Hach LDO User manual
DOC273.98.90592
LDO sensor
05/2017, Edition 1
Addendum—Operation with the SC1500 Controller
Addendum—Betrieb mit dem SC1500 Controller
Adenda—Funcionamiento con el controlador SC1500
Addendum—Fonctionnement avec le contrôleur SC1500
Addendum—Funzionamento con il controller SC1500
Addendum—Bediening met de SC1500 Controller
Addendum—Operation med SC1500 Controller
Addenda—Działanie z kontrolerem SC1500
English..............................................................................................................................3
Deutsch.......................................................................................................................... 11
Español.......................................................................................................................... 20
Français......................................................................................................................... 29
Italiano............................................................................................................................ 38
Nederlands....................................................................................................................46
Dansk..............................................................................................................................55
Polski.............................................................................................................................. 63
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Operation
Configure the sensor
Use the Settings menu to enter identification information for the sensor and to change options for
data handling and storage.
For information about sensor installation, refer to the user manual.
Make sure that all of the Settings menu values are correct for the application.
1. Go to MENU>SENSOR SETUP>[Select Sensor]>SETTINGS.
2. Select an option, ENTER. The list of available options is shown in the table below.
Option Description
Name Changes the name that corresponds to the sensor on the top of the measure screen.
The name is limited to 10 characters in any combination of letters, numbers, spaces or
punctuation.
Unit Temperature–Sets the temperature units to °C (default) or °F.
Measurement–Set the measurement units in mg/L, ppm or % .
Altitude/Pressure–Set the altitude in m or ft, or set the atmospheric pressure units in
mmHg or torr. (Default value = 0 ft)
Altitude/Pressure Enter the value of the altitude or atmospheric pressure. This value must be accurate to
complete % saturation measurements and calibration in air. (Default = 0 ft).
Salinity Enter the salinity value. Salinity range: 0.00 to 250.00 parts per thousand (‰). (Default
value = 0)
Signale average Set the time interval to average signal in seconds
Cleaning interval Set the time interval for manual sensor cleaning in days (Default value = 0 days. A value
of 0 days disables the clean interval.)
Reset cleaning interval Set the time interval to the last saved clean interval
Data logger interval Sets the time interval for data storage in the data log—0.5, 1, 2, 5, 10, 15 (default), 30,
60 minutes.
Reset Restores the configurable default values for the sensor. Does not change the setting for
slope or offset.
Enter the atmospheric pressure value
The factory setting for atmospheric (air) pressure is 0 ft, or sea level. To change the default value,
use the steps in this procedure. The adjustment for air pressure is entered as either elevation or as
pressure units (preferred).
Note: Accurate air pressure is critical for saturated air calibration. Use only absolute pressure, not adjusted. If the
absolute air pressure is not known, use the correct elevation for the location.
1. Go to MENU>SENSOR SETUP>[Select Sensor]>SETTINGS>UNIT>AIR
PRESSURE/ALTITUDE.
2. Select one of the unit options listed:
Option Description
Altitude ft Feet—unit of measure for elevation
Altitude m Meters—metric unit of measure for elevation
Air pressure mmHg Millimeters of mercury—metric unit of measure for absolute air pressure
Air pressure torr Unit of measure for absolute air pressure
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3. Confirm the selection. The value entry screen will show the selected units.
4. Enter the value, then confirm.
Enter a salinity correction value
Dissolved oxygen measurements in saline samples can show an apparent DO value that is very
different from the actual DO value. To correct for the influence of dissolved salts in a sample, enter a
salinity correction factor.
Note: If the presence or amount of salinity in the process is unknown, consult with the treatment facility engineering
staff.
1. Use a conductivity meter to measure the conductivity of the sample in mS/cm at a reference
temperature of 20 °C (68 °F).
2. Use Table 1 to estimate the salinity correction factor in parts per thousand (‰) saturation.
Note: The chloride ion concentration, in g/kg is equal to the chlorinity of the sample. Salinity is calculated with
the formula: Salinity = 1.80655 × chlorinity.
