horiba D-72, Instruction Manual

Page: 35 / 88

pH measurement
D-72 19
5. Check that the pH value is stable while the pH electrode is immersed in the
standard solution, then press the key.
Stabilization judgment starts and the HOLD icon blinks. When the value is stabilized,
the HOLD icon changes from the blinking state to the lit state and calibration to the
standard solution value at the measured temperature is performed. The 1st point
calibration ends and the calibration history icon "7" lights, indicating that pH 7
calibration is complete.
6. Perform the 2nd point calibration. As with the
step 2.,wash the pH electrode and immerse it
in the pH 4 standard solution. As with the step
4., immerse at least 3 cm from the tip of the pH
electrode.
7. Press the key.
The current measured value display appears.
8. Check that the pH value is stable while the pH electrode is immersed in the
standard solution, then press the key.
Stabilization judgment starts and the HOLD icon blinks. When the value is stabilized,
the HOLD icon changes from the blinking state to the lit state and calibration to the
standard solution value at the measured temperature is performed. The 2nd point
calibration ends and the calibration history icon "4" lights, indicating that pH 4
calibration is complete.
Two-point calibration is complete.
When calibrating three points or more, use the same procedure to continue calibrating
the 3rd and subsequent points after the 2nd point calibration. You can calibrate up to five
points. Also, you can inspect repeatability using the pH 7 standard solution. About the
repeatability inspection procedure, refer to “ Inspecting repeatability ” (page 21).
Stabilized
key
Stabilized
key