ConOx
Operating manual
Combined Conductivity and Dissolved Oxygen Sensor
ba75383e03 10/2004
ConOx
Accuracy when
going to press
The use of advanced technology and the high quality standard of our
instruments are the result of continuous development. This may result in
differences between this operating manual and your instrument. Also, we
cannot guarantee that there are absolutely no errors in this manual.
Therefore, we are sure you will understand that we cannot accept any legal
claims resulting from the data, figures or descriptions.
26
Copyright
© Weilheim 2004, WTW GmbH
Reprinting - even as excerpts - is only allowed with the explicit written
authorization of WTW GmbH, Weilheim.
Printed in Germany.
ConOx Contents
ConOx - List of contents
1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
1.1 Structure and function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
1.2 Instrument identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
2 Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
3 Commissioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
3.1 Scopes of delivery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
3.2 Getting the sensor ready for measuring . . . . . . . . . . . . . . . . . .32
4 Measuring / Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
4.1 Calib ra t io n . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
4.2 Measu ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
4.3 Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34
5 Maintenance, cleaning, replacement . . . . . . . . . . . . . . . . . . 34
5.1 General maintenance instructions . . . . . . . . . . . . . . . . . . . . . . 34
5.2 Outside cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
5.3 DO module: Changing the electrolyte solution and
membrane cap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36
5.4 DO module: Cleaning the electrodes . . . . . . . . . . . . . . . . . . . .38
5.5 Checking the DO module for freedom from zero-current . . . . .40
5.6 Aging of the conductivity measuring cell . . . . . . . . . . . . . . . . . .40
5.7 Disposal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
6 What to do if... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
6.1 Error symptoms of DO measurement . . . . . . . . . . . . . . . . . . . . 42
6.2 Error symptoms of conductivity measuremen t . . . . . . . . . . . . .42
7 Technical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
7.1 Conductivity basic module . . . . . . . . . . . . . . . . . . . . . . . . . . . .43
7.2 Dissolved oxygen (DO) module . . . . . . . . . . . . . . . . . . . . . . . . 44
8 Wear parts and accessories . . . . . . . . . . . . . . . . . . . . . . . . . 47
27
Overview ConOx
1 Overview
1.1 Structure and function
The ConOx is a modular sensor for conductivity , dissolved oxygen (DO) and
temperature. It consists of two basic components:
l Conductivity basic module, according to the quadripole measuring princi-
ple, with integrated temperature sensor
l Removable dissolved oxygen module, according to the galvanic measur-
ing principle
Structure of the
ConOx
Conductivity basic module
41, 2 3 5
13
78961110 12
Dissolved oxygen (DO) module
1 Voltage electrode (inside, 2x)
2 Current electrode (ring, 2x)
3 Temperature sensor in a graphite enclosure
4 Shaft
5 Connection head
6 WP 90 membrane cap (filled with electrolyte solution)
7 Gold working electrode (cathode)
8 Insulator
9 Lead counter electrode (anode)
10 Screw thread base with ventilation area
11 Cap nut
12 Plug connection
13 Closing cap for conductivity basic module
14 Closing cap for DO module
14
28
ConOx Overview
The conductivity basic module can be used as an independent conductivity
measuring cell. For this pu rpose, unscrew the DO module and cl ose the open
plug connection with a closing cap.
The DO module is connected to the conductivity basic module via a watertight, three-pole plug connection. The conduc tivity basic module measures
the temperature, which is required for the determination of the DO content.
For this reason the DO module only works in conjuncti on with the conductivity
basic module.
Recommended
fields of
application
Conductivity basic
module
Dissolved oxygen
(DO) module
l On site measurements in rivers, lakes and wastewater
l fishfarming
l Ground water measurements
l Applications in water laboratories
1.2 Instrument identification
A series number is printed on both ConOx modules. Keep these numbers
ready if you have questions to ask the WTW service department.
The series numbers contain the following information:
The number is printed on the shaft.
12 3
03360013
The number is printed on the cap nut.
1234
0342A007
1 Manufacturing year 20... (example: 2003)
2 Calendar week of manufacturing (CW 36)
3 Sequential batch number (0013)
1 Manufacturing year 20... (example: 2003)
2 Calendar week of manufacturing (CW 42)
3 Sensor type (type A)
4 Sequential batch number (007)
29
Safety ConOx
2Safety
This operating manual contains special instructions that must be followed
during the operation of the sensor.
Always keep this operating manual in the vicinity of the sensor.
