pH measurement
30
• pH standard solution setting is CUST
This section describes the procedure for two-point calibration.
CUST can only be selected for LAQUAact-PH120 and LAQUAact-PH130.
1. Clean the pH electrode with pure water (or
deionized water) and wipe it with filter paper
or tissue paper.
2. Open the internal solution filler port of the pH
electrode.
If calibration is performed with the port closed,
the internal solution does not flow and the
measurement value is not stable. Make sure to
keep the port open during calibration.
3. Perform the 1st point calibration. Immerse at
least 3 cm from the tip of the pH electrode in
the pH 7 standard solution.
In order for the internal solution to flow into the
standard solution, make sure to immerse the
liquid junction in the standard solution surely.
4. Press the
key to enter the calibration
mode.
Stability judgment automatically starts and the pH icon blinks until the measured
value stabilizes. When the measured value stabilizes, the pH icon changes from the
blinking state to the lit state.
5. Enter the standard solution value and press the
key or
key.
Calibration to the set standard solution value is performed. The 1st point calibration
ends and "1" calibration history icon lights, indicating that 1st point calibration is
complete.
The display returns to the measurement screen.
Stabilized
key
key
