simple and error-free procedure.
PREPARATION
In SETUP menu, select the proper ion charge.
Note: If “undF” option is selected in SETUP menu, calibration must be
performed in two points, otherwise “----” message will be displayed on
the LCD if exiting calibration after confirming the first used standard.
Pour small quantities of the standard 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.
PROCEDURE
One or two-point calibration is available, using five memorized standard
solutions: 0.1, 1, 10, 100, 1000 ppm.
Press CHANNEL or simply ISE from the left keyboard to select ISE channel.
Remove the protective cap from the ISE electrode.
TWO-POINT CALIBRATION
• Immerse the ISE electrode approximately 4 cm
(1½”) into the first standard 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 the 0.1 ppm buffer
will be displayed on the secondary LCD.
• If necessary, press the ARROW keys to select a different standard solution.
• The “ ” tag will blink on 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.
CAL
ISE CALIBRATION
CFM