Salinity can be calculated with the relationship in section 2520 B of Standard Methods for the
Examination of Water and Wastewater.1,
3. Go to MENU>SENSOR SETUP>[Select Sensor]>SETTINGS>SALINITY.
4. Enter the salinity correction factor and confirm.
Table 1 Salinity saturation (‰) per conductivity value (mS/cm)
mS/cm ‰ mS/cm ‰ mS/cm ‰ mS/cm ‰
5 3 16 10 27 18 38 27
6 4 17 11 28 19 39 28
7 4 18 12 29 20 40 29
8 5 19 13 30 21 42 30
9 6 20 13 31 22 44 32
10 6 21 14 32 22 46 33
11 7 22 15 33 23 48 35
12 8 23 15 34 24 50 37
13 8 24 17 35 25 52 38
14 9 25 17 36 25 54 40
15 10 26 18 37 26
Calibration for measurements
The sensor is calibrated to specification at the factory. The manufacturer does not recommend
calibration unless periodically required by regulatory agencies. If calibration is required, let the sensor
come to equilibrium with the process before calibration. Do not calibrate the sensor at setup.
Table 2 shows options for calibration.
1Standard Methods for the Examiniation of Water and Wastewater, 20th Edition. Editors Lenore
S. Clesceri, Arnold E. Greenberg and Andrew D. Eaton, p. 2-48-2-29 (1998). The relationship
between Chlorinity and Oxygen Solubitity is provided in the same reference in 4500-O:I p. 4-131.
4 English
Table 2 Calibration options
Option Description
Air calibration Recommended calibration method. This calibration modifies the slope.
Calibration Calibration by comparison with a hand-held DO meter . This calibration modifies the offset.
Reset calibration Resets the calibration gain (slope) and offset to the factory default: default gain=1.0; default
offset=0.0
Air calibration
User notes:
• Make sure that calibration bag has water inside.
• Make sure that the seal between the calibration bag and the sensor body is tight.
• Make sure that the sensor is dry when it is calibrated.
• Make sure the air pressure/elevation setting is accurate for the calibration location.
• Allow enough time for the sensor temperature to stabilize to the temperature of the calibration bag
location. A large difference in temperature between the process and the calibration location can
take up to 15 minutes to stabilize.
1. Remove the sensor from the process. Use a wet cloth to clean the sensor.
2. Put the entire sensor in a calibration bag with 25-50 mL of water. Make sure that the sensor cap
is not in contact with the water inside the calibration bag and that no water drops are on the
sensor cap.
3. Use a rubber band, tie or hand to create a tight seal around the sensor body.
4. Let the instrument stabilize for 15 minutes before calibration. Keep the calibration bag out of
direct sunlight during stablization.
5. Make sure that the current absolute air pressure or elevation is configured correctly.
Note: The manufacturer recommends the use of absolute or actual air pressure as a best practice.
6. Go to MENU>SENSOR SETUP>[Select Sensor]>CALIBRATION>AIR CALIBRATION.
7. Select the option for the output signal during calibration:
Option Description
Active The instrument sends the current measured output value during the calibration procedure.
Hold The sensor output value is held at the current measured value during the calibration procedure.
Transfer A preset value is sent during calibration. Refer to the controller user manual to change the preset
value.
8. The controller will show "Put the entire sensor in the bag with water.". Allow the value to stabilize.
Push ENTER to accept the stable value. Alternately, let the calibration continue until the display
shows "Task was succesfully completed. ".
9. When the sensor is calibrated, put the sensor into the process. Push ENTER.
English 5
Figure 1 Air calibration procedure
If the value does not stabilize, the display will show "Unable to Calibrate" followed by an error
message. Table 3 shows the error message and resolution for calibration problems.
Table 3 Air calibration error messages
Message Description Resolution
Calibration failed! Gain correction is
too high.
The calculated gain value is too high. Repeat the calibration.
Calibration failed! Gain correction is
too low.
The calculated gain value is too low. Repeat the calibration.
Calibration failed! Unstable The value did not stabilize in the maximum
allowed calibration time.
Repeat the calibration.
Calibration by comparison
This calibration method uses an alternate sensor attached to a hand-held meter.
