Endress+Hauser Memosens COS51E User manual

Products Solutions Services
Operating Instructions
Memosens COS51E
Amperometric oxygen sensor with Memosens 2.0
technology
BA02146C/07/EN/02.22-00
71556090
2022-01-19

Memosens COS51E Table of contents
Endress+Hauser 3
Table of contents
1 About this document ................ 4
1.1 Warnings ............................ 4
1.2 Symbols used .......................... 4
1.3 Supplementary documentation ............. 5
2 Basic safety instructions ............ 6
2.1 Requirements for the personnel ............ 6
2.2 Intended use .......................... 6
2.3 Workplace safety ....................... 6
2.4 Operational safety ...................... 6
2.5 Product safety ......................... 7
3 Product description ................. 8
3.1 Product design ......................... 8
3.2 Measuring principle ..................... 9
3.3 Potentiostatic three-electrode system ........ 9
3.4 Membrane body ....................... 9
3.5 Polarization ........................... 9
3.6 Memosens technology ................... 9
4 Incoming acceptance and product
identification ..................... 11
4.1 Incoming acceptance ................... 11
4.2 Product identification ................... 11
4.3 Scope of delivery ...................... 12
5 Mounting ......................... 13
5.1 Mounting requirements ................. 13
5.2 Mounting the sensor ................... 14
5.3 Installation examples ................... 16
5.4 Post-mounting check ................... 21
6 Electrical connection .............. 22
6.1 Connecting the sensor .................. 22
6.2 Ensuring the degree of protection .......... 22
6.3 Post-connection check .................. 22
7 Commissioning .................... 23
7.1 Function check ....................... 23
7.2 Sensor polarization and preparation for
calibration/adjustment ................. 23
7.3 Calibration and adjustment .............. 24
8 Diagnostics and troubleshooting ... 28
8.1 Checking the sensor .................... 28
8.2 General troubleshooting ................. 28
9 Maintenance ...................... 30
9.1 Maintenance schedule .................. 30
9.2 Maintenance tasks ..................... 30
10 Repair ............................ 34
10.1 General notes ........................ 34
10.2 Return .............................. 34
10.3 Spare parts and consumables ............. 34
10.4 Checking the measurement function ....... 38
10.5 Disposal ............................ 38
11 Accessories ....................... 39
11.1 Device-specific accessories ............... 39
12 Technical data .................... 42
12.1 Input ............................... 42
12.2 Power supply ......................... 42
12.3 Performance characteristics .............. 42
12.4 Environment ......................... 43
12.5 Process ............................. 43
12.6 Mechanical construction ................ 44
Index .................................. 46

About this document Memosens COS51E
4 Endress+Hauser
1 About this document
1.1 Warnings
Structure of information Meaning
LDANGER
Causes (/consequences)
If necessary, Consequences of
non-compliance (if applicable)
‣Corrective action
This symbol alerts you to a dangerous situation.
Failure to avoid the dangerous situation will result in a fatal or serious
injury.
LWARNING
Causes (/consequences)
If necessary, Consequences of
non-compliance (if applicable)
‣Corrective action
This symbol alerts you to a dangerous situation.
Failure to avoid the dangerous situation can result in a fatal or serious
injury.
LCAUTION
Causes (/consequences)
If necessary, Consequences of
non-compliance (if applicable)
‣Corrective action
This symbol alerts you to a dangerous situation.
Failure to avoid this situation can result in minor or more serious injuries.
NOTICE
Cause/situation
If necessary, Consequences of
non-compliance (if applicable)
‣Action/note
This symbol alerts you to situations which may result in damage to
property.
1.2 Symbols used
Symbol Meaning
Additional information, tips
Permitted or recommended
Not permitted or not recommended
Reference to device documentation
Reference to page
Reference to graphic
 Result of a step
1.2.1 Symbols on the device
Symbol Meaning
Reference to device documentation
Do not dispose of products bearing this marking as unsorted municipal
waste. Instead, return them to the manufacturer for disposal under the
applicable conditions.

Memosens COS51E About this document
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1.3 Supplementary documentation
The following manuals which complement these Operating Instructions can be found on
the product pages on the Internet:
• Technical Information for the relevant sensor
• Operating Instructions for the transmitter used
• Operating Instructions for the cable used
• Safety data sheet for the relevant electrolyte solutions
In addition to these Operating Instructions, an XA with "Safety instructions for electrical
apparatus in the hazardous area" is also included with sensors for use in the hazardous
area.
‣Please follow instructions on use in the hazardous area carefully.

