Lovibond SensoDirect Oxi200 User manual

SensoDirect Oxi200
Dissolved Oxygen Meter
Operating instructions
GB

2
Declaration of CE-Conformity
The manufacturer: Tintometer GmbH
Schleefstraße 8 a
44287 Dortmund
Deutschland
declares that this product
Product name: SensoDirect Oxi200
with all optional items conforms to the following regulations:
EMC EN 55 022 : 6 / 1993 class B
EN50082-1(EN61000-4-6,
EN 61000-4-4, EN 61000-4-3,
EN 61000-4-2)
The product conforms to the regulations of the EMC Directive
89/336/EEC and 73/23/EEC.
Dortmund, March 12, 2003
Cay-Peter Voss,
Managing Direc-

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Table of Contents Page
1. Scope of delivery ..............................................................4
2. System description ............................................................4
3. Connections ......................................................................6
4. Display ..............................................................................6
5. Keypad..............................................................................8
6. Startup ..............................................................................8
7. Measurement...................................................................10
8. Conguration of the unit...................................................10
8.1 Resolution of display for oxygen measurement ................11
8.2 Zero point temperature oset...........................................11
8.3 Salinity: salinity correction ................................................12
8.4 Display of sensor status ..................................................12
8.5 Pressure Absolute, display of absolute pressure .............13
8.6 Selection of temperature unit °C /°F.................................13
8.7 Selection of unit for oxygen partial pressure .....................13
8.8 “Power o”: automatic unit switch-o ..............................13
9. Oxygen measurement .....................................................14
9.1 Absolute pressure............................................................14
9.2 Salinity correction.............................................................15
10. Calibration of oxygen measurement ................................15
10.1 Performing calibration ......................................................15
11. Oxygen sensor.................................................................16
11.1 Technical data..................................................................16
11.2 Operating notes...............................................................17
11.3 Design of the sensor........................................................18
11.4 Care and maintenance.....................................................19
12. Result memory ................................................................21
12.1 Storing results..................................................................21
12.2 Displaying stored results ..................................................21
12.3 Deleting stored results .....................................................21
13. Error messages and troubleshooting................................22
14. Technical data..................................................................23
15. Accessories .....................................................................26

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1. Scope of Delivery
Standard:
• Lovibond®SensoDirect Oxi200
• Measuring cell
• Batteries, 4*AA 1,5 V Cells
• Operating instructions
Set:
• Lovibond®SensoDirect Oxi200
• Batteries, 4*AA 1,5 V Cells
• Measuring probe
• Carrying case
• Operating instructions
2. System description
The Lovibond®SensoDirect Oxi200 is a sturdy, water-
tight handheld meter designed for daily measurements
in the area of eld or laboratory analysis.
It is used to measure oxygen concentration in surface
waters and groundwater as well as for waste water
and service water analysis.
The system complies with the requirements in EN
60529 relating to protection class IP67 and water-
proof/dustproof properties.
The permanent protective plating on the unit serves
not just as impact protection but also as a storage
compartment for the sensor and as an anti-slip device
when the meter is used in an upright position.

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Microprocessor technology and 4*AA 1,5 V batteries
allow unit operation without battery change for 12,000
hours or more.
A „Low Bat” indicator in the display shows the user
when it is time to change the batteries.
The required temperature compensation for the system
is performed automatically following connection of the
temperature sensor (NTC, 10 kOhm) that is integrated
as standard in the Tintometer oxygen sensor.
The AUTO HOLD feature enables the user to identify
stable results and call them up on the display.
The standard MEAS measuring function is for conti-
nuous measurement of oxygen concentrations, partial
pressures or saturations.
The absolute atmospheric pressure is measured in the
unit and is automatically used, for among other things,
calculation of the oxygen partial pressure or calibration
of the system.
The integrated automatic salinity correction feature is
based on the „International Oceanographic Tables“ and
is user-selectable in the range from 0% to 70% via the
conguration function of the unit.
The system is calibrated using the oxygen in the air.
A sensor evaluation is automatically shown in the
display (or can be called up via the menu) after each
calibration.
An internal memory for 20 results is integrated in the
unit as standard. The memory stores location, result
and temperature.
The memory is called up via the display.