1. Put the alternate sensor into the process. Put the second sensor as close as possible to the first
sensor.
2. Wait for the DO value to stabilize.
3. On the controller for the first sensor, go to MENU>SENSOR SETUP>[Select
Sensor]>CALIBRATION>CALIBRATION.
4. Select the option for the output signal during calibration:
Option Description
Active The instrument sends the current measured output value during the calibration procedure.
Hold The sensor output value is held at the current measured value during the calibration procedure.
Transfer A preset value is sent during calibration. Refer to the controller user manual to change the preset
value.
5. The controller will show:
• "Is the reading stable?"
• The current dissolved oxygen measurement
• The current temperature measurement
6. When the measurement is stable, push ENTER. The display will show an entry screen.
Note: The measurement will usually stabilize in 2 to 3 minutes.
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If the value does not stabilize, the display will show "Unable to Calibrate" followed by an error
message. Table 4 shows the error message and resolution for calibration problems.
Table 4 Sample cal error messages
Message Description Resolution
Calibration failed! Offset is too high. The calculated offset value is too high. Repeat the calibration.
Calibration failed! Offset is too low. The calculated offset value is too low. Repeat the calibration.
Calibration failed! Unstable The value did not stabilize in the maximum allowed
calibration time.
Repeat the calibration.
Exit the calibration procedure
1. During calibration, push the BACK key. Three options are shown:
Option Description
Cancel Stop the calibration. A new calibration must start from the beginning.
Return to
calibration
Return to the current calibration.
Exit Exit the calibration temporarily. Access to other menus is allowed while the calibration
continues in the background. A calibration for a second sensor (if present) can be
started. To return to the calibration, push the MENU key and select Sensor Setup,
[Select Sensor].
2. Select one of the options. Confirm.
Reset calibration defaults
Calibration settings can be reset to the factory defaults. Gain and offset values are set to 1.0 and 0.0,
respectively.
1. Go to MENU>SENSOR SETUP>[Select Sensor]>CALIBRATION>RESET CALIBRATION.
2. The display will show a confirmation message. Confirm to reset the sensor to the factory default
calibration curve.
Maintenance
D A N G E R
Multiple hazards. Only qualified personnel must conduct the tasks described in this section of the
document.
D A N G E R
Explosion hazard. Do not connect or disconnect electrical components or circuits to the equipment
unless power has been switched off or the area is known to be non-hazardous.
D A N G E R
Explosion hazard. Substitution of components may impair suitability for Class 1, Division 2. Do not
replace any component unless power has been switched off and the area is known to be non-
hazardous.
N O T I C E
The hazardous location certified version of this product does not fulfill the requirements of the 94/9/EC Directive
(ATEX Directive).
English 7
Maintenance schedule
The maintenance schedule shows minimum intervals for regular maintenance tasks. Perform
maintenance tasks more frequently for applications that cause electrode fouling.
Note: Do not disassemble the probe for maintenance or cleaning.
Maintenance task Recommended minimum frequency
Clean the sensor 90 days
Inspect the sensor for damage 90 days
Calibrate the sensor As recommended by regulatory agencies
Clean the sensor
Clean the exterior of the sensor with a soft, wet cloth.
Note: If the sensor cap must be removed for cleaning, do not expose the interior of the cap to direct sunlight for
extended periods of time.
Set or change the clean interval
Application conditions may need shorter or longer durations between manual sensor cleanings. The
default clean interval is 0 days. To change the interval, refer to the steps in this procedure.
1. Go to MENU>SENSOR SETUP>[Select Sensor]>SETTINGS>CLEANING INTERVAL.
2. Change the shown value as needed. Confirm the change.
• To turn off the clean interval, set the value to '0'.
Change the sensor cap
WARNING
Potential explosion hazard. The sensor setup cap is not rated for hazardous location use.
Replacement sensor caps and setup caps are shipped with installation instructions. Refer to the
included instructions to change the cap. After the new sensor cap is installed, make sure that the lot
number on the sensor cap is the same lot number that is read by Modbus. The sensor uses the
calibration information from the sensor cap.