Basic safety instructions Memosens COS51E
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2 Basic safety instructions
2.1 Requirements for the personnel
• Installation, commissioning, operation and maintenance of the measuring system may
be carried out only by specially trained technical personnel.
• The technical personnel must be authorized by the plant operator to carry out the
specified activities.
• The electrical connection may be performed only by an electrical technician.
• The technical personnel must have read and understood these Operating Instructions
and must follow the instructions contained therein.
• Faults at the measuring point may only be rectified by authorized and specially trained
personnel.
Repairs not described in the Operating Instructions provided must be carried out only
directly at the manufacturer's site or by the service organization.
2.2 Intended use
The sensor is suitable for continuous measurement of dissolved oxygen in aqueous
solutions.
The sensor is particularly suitable for:
• Measuring, monitoring and regulating the oxygen content in activated sludge basins
• Monitoring the oxygen content in the wastewater treatment plant outlet
• Monitoring, measuring and regulating the oxygen content in public waters and fish
farming water
Use of the device for any purpose other than that described, poses a threat to the safety of
people and of the entire measuring system and is therefore not permitted.
The manufacturer is not liable for damage caused by improper or non-designated use.
2.3 Workplace safety
As the user, you are responsible for complying with the following safety conditions:
• Installation guidelines
• Local standards and regulations
• Regulations for explosion protection
Electromagnetic compatibility
• The product has been tested for electromagnetic compatibility in accordance with the
applicable international standards for industrial applications.
• The electromagnetic compatibility indicated applies only to a product that has been
connected in accordance with these Operating Instructions.
2.4 Operational safety
Before commissioning the entire measuring point:
1. Verify that all connections are correct.
2. Ensure that electrical cables and hose connections are undamaged.
3. Do not operate damaged products, and protect them against unintentional operation.
4. Label damaged products as defective.

Memosens COS51E Basic safety instructions
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During operation:
‣If faults cannot be rectified:
products must be taken out of service and protected against unintentional operation.
LCAUTION
Cleaning not switched off during calibration or maintenance activities
Risk of injury due to medium or cleaning agent!
‣If a cleaning system is connected, switch it off before removing a sensor from the
medium.
‣If you need to test the cleaning function while cleaning is in progress, wear protective
clothing, goggles and gloves or take other suitable measures to protect yourself.
2.5 Product safety
2.5.1 State-of-the-art technology
The product is designed to meet state-of-the-art safety requirements, has been tested, and
left the factory in a condition in which it is safe to operate. The relevant regulations and
international standards have been observed.

Product description Memosens COS51E
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3 Product description
3.1 Product design
1
3
4
5
6
7
8
9
2
10
A0046006
 1 Sensor structure
1 Memosens plug-in connection
2 Threaded connection NPT ¾"
3 Threaded connection G1
4 Sensor shaft
5 Protection guard
6 Cathode
7 Membrane
8 Electrolyte
9 Anode
11
12
13
14
7
8
9
10
A0046012
 2 Sensor head, sectional drawing
7 Membrane
8 Electrolyte
9 Anode
10 Reference electrode
11 Screw thread for protection guard
12 Sealing ring
13 Screw thread for membrane cap
14 Membrane cap
6
A0046014
 3 Sensor head, top view
6 Cathode
The sensor consists of the following functional units:
• Sensor shaft
• Sensor head with cathode, anode and reference electrode
• Membrane cap with electrolyte filling
• Protection guard
Please note the following:
• As an alternative to the protection guard, a spray head can be used for immersion
operation with cleaning.
• The membrane cap screwed onto the sensor head contains the electrolyte. The screw
plug seals off the membrane cap from the medium.
• The sensor is ready for use immediately.

