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3.7 pH Calibration
3.7.1 Calibration with pH Buffers - Manual Temperature Compensation
To exit the calibration sequence at any time press the ESC key. This will cancel the pH calibration
and return the instrument to the MODE menu.
Note: Buffer solutions should be carefully prepared as per the manufacturers instructions.
When using manual temperature compensation (no ATC probe fitted) the solution
temperature should be measured and the value entered in the set up menu prior to
calibrating the instrument (refer 3.6.5). The buffer solutions should all be at the same
temperature.
1. Select the pH measuring mode using the Up/Down arrows which toggle between pH and mV
modes. Press the CAL key.
The primary display will show the current pH reading.
The secondary display will show the manually set temperature reading in °C or °F. When manual
temperature compensation is being used the annunciator will indicate MAN.
2. Immerse the electrode(s) in the first buffer solution and allow the instrument to stabilise. When
no pH change of less than 0.005pH is detected over a five second period the endpoint symbol will
be displayed. The symbol display will show:
where 1/3 is the number of calibration points selected in the Calibration Setup menu.
Value should show the manually temperature corrected value of the buffer used.
Press the CAL or STO key.
The display will then show the next part of the calibration sequence if a 2 and/or 3 point calibration
has been selected. If a 1 point calibration only is required the instrument will display CAL OK and
the Eo value and then return to the main measuring screen. The current calibration information,
including the Eo value can be found on the Status screens.
Rinse the electrode(s) in deionised water.
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