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6.2 pH Calibration
1.
Plug the pH sensor into the
pH
socket and the Conductivity/TDS or Temperature sensor into
the
COND/SAL
socket. Switch the meter on.
2.
Ensure that temperature has already been calibrated (see section 7.1) or manually set (see
section 7.4. NOTE: The decimal point in the Temperature reading is shown by a “
∗∗
”, when
the temperature readout is not calibrated.
3.
Remove the wetting cap from the pH sensor. Rinse the pH and Conductivity/TDS or
Temperature sensors in distilled water and blot them dry.
4.
Ensure that the primary and secondary buffers to be used have been correctly selected for
automatic buffer recognition. See section 6.1.
5.
Place both electrodes into a small sample of primary buffer (pH6.88 or 7.00), so that the bulb
and reference junction are both covered as per the diagram below.
DO NOT
place the electrodes directly into the buffer bottle.
6.
Select pH calibration (
→
→
F1:Calibrate
→
→
F3:pH
).
The display should now look something like this…
6*85pH Buffer=6.87 25.0
o
c
Press ENTER to Calibrate,or Edit Buffer.
The current pH reading is shown on the left. Note the “
∗∗
”, indicating that pH is currently not
calibrated. Wait for this reading to stabilise before attempting to calibrate the
90-FL
.
The buffer that the
90-FL
has attempted to recognise is also displayed with the correct value at
the current temperature.
Press
to calibrate to the displayed buffer.
Otherwise, enter an alternative buffer using the Numeric Keypad, and then press
.
The meter is now 1 point calibrated. Note that the “
∗∗
” will not be removed until a full 2 point
calibration has been performed.