horiba LAQUA-PC1100, Инструкция по эксплуатации

Страница: 40 / 117

pH measurement
24
• Inspecting repeatability
You can inspect repeatability using the pH 7 standard solution by returning to the
calibration screen after calibration ends and pressing the
key. Measure the pH 7
standard solution by using the calibrated electrode to display the difference between the
measured value and standard solution value with absolute value.
In order to inspect repeatability, you need to perform calibration of the pH 7 standard
solution with either "USA" or "NIST" set as the standard solution.
1. Clean the calibrated 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. 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 when "ACT" icon is displayed on
the upper part of the screen.
5. Make sure that the pH icon lights while the pH electrode is immersed in the
standard solution.
Stability judgment starts and the pH icon blinks. When the value is stabilized, the pH
icon changes from the blinking state to the lit state and the display is fixed to the
measured value at the stable time.
6. Press the key to start inspection.
"REP" (repeatability) is shown and display changes to the measurement mode.
Stabilized key
key