Special user
qualifications
General safety
instructions
The membrane cap of the DO module is filled with a small amount of an
alkaline electrolyte solution. All maint enance work t hat requi res deali ng wit h
the electrolyte soluti on must only be carr ied out by persons who know how to
deal with chemicals safely.
The individual chapters of thi s operating manual use safety labels like the one
below to indicate danger:
Caution
indicates instructions t hat must b e followed pr ecisely in orde r to avoid
slight injuries or damage to the instrument or the environment.
3 Commissioning
3.1 Scopes of delivery
3.1.1 Scope of delivery of the ConOx
l ConOx combination conductivity and DO sensor,
DO module filled with electrolyte soluti on and ready to use
l 1 closing cap for conductivity basic module
l 1 closing cap for DO module
l 3 exchange membrane caps, WP 90
l Calibration and storage vessel, OxiCal
l Polishing strip, SF 300
l Electrolyte solution, ELY/G
l Cleaning solution, RL/G
l Operating manual for ConOx
Note
The membrane cap that is mounted on the DO sensor for delivery serves
mainly as a transport protection. Depending on the duration of the transport
and storage period, it may have a shortened oper ational lifetime. If the measuring system cannot be calibrated (error message on the ins trument),
please proceed according to section secti on 5.3 DO
ELECTROLYTE SOLUTION AND MEMBRANE CAP.
®
-CX
MODULE: CHANGING THE
30
ConOx Commissioning
3.1.2 Scope of delivery of the conductivity basic module
l Conductivity basic module
l 1 closing cap, mounted on the conductivity basic module
l Operating manual for ConOx
3.1.3 Scope of delivery of the DO module
l DO module, filled with electrolyte solutio n and operabl e
l 1 closing cap, mounted on the DO module
l 1 exchange membrane cap, WP 90
l Polishing strip, SF 300
l Electrolyte solution, ELY/G
l Cleaning solution, RL/G
l Operating manual for ConOx
Note
The membrane cap that is mounted on the DO sensor for delivery serves
mainly as a transport protection. Depending on the duration of the transport
and storage period, it may have a shortened operati onal lifetime. If the measuring system cannot be calibrated (error message on the instr ume nt),
please proceed according t o s ection sec tion 5.3 DO
ELECTROLYTE SOLUTION AND MEMBRANE CAP.
MODULE: CHANGING THE
31
Commissioning ConOx
3.2 Getting the sensor ready for measuring
3.2.1 M easurements with the conductivity basic module
Make sure that the plug connection is tight ly closed by the closing cap. When
mounted, the closing cap (1) must be screwed on up to the stop.
12
Before screwing on the closing cap, check the following points:
l The sealing (2) must be clean and evenly positioned in the groove.
l The plug connection and the inside of the closing cap must be clean.
Screwing on the
DO module
3.2.2 M easurements with the combination sensor
Make sure that the DO module and conductivity basic module are screwed
together tightly. When mounted, the cap nut of the DO module has to be
screwed on up to the stop.
21 3
Before screwing on the DO module, check the following points:
l The sealing (3) must be clean and evenly positioned in the groove.
l The plug connection must be dry on both sides.
Position the DO module (1) on the conductivity basic module and carefully
and with slight pressure turn it until th e guidi ng nib on the DO module locks
in place in the corresponding groove on the conductivity basic module.
Subsequently tighten the cap nut (2) up to the stop. The thread onl y snatches
if the DO module was correctly positioned.
32
ConOx Measuring / Operation
Unscrewing the
DO module
Unscrew the cap nut and remove the DO module from the conducti vity basic
module.
Caution
Inappropriate handling can lead to the release of electrolyte solution.
When unscrewing the DO module only turn the cap nut (not the
membrane cap!).
3.2.3 Preparing the measuring operation
Connect the sensor to th e measur ing i nstr ument. The sen sor is immediatel y
ready to measure. It is not necessary to polarize the DO module.
4 Measuring / Operation
4.1 Calibration
To calibrate for DO measurements, use the OxiCal®-CX calibration and
storage vessel. If the A 325/K or A 325/S armoring is used, you have to
remove the protective hood and fixing nut of the armoring first.
Minimum
approach flow for
DO measurements
When determining the cell constant, observe the respective minimum
immersion depth with the closing cap or D. O. module screwed on (important:
the temperature sensor must be submersed). The minimum immersion
depths are given in chapter 7 T
ECHNICAL DATA.