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3. Connections
Oxygen sensor

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4. Display
Main Display: Result or user
prompt
[mmHg] Oxygen partial pressure
in mmHg
[hPa] Oxygen partial pressure
in hPa
[mg/l] Oxygen concentration
[%O2] Oxygen saturation
Secondary
display: Result - temperature
or user prompt
[%] Percent (sensor evaluation)
[°C/°F] Temperature unit
[Δ
!
]Warning index - battery
[SAL] Salinity correction on/o
[OK] Measuring signal stable
[CAL] Auto. oxygen calibration
[hPa] Absolute air pressure

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5. Keypad
[Meas] Continuous measurement -
standard
[Hold] Auto-Hold: Automatic
retaining of stable result
[On/O] On / O
[▲] [▼]Display change: partial pressure,
concentration or saturation. Leaf
through menu or display
[Rcl] Display of stored results
[Cal] Calibration mode
[Store] Storage of current result or acceptance of
unit conguration
[Menu] Unit conguration
6. Startup
The unit is supplied with integrated batteries as stan-
dard and is therefore ready for immediate use. You have
to unscrew the unit to insert or change the batteries.
When inserting the batteries, ensure correct polarity!

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Screw the unit back together carefully without exerting
too much pressure on the gasket seal.
If the [Δ
!
] symbol appears together with „bAt” in the
lower section of the display, this means that the bat-
teries are nearly empty and need replacing.
However, the unit will continue to function for a certain
period of time.
If „bAt“ appears in the upper section of the display, this
means that the batteries are completely empty.
Only use the matching Tintometer oxygen sensors!
Other sensors may cause serious damage to the meter
and the sensor.
The sensor or temperature sensor must be plugged in
before the unit is switched on.
Switch the unit on via the [On/O] key.
The system must be calibrated when the system is
rst used.
Following measurement, please switch the unit o
using the [On/O] key.
See the enclosed Operating Instructions for more
detailed information on storage and care of the sen-
sors.

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7. Measurement
Measuring mode MEAS
After the unit is switched on, it is automatically in the
standard measuring mode (MEAS).
You can switch to the standard MEAS measuring mode
by pressing the [Meas] key.
The display shows the current, possibly still uctuating
result and [Meas].
If the result is stable, the [ok] arrow appears in the
display.
Measuring mode HOLD
Pressing the [Hold] key takes you into the AUTO HOLD
measuring mode.
In this mode, the recorded result is checked by the
system in line with the predened stability criteria until
these criteria are met.
The display shows Auto/HOLD in alternating mode
together with the result.
Once a stable reproducible value is present, the result
is shown permanently in the display („frozen”).
The display also shows HOLD and the temperature.
If you press the [Hold] key again, the measuring cycle
starts again and runs until the stability criteria are
met.
8. Conguration of the unit
To congure the unit, press the [Menu] key.
The rst menu item appears.

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If you press the [Menu] key again, the display jumps
to the next menu item.
You can set the various parameters using the [▲] [▼].
keys.
Press the [Store] key to store and conclude congu-
ration.
The unit then switches back to measuring mode.
You can terminate the conguration process by pres-
sing the [Meas] or [Hold] key.
Settings made up to this point are not stored.
The unit retains the previous settings.
8.1 Resolution: resolution of display
for oxygen measurement
Hi: high resolution, restricted measuring
ranges
Lo: low resolution, maximum measuring
ranges
Auto: automatic, maximum measuring ranges
8.2 [Offset] = Zero point temperature offset
-10.0°C...10.0°C or -18.0°F...18.0°F:
The zero point for temperature measurement is offset
by this value.
This enables the user to balance out any occurring
sensor deviations:
Displayed temperature = measured temperature
offset
Off: zero point offset is inactive (=0.0°)
+

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8.3 Salinity: salinity correction
0...70,0 ‰: Selection of salinity correction
off: Salinity correction inactive
8.4 Display of sensor status
Indication of the sensor status that is computed
internally during every calibration depending on the
sensor used.
100% The electrode is in excellent condition.
30...90% The condition of the electrode is ade-
quate.
<30% The electrode is old from use or soiled.
If there is no improvement after you have cleaned and
recalibrated the sensor (see operating instructions for
electrode), you need to replace the sensor.

