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properly.
3.Check whether the electrode is damaged.
Press key when measuring value
is not stable during calibration.
Press key
when icon appears.
During calibration, the measuring value
is not stable for ≥3min.
1.Check whether there are bubbles in glass bulb.
2.Replace with a new pH electrode.
pH electrode zero electric potential
out of range
（
<-60mV or >60mV
）
1.Check whether there are bubbles in glass bulb.
2.Check whether pH buffer solution is correct.
3.Replace with new pH electrode.
pH electrode slope out of range
（
<85% or >110%
）
Enter in pre-set due calibration to
remind calibration
Press key to perform calibration or cancel due
calibration setup from parameter P1.2.
5) pH temperature principle
Please note that the closer the temperature of the sample solution is to that of the calibration solution,
the more accurate the readings will be.
6) Factory default setting
For factory default setting, please refer to parameter P1.6 (Item 8.3). Per parameter P1.6, all calibration
data is deleted and the meter restores to the theory value (zero electric potential of pH is 7.00, the slope
is 100%). Some functions restore to the original value (refer to Appendix-I). When calibration or
measurement fails, please restore the meter to factory default setting and then perform re-calibration or
measurement. Please note once set the factory default, all the data deleted will not be retrievable.
5
mV measurement
5.1 ORP measurement
Press key, and switch the meter to mV measurement mode. Connect ORP electrode (need purchase
it separately) and dip it in sample solution, stir the solution briefly and allow it to stay in the solution until
icon appears and get the reading which is ORP value.
ORP means Oxidation Reduction Potential. The unit is mV.
5.2 Notes of ORP measurement
1) ORP measurement does not require calibration. When the user is not sure about ORP electrode quality
or measuring value, use ORP standard solution to test mV value and see whether ORP electrode or
meter works properly.
2) Clean and activate ORP electrode
After the electrode has been used over a long period of time, the platinum surface will get polluted which
causes inaccurate measurement and slow response. Please refer to the following methods to clean and
activate ORP electrode:
