LaMotte pH PLUS Direct Meter - Manual (Page 12)

3.2.2 pH Calibration using USA standard buffers
1. Pour a known pH buffer standard solution into a clean, dry container, e.g.
pH 7.00. Power on the 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 pH 7.00 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 with 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 pH 4.01, 7.00 or 10.01 buffers. 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 or 3-point calibration, repeat step 3 with other pH buffer values of
4.01 and/or 10.01 for higher accuracy.
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