Note
Please read the course of the calibration in the operating man ual of the measuring instrument.
4.2 Measuring
Please always observe the required minimum immersion depth and the
minimum approach flow that is important for DO measurements (see
chapter 7 T
The minimum flow can be provided in different ways, e. g.:
l The flow of the water to be measured is sufficient (aeration tank, water
pipe, stream)
l Slowly pull the sensor through the water by hand (lake, container), or
l Use a flow aid, e. g. a magnet ic st irr er wit h s tirr ing dev ic e or a batt ery s tir-
rer (see chapter 8 W
ECHNICAL DATA).
EAR PARTS AND ACCESSORIES)
Note
When using the BR 325 battery stirrer, please make sure that the protective
pipe already has the groove in the area of the conductivity basic module ( from
the year of manufacture, 2004).
33
Maintenance, cleaning, replacement ConOx
4.3 Storage
Always store the sensor with the DO module in the calibration vessel at a
temperature of 0 to +50 °C. Make sure that the sponge in the calibration vessel is always moist.
Storage in th e
calibration vessel,
®
OxiCal
-CX
12
Moisten the sponge:
l Remove the cap (1).
l Take out the sponge (2), wet it, then slightly squeeze it out.
l Reinsert the sponge and close the calibration vessel with the cap.
5 Maintenance, cleaning, replacement
5.1 General maintenance instructions
For your safety Note the following safety instru ctions when handling elect rolyte and cleaning
solutions:
Caution
The ELY/G electrolyte solution irritates eyes and skin. When dealing
with the ELY/G electrolyte solution, observe the following points:
l During working activities, always wear suitable protective gloves
and protective goggles/face shield.
l If it comes into contact with the ski n, rinse thoroughly with water and
immediately change contaminated clothing.
l If it comes into contact with the eyes, rinse thoroughly with water
and consult a doctor.
l Follow the safety datasheet.
34
ConOx Maintenance, cleaning, replacement
Caution
The RL/G cleaning solution irritates eyes and skin. When dealing with
the RL/G cleaning solution, observe the following points:
l During working activities, always wear suitable protective gloves
and protective goggles/face shield.
l If it comes into contact with the ski n, rinse thoroughly with water and
immediately change contaminated clothing.
l If it comes into contact with the eyes, rinse thoroughly with water
and consult a doctor.
l Follow the safety datasheet.
Caution
Before all maintenance activities, disconnect the sensor from the
instrument.
Note
Information on how to order wear parts and maintenance means can be
found in chapter 8 W
EAR PARTS AND ACCESSORIES.
Maintenance
activities on the
DO module
Cleaning agents
For better handling, l eave the DO modul e screwed on the conduc tivi ty basi c
module. Thus, you can better immerse the sensor head in the electrolyte or
cleaning solution and the plug connection remains prot ected against
damage.
5.2 Outside cleaning
Contamination Cleaning procedure
Lime sediments Immerse in acetic acid for 1 minute ( vol ume
share = 20 %)
Fat/oil Clean with warm water that contains
washing-up liquid
After cleaning, thoroughly rinse with deionized water and recalibrate if
necessary.
35
Maintenance, cleaning, replacement ConOx
5.3 DO module: Changing the electrolyte solution and
membrane cap
Caution
Before starting to work with the sensor, please note the GENERAL
MAINTENANCE INSTRUCTIONS on page 34.
General
information
WTW delivers the DO module ready to use (see section 3). The electrolyte
solution and the membrane cap must only be replaced if:
l a calibration error occurs and the membrane is heavily contaminated
l the membrane is damaged
l the electrolyte solution is exhausted.
Changing the electrolyte solution and membrane cap
Unscrew the membrane cap.
Caution:
Electrolyte solution!
Rinse the sensor head with
deionized water.
For disposal of the membrane
cap and electrolyte solution,
see section 5.7.
Carefully rub and dry the
counter electrode with a lintfree paper towel.
RL/G H O
Immerse the sensor head including the counter electrode
in RL/G cleaning solution.
Allow to react for 1 to 3 minutes.
36
Thoroughly rinse the sensor
head with deionized water.
2
Water the counter electrode in
deionized water for at least
10 minutes.
ConOx Maintenance, cleaning, replacement
ELY/G
Carefully shake off the drops
of water.
ELY/G
Thoroughly rinse the sensor
head with electrolyte solution.
Fill a new membrane cap with
ELY/G electrolyte solution.
