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1)
Polarize the meter for 15 minutes, and then perform the saturated oxygen calibration according
to the 9.2.
2)
Place the electrode into zero-oxygen water, press
to enter calibration mode. When the
stabilized reading is 0.02 ppm to 0.15 ppm after 5 minutes, press again to finish the
calibration, then flashing
0.0%
will show up, the calibration will be finished in several seconds and
0.00 ppm
will show up. Rinse off the electrode with distilled water afterwards.
3)
If the reading is less than 0.02 ppm after 5 minutes, it means the electrode is in good condition
and there is no need to perform zero oxygen calibration. Just press
to return to measurement mode.
4)
If the reading is greater than 0.15 ppm after 5 minutes, it’s time to replace the membrane cap
according to section 9.5.4 or remove the membrane cap and use the polishing paper (DO504) to
lightly polish the gold cathode according to section 9.5.3. Then perform the saturated air
calibration and zero oxygen calibration before measurement.
9.7
Salinity Calibration
Dissolved oxygen is also affected by salinity in water. The meter has automatic salinity
compensation, and the salinity electrode is pre-calibrated before leaving the factory. In general,
there is no need to perform salinity calibration.
Salinity calibration is only needed when replacing a
new electrode. For the procedure of salinity calibration, please refer to 9.9.3 in P2.
For the salinity electrode installed in DO electrode (see picture 4-1), its surface is plated with a layer
of platinum black to reduce electrode polarization. When cleaning salinity electrode,
never brush it
otherwise the coating will be peeled off. Just rinse it off by swirling in pure water to remove
contaminants. For organic contaminants, rinse off with warm water containing detergent or alcohol.
9.8
Barometric pressure manual compensation
Dissolved oxygen is also affected by barometric pressure. The meter has the function of manual
barometric pressure compensation. We suggest resetting the value according to the standard
barometric pressure table when there is a big change in barometric pressure to ensure the accuracy
of barometric pressure compensation (Please see Appendix 2 and Appendix 3). For the procedure
of barometric pressure calibration, refer to 9.9.4.
