Hach-Lange HQD User Manual

DOC272.53.80021

User instructions

Luminescent Dissolved Oxygen Probe: Model LDO10101,
LDO10103, LDO10105, LDO10110, LDO10115 or LDO10130

Safety Information

Read all labels and tags attached to the instrument. Personal injury or damage to the
instrument could occur if not observed.

Electrical equipment marked with this symbol may not be disposed of in European public di sposal systems after
12 August of 2005. In conformity with European local and national regulations (EU Directive 2002/96/EC),
European electrical equipment users must now return old or end-of life equipment to the Producer for disposal at no
charge to the user.

Note: For return for recycling, please contact the equipment producer or supplier for instructions on how to return
end-of-life equipment, producer-supplied electrical accessories, and all auxiliary items for proper disposal.

Overview

Figure 1 on page 2 shows the LDO101 series probe, a luminescent dissolved oxygen (LDO®)

probe. The LDO10105, LDO10110, LDO10115 or LDO10130 rugged probe is available with a
5, 10, 15, or 30 meter cable. The LDO10101 or LDO10103 standard probe is available with a
1 or 3 meter cable. The probe provides measurement o f the dissolve d oxygen concentration in
wastewater, drinking water and general applications. For BOD applications, use the
LBOD10101 probe equipped with LDO technology and an incorporated stirrer.

Specifications

Specifications are subject to change without notice.

Specification Details

Dissolved oxygen range 0.1 to 20.0 mg/L (ppm) 1 to 200% saturation
Dissolved oxygen accuracy
% saturation resolution 0.1%

Temperature range 0 to 50 °C (122 °F)
Storage temperature 0 to 40 °C (104 °F)
Response time T90% at 10 sec (when stirred)
Temperature resolution 0.1 °C (32.18 °F)
Temperature accuracy ± 0.3 °C (32.54 °F)
Pressure resolution 1 hPa
Pressure accuracy ± 0.8%
Minimum sample depth 25 mm (0.984 in.)

Dimensions

Cable connection Digital output and connector compatible with HQd meters
Warranty Probe is covered by a 3 year warranty. Sensor cap is covered by a 1 year warranty.

± 0.1 mg/L for 0 to 8 mg/L
± 0.2 mg/L for greater than 8 mg/L

Standard diameter: 15 mm (0.59 in.), Length: 103 mm (4.1 in.), Total length (standard):
200 mm (7.9 in.), Total length (rugged): 220 mm (8.7 in.), Cable length: 1 or 3 meter (3.3
or 9.8 ft.). Rugged diameter: 15 mm (0.6 in.), Length: 16 mm (0.63 in.), Cable length: 5,
10 15 or 30 meter (16.4, 32.8, 49.2, or 98.4 ft.)

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Figure 1 Probe overview

1 LDO sensor cap 5 Pressure sensor module

®

2 Rugged probe (5, 10, 15 or 30 meter cable) 6 iButton

Integrated Products, Inc.)

3 Standard probe (1 or 3 meter cable) 7 Pressure sensor module cap
4 Probe cable

(iButton is a registered trademark of Maxim

Preparation for use

1. Verify that the LDO sensor cap and iButton are installed correctly. Avoid touchi ng the

sensor cap with a hand, fingers or any surface that may scratch the cap.

Note: Make sure the LDO sensor cap and iButton have the same lot code and the iButton label
faces upward.

2. Rinse the sensor cap with deionized water and blot dry.

Note: The LDO sensor cap must be pre-conditioned if dissolved oxygen monitoring periods are
longer than 6 hours. Refer to Maintenance on page 6.

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Calibration

Before calibration:

The probe must have the correct service-life time stamp. Set the date and time in the meter before attaching the probe.
The LDO101 probe is factory calibrated, ships with an iButton-provided calibration and is ready for use. The factory

calibration will not allow a user calibration. To enable calibration, select User Cal as the Current Method in the LDO101
settings menu and follow the 100% (water-saturated air) procedures below.

It is not necessary to recalibrate when moving a calibrated probe from one HQd meter to another if the additional meter is
configured to use the same calibration options. If the additional HQd meter uses different calibration options (e.g. calibration
standards or acceptance criteria), calibrate the probe or change the method settings to select a different method. If using
Factory Cal, a new method will need to be created.

To view the current calibration, select the DATA LOG key, View Probe Data, then View Current Calibration
Tighten the probe locking nut securely when connecting the probe to the meter.
For probes that are continuously immersed in aqueous solutions, condition the sensor cap for 72 hours. Refer to

Maintenance on page 6.

If any two probes are connected, Push the UP or DOWN arrow to change to the single display mode in order to show the
Calibrate option.

A new method can be created if custom calibration or measurement settings are desired.
Refer to Troubleshooting on page 11 for calibration errors.
% saturation or mg/L calibration methods are available in the Modify Current Settings menu.

Water-saturated air (100%) calibration

Calibration notes

• Probes are initially calibrated at the factory. However , regular calibration by the user is

recommended for the best measurement accuracy.

• To calibrate rugged probes, use a wide neck bottle or flask (such as a 250 mL
Erlenmeyer flask).

• If the sensor cap is wet, carefully dry the cap with a nonabrasive cloth and put the
probe back in the bottle.

• An additional zero point calibration can be added to the calibration routine. Refer to

Change calibration options on page 10.

• The slope value is the comparison between the latest calibration and the factory
calibration expressed as a percentage. If the calibration slope does not meet the
acceptance criteria, the display will show Slope out of range. Refer to

Troubleshooting on page 11.

• Data is stored automatically in the data log when Press to Read or Interval is
selected while in Measurement Mode. When Continuous is selected, data is stored
only when the Store key is pushed.

• The calibration is recorded in the probe and the data log. The calibration is also sent
to a PC, printer or flash memory stick, if connected.

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Note: Procedures also apply for rugged model probes.

1. Connect the
probe to the meter.
The LDO101 probe
contains a factory
calibration. Remove
the shroud from the
probe.

6. Remove the
stopper. Carefully
dry the cap with a
non-abrasive cloth
and place the probe
in the bottle.

2. Push the

CALIBRATE key to

create a new method
to enable user
calibration.

7. Select Read.
The display will
show Stabilizing...
and a progress bar
as the probe
stabilizes. The
display will highlight
the standard value.

3. Push the

METHODS key, and

select User Cal ­100%. Push

OK.

8. Select Done to

view the calibration
summary.

4. Add
approximately ¼
inch (6.4 mm) of
reagent water to a
narrow-neck bottle,
such as a BOD
bottle.

9. Select Store to
accept the
calibration and
return to the
measurement mode.
Install the shroud on
the probe body.

5. Insert a stopper
and shake
vigorously for
approximately 30
seconds to saturate
the entrapped air
with water. Allow up
to 30 minutes for
contents to
equilibrate to room
temperature.

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Measurement

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 (Calibration on page 3).
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 Troubleshooting on page 11 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.

Note: Procedures also apply for rugged model probes.

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

Calibration on
page 3.).

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

4. Rinse the probe
with deionized water
and blot dry with a
laboratory wipe.

result will be
automatically stored
in the data log.

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 CDC4 01 conductivity cell automa tically adju st s 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 (

1. Connect the LDO101 probe and CDC401 conductivity cell to the HQd meter. Turn the
meter on.

º

/ºº).

5. Repeat steps 2.
to 4. for additional
measurements.

Note: Security options must be turned off to enable auto salinity correction.

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