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Macro 900 Operation Manual
V3
© 2013 Palintest Ltd.
www.palintest.com
Page 39 of 147
record book for the Probe. When the offset voltage details have been noted
down, press
OK
then
ESC
repeatedly to return to normal reading mode
.
Remove the Probe from the calibration bottle, rinse thoroughly in de-ionised
water, shake off any excess and dry the outer sleeve with a soft cloth.
13.5.2.
Calibrating the Second Point
The pH electrode can now be calibrated at either pH 4.01 or pH 10.00.
If you
intend to calibrate at both pH 4.01 and pH 10.00, both points must be
calibrated in the same session, i.e. without turning the power off.
If the power is removed after calibrating just one additional point (pH 4.00 for
example), the probe will automatically calculate and save a calibration value for
the uncalibrated third point in order to maintain the electrode's linearity.
To calibrate the second point, fill a calibration bottle with fresh pH 4.01 or pH
10.00 solution and drop the Probe in all the way. Follow the procedure detailed
above, but at step 6, select either pH4.01 or pH10.0, dependent upon the
solution you are using. Wait while the Meter stabilises and calibrates. When the
‘Calibrating 100%’ screen is displayed, t
he calibration report will display the
slope for the pH electrode in millivolts (mV) per pH unit. If this slope goes
below 45mV/pH at 25°C, the pH electrode should be serviced. Press
OK
then
press the
ESC
key repeatedly to get back to the main display.
Remove the Probe from the calibration bottle, rinse thoroughly in fresh water,
shake off any excess and dry the outer sleeve with a soft cloth.
13.5.3.
Calibrating the Third Point
Without switching the Macro 900 Meter off or disconnecting the Probe, fill a
calibration bottle with fresh pH 4.01 or pH 10.00 solution and drop the Probe in
all the way. Follow the procedure detailed above, but at step 6, select either
pH4.01 or pH10.0 dependent upon the solution you are using. Wait while the
Meter stabilises and calibrates. When the ‘Calibrating 100%’ screen is
displayed, the calibration report will display the slope for the pH electrode in
millivolts (mV) per pH unit. If this slope goes below 45mV/pH at 25°C, the pH
electrode should be serviced. Press
OK
then press the
ESC
key repeatedly to
get back to the main display.
Remove the Probe from the calibration bottle, rinse thoroughly in fresh water,
shake off any excess and dry the outer sleeve with a soft cloth. Dampen the
sponge in the storage cap with storage solution and fit it to the pH/ORP
electrode. pH calibration is now complete.
13.6.
Errors During Calibration
If a problem occurs during calibration, an error message will be displayed.
Refer to
Error! Reference source not found.
in section 10 for error message
handling.
13.7.
pH Electrode Efficiency
If the pH electrode becomes worn or clogged, its efficiency and response time