EUTECH INSTRUMENTS CD 650, Instruction Manual

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2.4 pH Calibration with a User-defined Buffer
If you selected ‘USER’ (Custom) buffer in the pH Setup, the following screen is
shown when you enter calibration mode. You need to prepare at least 2 custom
buffers of known pH values.
Figure 18 : User-define Buffer Screen
1. Rinse the electrode in clean water and prepare electrode for calibration.
2. Dip the probe in custom calibration buffer. The tip of the probe must be
completely immersed into the solution. Stir the probe gently to create a
homogeneous solution.
3. The screen shows 2 readings. The upper display shows the pH reading of
the solution with respect to previous calibration (if any) & lower display
shows the pH reading of the solution without any calibration. Use &
keys to adjust the upper display to the pH value of your custom buffer.
4. Press ENTER key to confirm the calibration.
5. Rinse the probe with clean water. Place it in the next buffer and follow steps
2, 3 and 4 to calibrate other points.
Function Keys available in pH Calibration mode:
TEMP (F1)
Goes to temperature calibration
CLR-C (F2)
Clears previous calibration (if any) after ENTER key is pressed for the
confirmation screen
NEXT (F3)
Shows calibration report
Note: Custom buffer solution values should be at least 1 pH unit apart
from each other. Otherwise, the meter will not accept the buffer values.
Note: If you wish to completely re-calibrate the meter, you need to clear
previous calibration data. Press CLR-C (F2) key to clear previous
calibration. The meter shows you confirmation screen. Press ENTER key
to confirm deleting previous calibration.