NAVI D-25, Instruction Manual

Page: 82 / 227

3 Functions
3.2 pH calibration history display
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The sensitivity is shown as follows in a 3-point
calibration. Note that the symbol meanings are different
than those notifying the completion of calibration.
Sensitivity for
：
Ion slope of +1 and +2: sensitivity for high concentration side
Ion slope of -1 and -2: sensitivity for low concentration side
Sensitivity for
：
Ion slope of +1 and +2: sensitivity for low concentration side
Ion slope of -1 and -2: sensitivity for high concentration side
Press the
▲
key once more to return to the latest
calibration date display. You can also return to the latest
calibration date display by pressing the
▼
key in the
reverse order.
Criteria for ION offset potential and sensitivity
Ion offset potential is the referential potential used to
determine whether the calibration was conducted
successfully or the usable life of the electrode has been
exceeded.
The following table shows the normal range of the ION
offset potential and sensitivity. If any such values are out
of the range shown below, you need to clean the
electrode and perform calibration again. If you obtain a
value out of the range even after re-calibration, the
electrode needs to be replaced.
Electrode
Ion offset potential
Sensitivity
1 mol/L 1 g/L
Cl
- 27 ± 50 mV 116 ± 50 mV -57.5 ± 5 mV
F
-
-180 ± 50 mV -103 ± 50 mV -60 ± 5 mV
NO
3
- -55 ± 70 mV 43 ± 70 mV -54.5 ± 6 mV
K
+
115 ± 60 mV 23 ± 60 mV 57.5 ± 5 mV
Ca
2+ 29 ± 40 mV -17 ± 40 mV 28.5 ± 3 mV