LaMotte pH PLUS Direct Meter - Manual (Page 14)

3.2.4 pH Calibration using Pb standard buffers
1.
Pour a known pH buffer standard solution into a clean container, e.g. pH
6.97. Power on meter, and it will automatically enter the measurement
mode. Select the pH mode by pressing the
MODE key if necessary
2. Dip both the pH electrode and temperature probes into the pH 6.97 buffer
solution. Swirl gently and wait for the reading to stabilize (approx. 30
seconds depending on the electrode condition).
3. Press the
CAL key to enter the pH calibration mode. “CA” will be displayed
momentarily and the display will flash the current uncalibrated reading.
4. To abort or cancel the calibration without accepting the new value, press
the
CAL key. The meter then reverts to the pH measurement mode.
5. To proceed with the calibration, allow the reading to stabilize. The meter
will automatically recognize either pH 4.10 or 6.97 buffer. Press the
ENTER key to confirm the calibration and the LCD will display “CO”
momentarily. The meter will revert to the measurement mode.
6. For a 2-point calibration, repeat step 3 with pH 4.10 buffer for better
accuracy.
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