Ventilation area
points upwards
Hold the sensor inclined and
screw on the membrane cap
fingertight using a paper towel. Excess electrolyte solut ion
is forced out of the ventilation
area.
Remove any air bubbles by
carefully tapping the membrane cap. Additionally, you
can prevent air bubbles by
throwing the first filling away
and refilling the membrane
cap.
4mm
Check the filling:
Inspect the face surface. No
air bubbles may be present
within the dashed circle. Air
bubbles outside this area do
not interfere.
Note
For measurements under high pressure the filling must be completely free of air bubbles.
Readiness to measure The DO module is ready for operation after approx. 30 to 50 min-
utes. Subsequently calibrate the sensor for DO measurements.
Note
If you want to measure very low DO concentrations (< 0.5 % saturation), we recommend to let the sensor rest overnight and then
calibrate it.
37
Maintenance, cleaning, replacement ConOx
5.4 DO module: Cleaning the electrodes
Caution
Before starting to work with the sensor, please note the GENERAL
MAINTENANCE INSTRUCTIONS on page 34.
General
information
Cleaning the electrodes
Unscrew the membrane cap.
Caution:
For disposal of the membrane
cap and electrolyte solution,
see section 5.7.
Electrolyte solution!
Cleaning is only required in cases of slopes too small or too large (sensor
cannot be calibrated) that cannot be resolved by changing the membrane cap
and electrolyte solution.
Rinse the sensor head with
deionized water.
SF 300
Using the rough side of the
wet SF 300 polishing strip,
polish off any contamination
from the gold working electrode using light pressure.
Caution:
ventional sandpaper or glassfiber brushes.
Do not use any con-
Rinse the sensor head with
deionized water.
38
Wipe the counter electrode
with a lint-free paper towel
and carefully remove any
loose white deposits.
RL/G
Immerse the sensor head including the counter electrode
in RL/G cleaning solution.
Allow to react for 1 to 3 minutes.
ConOx Maintenance, cleaning, replacement
H O
2
Thoroughly rinse the sensor
head with deionized water.
ELY/G
Fill a new membrane cap with
ELY/G electrolyte solution.
Water the counter electrode in
deionized water for at least
10 minutes.
Remove any air bubbles by
carefully ta pp ing the membrane cap. Additionally, you
can prevent air bubbles by
throwing the first filling away
and refilling the membrane
cap.
Carefully shake off the drops
of water.
ELY/G
Rinse the sensor head with
electrolyte solution.
Ventilation area
points upwards
Hold the sensor inclined and
screw on the membrane cap
fingertight using a paper towel. Excess electrolyte soluti on
is forced out of the vent il ation
area.
4mm
Check the filling:
Inspect the face surface. No
air bubbles may be present
within the dashed circle. Air
bubbles outside this area do
not interfere.
39
Maintenance, cleaning, replacement ConOx
Note
For measurements under high pressure the filling must be completel y free of
air bubbles.
Readiness to
measure
After approx. 30 to 50 minutes, the sensor is ready for operation. Subsequently calibrate the sensor.
Note
If you want to measure ver y l ow DO concen trati ons (< 0.5 % saturation), we
recommend to let the sensor rest overnight and then calibrate it.
5.5 Checking the DO module for freedom from zero-current
The DO module is free from zero-current. Checking the module for fr eedom
from zero-current is only necessary in the case of malfunctions that cannot
be remedied by exchanging the e lectrolyte soluti on and membrane cap or by
cleaning the electrodes.
There are two possibilities to check the DO module for freedom from zerocurrent:
l Measurement in a nitrogen atmosphere (recommended method)
l Measurement in a sodium sulfite soluti on according to DIN EN 25814/
ISO 5814.
Caution
If you check the sensor according to DIN EN 25814/ISO 5814, do not
leave the sensor in the sodium sulfite soluti on for more than 2 minutes.
Danger of sensor poisoning!
Test criterion The DO module is OK if the measuring instrument displays < 1 % DO
saturation after 2 minutes.
5.6 Aging of the conductivity measuring cell
Normally, the conductivity measuring cel l does not age. Special measuring
media (e.g. strong acids and ly es, organic solvents) or too high temperatures
shorten the operational lifeti me considerably or damage the measuring cell.
The warranty does not cover cases where such conditions cause failure or
mechanical damage.
