Hanna Instruments HI 84429 - Manual (Page 21)

21
Notes:
• A buffer confirmed during the calibration process is removed from the list of calibration buffers
available for further calibration points.
• If the value measured by the instrument is not close to the selected buffer a “Wrong Buffer”
error message will be shown on the display.
Check if the correct buffer has been used or regenerate the pH electrodes by following the
Cleaning Procedure (see page 41). If necessary change the buffer or the electrode or pop the
reference junction.
• If the measured offset isn’t within the preset limits (±45mV) the meter will display the
message “Buffer Contaminated” alternatively with ”Electrode Dirty/Broken”.
• When the reading is stable and close to the selected buffer, the (unstable measurement)
symbol will disappear and the CFM key will become active.
• Press CFM to confirm the calibration.
• The calibrated value will be shown on the display and the third expected buffer value will be
automatically selected.
• After the second calibration point has been confirmed, press STIR to stop stirring.
• Remove the electrode holder with electrodes from the top of the beaker.
• Place the third buffer solution in a beaker and place in beaker holder. Rinse the probes in a
beaker with third buffer rinsing solution.
• Place the electrode holder (with electrodes) in the beaker with third buffer and secure top by
locking. Press STIR.
• If necessary press the ARROW keys in order to select correct buffer value.
• The
(unstable measurement) symbol will be shown on the display until the reading
becomes stable.
• When the reading is stable and close to the selected buffer, the (unstable measurement)
symbol will disappear and the CFM key will become active.
• Press CFM to confirm the calibration. The instrument stores the calibration value and returns
to pH meter/titrator calibration menu, where the date and time for the last pH will be
updated.