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3.2 Measuring principle
3.2.1 Amperometric measuring principle
During amperometric oxygen measurement, oxygen molecules diffuse through the
membrane and are reduced to hydroxide ions (OH-) at the working electrode. At the
counter-electrode, silver is oxidized to silver ions (Ag+) (this forms a silver halide layer).
The associated release of electrons at the working electrode and absorption of electrons at
the counter-electrode causes a current to flow. Under constant conditions, this current
flow is proportional to the oxygen content of the medium. The current is converted in the
transmitter and indicated on the display as an oxygen concentration in mg/l, µg/l, ppm,
ppb or Vol%, ppmVol, raw value nA, as a saturation index in % SAT or as an oxygen partial
pressure in hPa.
3.3 Potentiostatic three-electrode system
The high-impedance, current-free reference electrode plays an important role. The
formation of the silver bromide or silver chloride layer at the anode causes the electrolyte's
bromide or chloride ions to be depleted. With conventional membrane-covered sensors
with a two-electrode system, this results in increased signal drift.
Not so with the three-electrode system:
The change in the bromide or chloride concentration is recorded by the reference electrode
and an internal regulator circuit keeps the working electrode at a constant potential. The
advantages are a much higher signal accuracy and significantly extended calibration
intervals.
3.4 Membrane body
The oxygen dissolved in the medium is transported to the membrane by the necessary
flow. The membrane is permeable for dissolved gases only. Other substances dissolved in
the liquid phase, e.g. ionic substances, will not penetrate through the membrane.
Therefore, medium conductivity has no impact on the measuring signal.
The sensor is shipped with a membrane body, which can be used for both measuring
ranges. The membrane is pretensioned at the factory and can be used immediately.
Electrolytes are measuring range-specific and cannot be mixed in a single application!
Also pay attention to the safety datasheet of the electrolyte
www.endress.com/downloads.
3.5 Polarization
When the sensor is connected to the transmitter, a fixed voltage is applied between the
working electrode and the counter-electrode. The resulting polarization current can be
identified on the transmitter by a reading that is initially high, but decreases over time.
The reading must be stable before the sensor can be calibrated and a reliable
measurement is possible.
3.6 Memosens technology
Sensors with Memosens protocol have an integrated electronics unit that stores calibration
data and other information. Once the sensor has been connected, the sensor data are
transferred automatically to the transmitter and used to calculate the measured value and
for Heartbeat Technology functions.
‣Call up the sensor data via the corresponding DIAG menu.

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Digital sensors can store measuring system data (among other types of data) in the sensor:
• Manufacturer data
• Serial number
• Order code
• Date of manufacture
• Digital sensor label
• Calibration data of the last eight calibrations including factory calibration with
calibration date and calibration values
• Serial number of the transmitter used to perform the last calibration
• Possibility to reset to factory calibration
• In the case of sensors with replaceable measuring elements, the number of calibrations
per measuring element and for the entire sensor
• Operating data
• Temperature application range
• Date of initial commissioning
• Hours of operation under extreme conditions
• Number of sterilizations and CIP cycles (with hygienic sensors)
All Memosens 2.0 E sensors offer these advantages with the latest Liquiline transmitter
software. All Memosens 2.0 sensors are backward compatible with previous software
versions and offer the usual Memosens benefits of the D generation.

Memosens COS51E Incoming acceptance and product identification
Endress+Hauser 11
4 Incoming acceptance and product
identification
4.1 Incoming acceptance
1. Verify that the packaging is undamaged.
 Notify the supplier of any damage to the packaging.
Keep the damaged packaging until the issue has been resolved.
2. Verify that the contents are undamaged.
 Notify the supplier of any damage to the delivery contents.
Keep the damaged goods until the issue has been resolved.
3. Check that the delivery is complete and nothing is missing.
 Compare the shipping documents with your order.
4. Pack the product for storage and transportation in such a way that it is protected
against impact and moisture.
 The original packaging offers the best protection.
Make sure to comply with the permitted ambient conditions.
If you have any questions, please contact your supplier or your local Sales Center.
4.2 Product identification
4.2.1 Nameplate
The nameplate provides you with the following information on your device:
• Manufacturer identification
• Order code
• Extended order code
• Serial number
• Safety information and warnings
• Certificate information
‣Compare the information on the nameplate with the order.
4.2.2 Product identification
Product page
www.endress.com/cos51e
Interpreting the order code
The order code and serial number of your product can be found in the following locations:
• On the nameplate
• In the delivery papers
Obtaining information on the product
1. Open www.endress.com.
2. Call up the site search (magnifying glass).
3. Enter a valid serial number.
4. Search.
 The product structure is displayed in a popup window.