40
ConOx Maintenance, cleaning, replacement
5.7 Disposal Caution
The ELY/G electrolyte solution irritates eyes and skin. When dealing
with the ELY/G electrolyte solution, observe the following points:
l During working activities, always wear suitable protective gloves
and protective goggles/face shield.
l If it comes into contact with the ski n, rinse thoroughly with water and
immediately change contaminated clothing.
l If it comes into contact with the eyes, rinse thoroughly with water
and consult a doctor.
l Follow the safety datasheet.
Conductivity basic
module, DO
module and
membrane cap
Electrolyte
solution
For disposal, unscrew the membrane cap from the DO module. Then rinse
the entire sensor and the membrane cap with water.
We recommend to dispose of the conductivity basic module and the DO
module without membrane cap as electronic waste. The membrane cap may
be disposed of with the household refuse.
Disposal according to the safety data sheet.
41
What to do if... ConOx
6 What to do if...
6.1 Error symptoms of DO measurement
Error symptom Cause Remedy
The sensor is in the air
and the display shows
0.0 mg/l or 0 % O
The sensor cannot be
calibrated
2
– No connection between
measuring instrument and sensor
– Cable defective
– No electrolyte in the membrane
cap
– Contaminated membrane cap
– Electrolyte depleted
– Check connection between
measuring instrument and sensor
– Replace and refill the membrane
cap (see section 5.3)
– Replace and refill the membrane
cap (see section 5.3)
Subsequently, wait for 30 to
50 min and recalibrate.
The sensor still cannot
be calibrated after
changing the electrolyte
and membrane cap
Incorrect temperature
display
Mechanical damage to
the sensor
– Contaminated electrodes or
sensor toxification
– membrane cap not screwed on
tight enough
– The temperature sensor of the
conductivity basic module was not
immersed deep enough in the
measuring solution
– Temperature sensor defective
– Clean the electrodes (see
section 5.4)
– Screw membrane cap tighter
– Observe the minimum immersion
depth
– Return the sensor
– Return the sensor
6.2 Error symptoms of conductivity measurement
Error symptom Cause Remedy
No temperature or conductivity display
– No connection between
measuring instrument and sensor
– Cable defective
– Check connection between
measuring instrument and sensor
Measurement delivers
implausible conductivity
values
Incorrect temperature
display
42
– Incorrect cell constant adjusted at
the measuring instrument
– Measuring range exceeded
– Contamination in the area of the
electrodes
– Electrodes damaged
– The temperature sensor was not
immersed deep enough in the
measuring solution
– Temperature sensor defective
– Check / correct the cell constant
– Observe the application range
– Clean the sensor (see
section 5.2).
– Return the sensor
– Observe the minimum immersion
depth
– Return the sensor
ConOx Technical data
7 Technical data
7.1 Conductivity basic module
General features Measuring principle Four-electrode measurement
Cell constant 0.475 cm
-1
±1.5 %
Temperature sensor integrated NTC 30 (30 k
Dimensions
(in mm)
Weight approx. 135 g (without DO module, with 1.5 m cable)
Materials Shaft Epoxy
– Connection head POM
– Closing cap PVC
Plug connection for
DO module
Conductivity electrodes Graphite
PEEK
W/ 25 °C)
Thermistor enclosure Graphite
Connection cable Lengths 1.5 / 3 / 6 / 10 / 15 / 20 m
Diameter 6 mm
Connector for DO
module
Smallest allo w e d
bend radius
Plug type Socket, 8 pins
Plug type 3-pole, watertight plug connection with cap
Permanent bend: 80 mm
Single time or short time bend:50 mm
nut, reverse polarity protected, contacts
gold-plated
43
Technical data ConOx
Pressure
resistance
Measurement
conditions
Storage
conditions
Sensor with closed plug
IP 68 (3 x 105Pa or 3 bar)
connection
Cable plug IP 67 (when plugged in)
The ConOx meets the requirements according to article 3(3) of the
97/23/EC directive ("Pressure equipment directive").
