Hach-Lange HQD - Luminescent Dissolved Oxygen Probe LDO - Manual (Page 10)

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7. If prompted, enter a name for the new method settings. Additional changes made to
the settings of an existing method are automatically saved with the same method
name.
8. Push EXIT until the meter returns to the measurement mode.
Change calibration options
1. Make sure a probe is connected to the meter.
2. Push the METER OPTIONS key and select (Probe Model) Settings.
3. Select Modify Current Settings.
4. Select Calibration Options.
5. Update the settings:
Salinity
correction
Off (default)
Manual
Auto (connect conductivity
probe)
Salinity lowers the solubility of dissolved oxygen in water.
To correct for salinity in the sample, set salinity correction
to manual and then enter the salinity value.
Note: When the HQ40d meter is used, a conductivity probe can also
be connected for automatic salinity measurement and correction. The
parameter setting for the conductivity probe must show salinity.
Salinity value ‰ (default: 35.0 ‰)
When salinity correction is set to manual, enter the salinity
value of the sample. Salinity can be measured with a
conductivity probe.
Pressure units
hPa
mBar
inHg
mmHg
The meter shows the atmospheric pressure at the current
elevation, which is necessary for accurate measurements.
This pressure reading will not agree with readings from
sources such as weather stations, which report atmospheric
pressure at sea level.
Averaging
interval
Off
30 seconds
60 seconds
90 seconds
3 minutes
5 minutes
The averaging interval is useful for samples that contain a
lot of air bubbles, for example in an aeration basin. The air
bubbles cause the dissolved oxygen readings to vary greatly
from one reading to the next. To make the readings more
consistent, increase the averaging interval. The meter will
take measurements at the same frequency but show only
the average over a longer interval.
Note: Labels and options may vary depending on the units selected.
Table 2 Measurement options settings (continued)
Setting Options Description