Measurement – Hach-Lange HQD - Luminescent Dissolved Oxygen Probe LDO User Manual
Page 5
DOC272.53.80021
5
Measurement
Note: Procedures also apply for rugged model probes.
Auto salinity correction (optional for HQ40d meter)
Dissolved substances affect the amount of oxygen water can hold. Manually input salinity
settings for the most accurate dissolved oxygen measurements or use the Auto Salinity
Correction feature. The Auto Salinity Correction measures dissolved oxygen through the
connection of one LDO101 probe and one CDC401 conductivity cell (set to Salinity
parameter). The value obtained by the CDC401 conductivity cell automatically adjusts the
salinity value for the LDO101 series probe. Auto Salinity Correction is recommended for
dissolved oxygen measurements in samples where salinity varies. Salinity units are
represented as parts per thousand (ppt) or (
º
/
ºº
).
1.
Connect the LDO101 probe and CDC401 conductivity cell to the HQd meter. Turn the
meter on.
Note: Security options must be turned off to enable auto salinity correction.
Before measurement:
The probe must have the correct service-life time stamp. Set the date and time in the meter before attaching the probe.
The probe is factory calibrated and ready for use. For applications that require greater accuracy and precision, perform a
user calibration (
).
When connecting the probe to the meter, make sure to securely tighten the probe locking nut.
If complete traceability is required, enter a sample ID and operator ID before measurement.
Refer to
for measurement errors.
Optimal response time performance is achieved when sample is stirred or probe is placed in flowing conditions.
To deploy the rugged probe at a distance, toss the probe body with a gentle underhand throw. Do not swing the probe by the
cable as this may cause injury to the user, will cause severe strain on the cable and will shorten the service life of the cell.
Damage under these conditions is not covered by the product warranty.
Data is stored automatically in the data log when Press to Read or Interval is selected while in the measurement mode.
When Continuous is selected, data will only be stored when Store is selected.
Salinity affects the concentration of dissolved oxygen in the sample. To correct for salinity effects, refer to
Advanced
operation on page 8
, or follow the
Auto salinity correction (optional for HQ40d meter)
procedures.
1.
Connect the
probe to the meter.
Calibrate the probe if
accuracy better than
± 0.50 mg/L is
required for the
application (refer to
2.
Place the probe
in the sample and
stir gently or add a
stir bar. Move the
probe up and down
to remove any air
bubbles from the
sensor cap.
3.
Select Read.
The display will
show Stabilizing...
and a progress bar
as the probe
stabilizes in the
sample. The display
will then show the
lock icon and the
result will be
automatically stored
in the data log.
4.
Rinse the probe
with deionized water
and blot dry with a
laboratory wipe.
5.
Repeat steps
for additional
measurements.