Incoming acceptance and product identification Memosens COS51E
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5. Click on the product image in the popup window.
 A new window (Device Viewer) opens. All of the information relating to your
device is displayed in this window as well as the product documentation.
4.2.3 Manufacturer address
Endress+Hauser Conducta GmbH+Co. KG
Dieselstraße 24
D-70839 Gerlingen
4.3 Scope of delivery
The scope of delivery comprises:
• Ordered version of the sensor with protective cap (filled with tap water) to protect the
membrane
• Accessories set with the following contents:
• 2 replacement membrane caps
• Electrolyte, 1 bottle, 10 ml (0.34 fl.oz.)
• Seal set with 3 O-rings
• 6 polishing foils in 2 grit sizes
• Safety instructions for the hazardous area (for sensors with Ex approval)
• Brief Operating Instruction
• Optional: cleaning unit
• Optional: replacement caps
If you have any questions, please do not hesitate to contact the the Endress+Hauser sales
team.

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5 Mounting
5.1 Mounting requirements
5.1.1 Dimensions
171 6.7,9 ( 7)
14 5.75,9 ( 4)
191,9 (7.55)
Ø40 (1.57)
A0045976
 4 Dimensions in mm (inch)

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5.1.2 Orientation
135°45°
10° 170°
A0030544
 5 Permitted orientations
Recommended installation angle
Possible installation angle
Inadmissible installation angle
The sensor must be installed at an angle of inclination of 10˚ to 170˚ in an assembly,
holder or suitable process connection. Recommended angle: 45° to prevent the attachment
of air bubbles.
Inclination angles other than those mentioned are not permitted. Do not install the sensor
upside down.
Follow the instructions for installing sensors in the Operating Instructions for the
assembly used.
5.1.3 Mounting location
1. Choose a mounting location that is easy to access.
2. Ensure that upright posts and assemblies are fully secured and vibration-free.
3. Choose a mounting location with an oxygen concentration that is typical for the
application.
5.2 Mounting the sensor
5.2.1 Measuring system
A complete measuring system comprises:
• a Memosens COS51E oxygen sensor
• A transmitter, e.g. Liquiline CM44
• a measuring cable, e.g. CYK10
• optional: an assembly, e.g. immersion assembly CYA112 or retractable assembly
COA451
• optional: a CYH112 assembly holder
• optional: a cleaning unit with compressed air system
• optional: other protection guards (71096199)

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1
23
4
A0045977
 6 Example of a measuring system with Memosens COS51E
1 Oxygen sensor Memosens COS51E
2 Retractable assembly COA451
3 Measuring cable CYK10
4 Liquiline CM44
5.2.2 Installing at a measuring point
Install assemblies away from the basin on a solid base. Only the final stage of
assembly should be performed at the intended mounting location. Choose a mounting
location that ensures correct handling of the assembly (installation, operation,
maintenance).
Must be installed in a suitable assembly (depending on the application).
LWARNING
Electrical voltage
In the event of a fault, non-grounded metallic assemblies may be live and as such are not
safe to touch!
‣When using metallic assemblies and installation equipment, national grounding
provisions must be observed.
To fully install a measuring point with a flow assembly or retractable assembly, proceed in
accordance with the following steps:
1. Install the retractable or flow assembly (if used) in the process.
2. Install the oxygen sensor in the assembly
3. Connect the cable to the sensor and transmitter
4. Connect the water supply to the rinsing nozzles provided (if using an assembly with
cleaning function).
5. Supply power to the transmitter
To fully install a measuring point with a suspended or immersion assembly, proceed in
accordance with the following steps:
1. Install the oxygen sensor in the assembly
2. Connect the cable to the sensor and transmitter