For best performance and accuracy, replace the sensor cap:
• Every two years, or more frequently if necessary
• When routine inspection shows significant erosion of the sensor cap
Troubleshooting
Diagnostic and test menu
The diagnostic and test menu shows current and historical information about the LDO sensor.
To access the diagnostic and test menu, go to MENU>SENSOR SETUP>[Select
Sensor]>MAINTENANCE.
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Refer to Table 5.
Table 5 Maintenance menu
Option Description
Sensor information Software version—Shows the installed software version
Boot pogram— Shows the installed boot version
Driver version—Shows the installed software driver version
Sensor cap lot code Shows the sensor cap manufacturing lot
Serial number Sensor serial number
Gain correction Adjust the calibration gain value.
Range: 0.50 to 2.00
Offset correction Adjust the calibration offset value (mg/L or ppm).
Range: –3.00 to +3.00
Phase diagnostics Shows the phase for total, red and blue wavelengths. Updates once per second.
Amplitude diagnostics Shows the amplitude for red and blue wavelengths. Updates once per second.
Days remaining to clean Shows the number of days until the next scheduled manual cleaning.
Sensor life Shows the number of days until the next scheduled sensor cap replacement.
Error list
If an error occurs, the reading on the measurement screen flashes. Output behavior is determined by
controller settings. Refer to the controller manual for details.
To show the current sensor errors, go to MENU>SENSOR DIAGNOSTICS>[Select Sensor]>ERROR
LIST. Refer to Table 6.
Table 6 Error list for the LDO sensor
Error Possible cause Resolution
Red amplitude is too low. (Value is below
0.01)
or
Blue amplitude is too low. (Value is below
0.01)
The sensor cap is not
installed, or is not installed
correctly.
Remove the sensor cap and
install it again.
The light path is blocked in
the sensor cap.
Inspect the inside of the sensor
cap and lens.
The sensor is not operating
correctly.
Make sure that the LED is
flashing. Contact the
manufacturer.
Warning list
When the warning icon flashes (sc100 and sc200) or when the screen turns yellow (sc1000), a
message is shown on the bottom of the measurement screen. On the sc1000, the screen turns
yellow to show a warning. To show the current sensor warnings, go to MENU>SENSOR
DIAGNOSTICS>[Select Sensor]>WARNING LIST. Refer to Table 7.
Table 7 Sensor warning list
Warning Definition Resolution
EEPROM setup error Storage is corrupt. The values have
been set to the factory default.
Contact technical support.
EEPROM error
English 9
Table 7 Sensor warning list (continued)
Warning Definition Resolution
Temperature < 0 °C The process temperature is below 0 °C
(32 °F)
Increase the process temperature or
stop use until the process temperature
is in the sensor specification range.
Temperature > 50 °C The process temperature is above 50 °C
(120 °F)
Decrease the process temperature or
stop use until the process temperature
is in the sensor specification range.
Red amplitude is too low. Value falls below 0.03 Refer to Error list on page 9 .
Red amplitude is too high. Value is greater than 0.35 Call technical support.
Blue amplitude is too low. Value is below 0.03 Refer to Error list on page 9.
Blue amplitude is too high. Value is greater than 0.35 Call technical support.
Sensor cap lot code
missing.
The sensor cap code has become
corrupt. The code has been reset
automatically to the default cap and lot
codes.
Complete the sensor setup cap
procedure. If no setup cap is available
for the sensor cap, call technical
support.
Event list
The Event list keeps a log of changes to how data is recorded by the sensor. To show sensor events,
go to MENU>SENSOR DIAGNOSTICS>[Select Sensor]>EVENT LIST.
Refer to Table 8.
Table 8 Event list for the sensor
Event Description
Altitude/Pressure unit change Atmospheric pressure or altitude units have changed.
Altitude/Pressure change The value for altitude or atmospheric pressure has changed.
Temperature change The units for temperature have changed.
Unit change A new unit of measurement has changed.
Salinity change The value for salinity has changed.
Reset Sensor settings have been reset to the default values.
Sensor setup change The sensor setup has changed.
Cleaning interval change The time between sensor cleaning has changed.
Sensor life change The time between sensor cap replacements has changed.
10 English
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