Conductivity measuring
mS/cm ... 2 S/cm
1
range
Temperature range 0 ... 50 °C
Max. allowed overpressure 3 x 10
5
Pa (3 bar)
Depth of immersion min. 6 cm (with closing cap)
min. 8 cm (with DO module)
max. 20 m (depending on the cable length)
Operating position any
Approach flow not required
®
Recommended storing
method
in the OxiCal
ened)
-CX calibration vessel (moist-
or dry (without DO module)
Storage temperature 0 ... 50 °C
Characteristic data
on delivery
Temperature responding
behavior
Precision of the temperature
(99 % of the final value display after)
t
99
<20s
±0.3K
sensor
7.2 Dissolved oxygen (DO) module
General features Measuring principle Membrane covered galvanic sensor
Temperature compensation
Dimensions
(in mm)
IMT compensation
(calculated by the measuring instrument)
44
Weight approx. 20 g (filled with electrolyte)
ConOx Technical data
Materials Working electrode Gol d
Counter electrode Lead
– Membrane cap
POM
– Cap nut
Membrane FEP, 13
µm
– Sensor head Epoxy, PEEK
– Plug connection PEEK
Screw thread base Stainless steel 1.4571
Seals FPM (Viton)
Closing cap POM
Plug connection Plug type 3-pole, watertight plug connection with cap nut,
reverse polarity protected, contacts gold-plated
Pressure
resistance
Sensor with closed plug
connection
IP 68 (3 x 10
5
Pa or 3 bar)
The DO module meets the requirements according to article 3(3) of the 97/
23/EC directive ("Pressure equipment directive").
Measurement
conditions
Measuring ranges at
20 °C
0 ... 50 mg/l DO
0 ... 600 % DO satu ra tion
0 ... 1250 mbar DO partial pressure
Polarization time mi n. 30 ... 50 min after changing the electrolyt e,
it is not necessary to con nect the sensor to t he
measuring instrument for polarization
Storage
conditions
Temperature range 0 ... 50 °C
5
Max. allowed overpres-
3 x 10
Pa (3 bar)
sure
Depth of immersion with
conductivity basic module
min. 8 cm
max. 20 m (depending on the cable length of
the conductivity basic module)
Operating position any
Approach flow > 3 cm/s at 10 % measurement accuracy
10 cm/s at 5 % measurement accuracy
18 cm/s at 1 % measurement accuracy
®
Recommended storing
method
in the OxiCal
ened)
-CX calibration vessel (moist-
Storage temperature 0 ... 50 °C
45
Technical data ConOx
Characteristic data
on delivery
Pin assignment
Zero signal < 0.1 % of the saturation value
Response time at 20 °Ct
Oxygen own consumption
(90 % of the final value display after) < 10 s
90
(95 % of the final value display after) < 16 s
t
95
(99 % of the final value display after) < 60 s
t
99
0.008
µg·h
-1
(mg/l)
-1
at 20 °C
Drift approx. 3 % per month in the operating condi-
tion
Working life min. 6 months with one electrolyte filling
Conductivity basic moduleDO module
Current electrode 2
4
Voltage electrode 2
Plug connection:
AE
GE GE
GE
AE
Cod
AE
Shield
2
Voltage electrode 1
5
Current electrode 1
3
Counter electrode
8
Working electrode
6
Cod
NTC
30 kΩ
Shield+
wire
Plug from the front:
1
NTC
NTC
7
2
5
7
4
1
8
3
6
46
ConOx Wear parts and accessories
8 Wear parts and accessories
Wear parts and
maintenance
Description Model Order no.
Set of exchange membrane caps (3 pieces) WP 90/3 202 725
means
Electrolyte solution ELY/G 205 217
Cleaning solution for lead counter electrode RL/G 205 204
Polishing film SF 300 203 680
Accessory kit, comprising:
ZBK 325 202 706
– 3 exchange membrane caps, WP 90
– Polishing strip, SF 300
– Electrolyte solution, ELY/G
– Cleaning solution, RL/G
Spare parts set, comprising:
ACC/CX 401 080
– 1 closing cap for conductivity basic
module
– 1 closing cap for DO module
– O-ring grease for the sealings of the
closing caps
®
– Sponge + lid for OxiCal
-CX
– Sealing for plug connection
Accessories Description Model Order no.
®
Calibration and storage vessel OxiCal
-CX 205 400
Magnetic stirrer Oxi-Stirrer 300 203 810
Stirring accessory - p rovi des a constant, de-
RZ 300 203 824
fined flow of the sensor, in conjunction with
the Oxi-Stirrer 300
Plastic armoring with protective hood A 325/K 903 830
Steel armoring with protective hood A 325/S 903 831
Special protective hood against fish biti ng -
SK-325 201 580
only in conjunction with A 325/K or A 325/S
Battery stirrer fo r depth measurements - only
BR 325 203 826
in conjunction with A 325/K or A 325/S
Note
For further accessories, refer to the WTW catalog or the Internet.
47
Wear parts and accessories ConOx
48
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