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8.5 Pressure Absolute, display of ab-
solute pressure
Display of the absolute atmospheric pressure in hPa.
8.6 Selection of
temperature unit °C /°F
°C All temperature values in degrees Celsius
°F All temperature values in degrees Fahrenheit
(°C = 0.556*°F-17.8 or °F = 1.8*°C+32)
8.7 Selection of unit for oxygen partial
pressure
hPa: Oxygen partial pressure in hPascal
mmHg: Oxygen partial pressure in mm
mercury column
8.8 “Power off”: automatic unit
switch-off
If no key is pressed during the switch-o delay period,
the unit switches o automatically after the selected
time has run down.
The desired delay time is entered in minutes.
If P.oFF = oFF, automatic unit switch-o is inactive.
9. Oxygen measurement

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Please note the following when measuring dissolved
oxygen:
The sensor should be calibrated after the unit is swit-
ched on.
The sensor and the liquid to be measured must have
the same temperature (leave until the temperatures
match if necessary)
Measurements are only suciently accurate if perfor-
med with a minimum ow rate of approx. 30 cm/sec;
in other words, the liquid must be constantly stirred or
a suitable stirring mechanisms must be used.
Remove the protective cap prior to measurement.
The oxygen partial pressure, the oxygen concentration
[mg/l] and the oxygen saturation [%] are calculated on
the basis of the sensor signal and the temperature.
The measurement is based on steam-saturated air in
accordance with DIN38408-C22.
9.1 Absolute pressure
The absolute atmospheric pressure is measured in
the unit.
The measured air pressure primarily aects saturation
measurement [%] but also plays a major role during
automatic oxygen calibration.
During depth measurements, there are dierent pres-
sure conditions at the sensor and it is necessary to
correct the oxygen saturation [%].
The results for oxygen concentration [mg/l] and oxygen
partial pressure are not aected by this.
9.2 Salinity correction

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The higher the salinity, the lower the solubility of oxy-
gen in water; in other words, fewer mg of oxygen are
dissolved per litre of water at the same oxygen partial
pressure.
It is therefore necessary to rst enter the salinity of
the medium in order to determine the oxygen con-
centration.
The salinity correction feature is adjusted for aqueous
media whose chemical composition corresponds to
that of seawater.
Correction is based on the „International Oceanogra-
phic Tables” (IOT).
10. Calibration of oxygen measurement
The sensor data of oxygen sensors are aected by
ageing and manufacturing tolerances that result in
uctuations. You should therefore calibrate the unit
with the sensor on a regular basis.
The sensor is automatically adjusted to the oxygen
content of the air (20.95%; 1-point calibration).
We recommend calibration prior to each series of
measurement.
10.1 Performing calibration
Remove the protective cap from the sensor prior to
calibration.
Pat the diaphragm dry using a soft cloth.
Starting calibration: -Press [Cal] key.

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‘CAL’ appears in the display.
As soon as the results for oxygen, temperature and
air pressure are constant, calibration is terminated
automatically.
The sensor status (‘ELEC’, valuation in 10% steps) is
then briey displayed.
Depending on the temperature, a correctly calibrated
sensor shows a result of 102..114% (oxygen satu-
ration).
If error messages occur during calibration, please see
the troubleshooting tips.
If calibration is not completed after you have waited a
lengthy period of time, at least one of the three measu-
ring signals (oxygen partial pressure, temperature or
air pressure) is not stable.
In this event, you should check the measuring setup.
11. Oxygen sensor
11.1 Technical data:
Measuring range of the unit:
Oxygen partial pressure: 0 ... 1200 hPa O2
Temperature: -5.0 ... 50.0 °C
Sensor: Galvanic, active dia-
phragm-covered sen-
sor,withintegratedNTC
resistor
Response time: 95% in 10 sec., tem-

