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pH
12. pH
12.1. pH CALIBRATION
For high accuracy, frequent calibrations are recommended.
Additionally, the pH range should be recalibrated:
• whenever the pH electrode is replaced
• at least once a week
• after testing aggressive chemical,
• if “CAL DUE“ tag is blinking (if enabled)
• if “Out of calibration range” message blinks during measurement (if enabled).
HI98169
offers a choice of seven standard buffers (pH 1.68, 3.00, 6.86, 7.01, 9.18, 10.01 and
12.45) and up to five custom buffers.
For accurate pH measurements a five-point calibration is recommended, a minimum of a two-point
calibration is suggested.
The instrument will automatically skip the buffers used during calibration and the buffers which are in
a ±0.2 pH window around one of the calibrated buffers.
Clear Calibration
To clear the previous calibrations, press the
CAL
key, then press
Clear
. All of the old calibration data is
cleared and the calibration continues. If the calibration is cleared before confirming the first calibration
point the instrument returns to the measurement mode.
Custom Buffers
Custom buffers are set to the value at 25 °C. When calibrating with custom buffers the buffer value
can be modified by pressing
Custom
. Use the / keys to change the buffer value (± 1.00 pH)
based on the temperature reading. Press
Accept
to save the value or press the
ESC
key to return to
the calibration screen.
Mili pH Buffers
Mili pH buffers are only available if the pH resolution is set to 0.001 pH when you enter calibration.
The exact value of the mili pH buffer is reported in the label, buffers can be modified in a ± 0.020 pH
window.