Mounting Memosens COS51E
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3. Install the suspended or immersion assembly in the process
4. Supply power to the transmitter
NOTICE
Installation fault
Cable open circuit, loss of sensor due to cable separation, unscrewing of membrane cap in
the assembly!
‣For immersion operation, the sensor must be installed in an immersion assembly (such
as CYA112). Do not install the sensor freely suspended from the cable!
‣Avoid exerting excessive tensile force on the cable (e.g. through jerky pulling
movements).
‣Choose a mounting location that is easy to access for later calibrations.
‣Follow the instructions for installing sensors in the Operating Instructions for the
assembly used.
5.3 Installation examples
5.3.1 Retractable assembly COA451
The assembly is designed for installation on vessels and pipes. This requires the availability
of suitable process connections.
Install the assembly in a place with uniform flow conditions. The pipe diameter must be at
least DN 80.
5
3
4
1
2
3
A
A*
2
4
A0045980
 7 Permissible and impermissible sensor installation positions with retractable assembly
1 Ascending pipe, best position
2 Horizontal pipe, sensor top down, impermissible due to air cushion or foam bubble forming
3 Horizontal pipe, lateral installation with permissible installation angle (acc. to sensor version)
4 Upside-down installation, unsuitable
5 Down pipe, impermissible
A Detail A (top view)
A* Detail A, turned by 90° (side view)
Possible installation angle
Inadmissible installation angle
NOTICE
Sensor not fully immersed in the medium, buildup, upside-down installation
These can all cause incorrect measurements!
‣Do not install assembly at points where air pockets or bubbles may form.
‣Avoid buildup on the sensor membrane or remove it at regular intervals.
‣Do not install sensor upside down.

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5.3.2 Immersion operation
Universal holder and chain assembly
1
5
2
4
3
6
A0042857
 8 Chain holder on railing
1 Chain
2 Holder Flexdip CYH112
3 Rail
4 Basin rim
5 Oxygen sensor
6 Wastewater assembly Flexdip CYA112
1 2
3
6
4
5
7
A0042858
 9 Chain holder on upright post
1 Weather protection cover CYY101
2 Transmitter
3 Chain
4 Wastewater assembly Flexdip CYA112
5 Oxygen sensor
6 Basin rim
7 Holder Flexdip CYH112
Universal holder and fixed immersion tube
12
3
4
6
5
A0042859
 10 Assembly holder with immersion tube
1 Protective cover
2 Transmitter
3 Flexdip CYA112 immersion assembly
4 Oxygen sensor
5 Basin rim
6 Assembly holder Flexdip CYH112

Mounting Memosens COS51E
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Basin rim mounting with immersion tube
12
3
4
5
A0042860
 11 Basin rim mounting
1 Pendulum holder CYH112
2 Assembly Flexdip CYA112
3 Assembly float
4 Oxygen sensor
5 Basin rim
Float
The CYA112 float is for use in the case of large fluctuations in water level, for example in
rivers or lakes.
1
2
3
4
5
6
7
G1
800 (31.50)
500 (19.69) 220 (8.66)
Ø200 (7.87)
A0032159
 12 Dimensions in mm (inch)
1 Cable run with strain relief and rain shield
2 Fixing ring for rope and chains with terminal screw
3 Eyelets Ø15, 3 x 120 ° for anchoring
4 Plastic float, resistant to salt water
5 Pipe 40 x 1, stainless steel 1.4571
6 Bumper and ballast
7 Oxygen sensor
5.3.3 Flow assembly COA250
The COA250 flow assembly with automatic self-venting is suitable for use in pipelines or
at hose connections. The inlet is at the bottom of the assembly and the outlet is at the top
(G¾ connection thread). It is installed in a pipe using two 90° pipe brackets at the inlet of
assembly (item 6).

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A0013319
 13 COA250
1
23
4
6
7
8
5
A0030570
 14 Bypass installation with manually actuated valves or solenoid
valves
1 Main pipe
2 Medium return
3 Oxygen sensor
4, 7 Manually actuated or solenoid valves
5 Flow assembly COA250-A
6 90 ° pipe elbow
8 Medium removal
5.3.4 Universal flow assembly Flowfit CYA251
13
4
65
2
A0032917
 15 Measuring system with CYA251
1 Transmitter
2 Flow assembly
3 Medium outlet
4 Cap
5 Medium inflow
6 Memosens COS51E

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13
5
62
7
2
24
A0032920
 16 Connection diagram
1 Main pipe 5 Medium inflow
2 Manually actuated or solenoid valves 6 Flow assembly
3 Medium outlet 7 Medium removal
4 Medium return
Mount the sensor in the assembly in accordance with the Operating Instructions
(BA00495C).
There must be a minimum flow rate of 100 ml/h (0.026 gal/h).
‣Take increased response times into account.
As an alternative to bypass operation, direct the sample flow from a filter unit with an
open outlet through the assembly:
2
1
3
4
A0032921
 17 Flow assembly with open outlet
1 Pump
2 Assembly
3 Open outlet
3 Filter unit