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perature-dependent
Operating pressure: max. 3 bar.
Installation diameter: Ø 12.0 ±0.2 mm (ts a
1/2„screwconnection,
for example)
Overall length: approx. 220 mm (incl.
anti-kink protection)
Installation length: approx. 110 mm
Weight: approx. 180 g
Operating temperature: 0 to +40°C
Storage temperature: 0 to +60°C
The galvanic self-polarising sensor with silver cathode
and lead anode with potassium hydroxide as an elec-
trolyte, is an active system.
The lead anode, the silver cathode and the electrolyte
are used up during operation.
The sensor is aected by ageing over time.
Continuous maintenance of the sensor is therefore
necessary.
11.2 Operating notes
a.) The oxygen sensor must always be kept moist to
prevent the membrane from drying out. To this end,
you should place the sensor in deionised water in the
supplied storage cap.
If the diaphragm has dried out, the sensor needs to be
watered for approx. 2 hours prior to measurement. It

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then needs to be recalibrated.
b.) The sensors may only be used with the correspon-
ding units. The use of the sensors in combination with
unsuitable units can destroy the unit and the sensors!
c.) Unit and sensor must be handled with care and
used in accordance with the technical data outlined
above. Always protect the connector and connection
socket against soiling and dirt.
d.) Do not insert the connector at an angle. If the
connector is inserted properly, you should be able to
press it in without using force.
When disconnecting the sensor, do not pull it by the
cable but always by the connector sleeve.
e.) Remove the sensor storage cap before performing
measurements.
11.3 Design of the sensor
The housing of the sensor probe is made of PVC. With
the exception of the sensor shaft, all parts must be
serviced regularly and replaced if necessary.
Storage cap: The storage cap is used to moisten the
membrane. This increases the service life of the sensor.
The storage cap contains deionised water.
Membrane cap: the diaphragm head is covered with
a Teon membrane.
The diaphragm cap is lled with KOH electrolyte and
screwed onto the sensor shaft in such a way that there
are no air bubbles.
Damaged membrane or air bubbles in the membrane
Sensor
shaft
O-Ring-
seal
membrane
cap
Rell
opening

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cap cause incorrect results.
The membrane cap is listed in the spare parts list.
Refill opening: if the sensor is used at excessive
temperatures or stored outside the storage bottle for
lengthy periods of time, this will result in electrolyte
evaporation losses.
If necessary, you should therefore unscrew the dia-
membrane head, remove the sealing screw, and ll
up the electrolyte using a syringe.
Then screw the sealing screw back in place.
11.4 Care and maintenance
If the sensor is not needed, it should be stored either
in the storage cap (lled with water) or directly in a
container full of deionised water.
If a bacterial, fungal or algae coating has formed on
the membrane, you should wipe o the coating using
a soft paper cloth prior to measurement.
If it is no longer possible to calibrate the sensor or if the
membrane is damaged, the sensor needs servicing.
Air bubbles in the membrane cap can aect measu-
rements. Please remove carefully.
! Exercise caution during maintenance work – the
electrolyte is caustic !
Wear disposable gloves when servicing the sensor and
wash your hands thoroughly with water afterwards.
Servicing the sensor:

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Unscrew the membrane head and wipe o the elec-
trolyte solution carefully using a paper cloth.
Do not allow the electrolyte to come into contact with
your hands. If it does come into contact with your skin,
rinse the aected area thoroughly in water.
To clean the silver cathode, sand lightly using sand-
paper (240 grit). Do not sand the silver cathode to a
smooth nish. It needs to be rough so that the electro-
lyte is distributed evenly. Carefully remove the sanding
dust after sanding.
Unscrew the rell screw and ll up carefully with elec-
trolyte until it just overows (disposable syringe). Screw
the rell screw back in place.
Fill new membrane cap with electrolyte, avoiding air
bubbles.
Screw the sensor vertically into the cap from above.
When you insert the sensor, the electrolyte is displaced
from the membrane head and overows.
Remove excess electrolyte using a paper cloth.
Turn the sensor upside down and check for air bubbles.
If there are no air bubbles, servicing is complete.
If air bubbles are still present, please remove carefully.
If the O-ring seal is damaged it needs replacing.
Important note: leave the sensor to settle for at least
1 hour before performing recalibration.
If it is still not possible to calibrate the sensor despite
servicing, the sensor needs to be checked at the fac-
tory and replaced if necessary.
12. Result memory
A maximum 20 results with the corresponding tempe-