Endress+Hauser CAS51D Operating Manual

BA00459C/07/EN/15.19 71447513 2019-01-31

Products Solutions Services

Operating Instructions

Viomax CAS51D

Photometric sensor for SAC or nitrate measurement

Table of contents Viomax CAS51D

1 About this document ................ 3

1.1 Warnings ............................ 3

1.2 Symbols used .......................... 3

1.3 Symbols on the device ................... 3

2 Basic safety instructions ............ 4

2.1 Requirements for the personnel ............ 4

2.2 Designated use ........................ 4

2.3 Workplace safety ....................... 4

2.4 Operational safety ...................... 5

2.5 Product safety ......................... 5

3 Device description .................. 6

3.1 Sensor design ......................... 6

3.2 Dimensions ........................... 6

3.3 Operating principle ..................... 8

4 Incoming acceptance and product

identification ..................... 11

4.1 Incoming acceptance ................... 11

4.2 Product identification ................... 11

4.3 Scope of delivery ...................... 12

4.4 Certificates and approvals ............... 12

10 Repairs ........................... 37

10.1 Return .............................. 37

10.2 Disposal ............................ 37

11 Accessories ....................... 38

11.1 Assemblies .......................... 38

11.2 Holder .............................. 38

11.3 Compressed air cleaning ................ 38

11.4 Standard solutions ..................... 39

12 Technical data .................... 40

12.1 Input ............................... 40

12.2 Performance characteristics .............. 41

12.3 Environment ......................... 42

12.4 Process ............................. 42

12.5 Mechanical construction ................ 42

Index .................................. 43

5 Mounting ......................... 13

5.1 Installation conditions .................. 13

5.2 Mounting the sensor ................... 14

5.3 Immersion operation ................... 15

5.4 Flow operation ....................... 17

5.5 Mounting the cleaning unit .............. 22

5.6 Post-installation check .................. 23

6 Electrical connection .............. 24

6.1 Connecting to the transmitter ............ 24

6.2 Ensuring the degree of protection .......... 25

6.3 Post-connection check .................. 25

7 Operation ......................... 26

7.1 Calibration .......................... 26

7.2 Cyclic cleaning ........................ 35

8 Diagnostics and troubleshooting ... 35

9 Maintenance ...................... 36

9.1 Maintenance intervals .................. 36

9.2 Cleaning the sensor .................... 36

9.3 Maintenance of optical filters and strobe

lamp ............................... 37

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Viomax CAS51D About this document

1 About this document

1.1 Warnings

Structure of information Meaning

DANGER

Causes (/consequences)

If necessary, Consequences of non-compliance (if applicable)

Corrective action

‣

WARNING

Causes (/consequences)

If necessary, Consequences of non-compliance (if applicable)

Corrective action

‣

CAUTION

Causes (/consequences)

If necessary, Consequences of non-compliance (if applicable)

Corrective action

‣

NOTICE

Cause/situation

If necessary, Consequences of non-compliance (if applicable)

Action/note

‣

This symbol alerts you to a dangerous situation. Failure to avoid the dangerous situation will result in a fatal or serious injury.

This symbol alerts you to a dangerous situation. Failure to avoid the dangerous situation can result in a fatal or serious injury.

This symbol alerts you to a dangerous situation. Failure to avoid this situation can result in minor or more serious injuries.

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

1.3 Symbols on the device

Symbol Meaning

Reference to device documentation

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Basic safety instructions Viomax CAS51D

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 Designated use

CAS51D is a photometric sensor for SAC or nitrate measurement in liquid media.

The sensor is particularly suited for use in the following applications:

• Monitoring and regulating water treatment plants

• Monitoring surface waters

SAC measurement

• Organic load in WWTP inlet

• Organic load WWTP outlet

• Discharger monitoring

• Organic load in drinking water

Nitrate measurement

• Nitrate measurement in natural bodies of water

• Monitoring nitrate content in WWTP outlet

• Monitoring nitrate content in aeration basins

• Monitoring and optimizing denitrification phases

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

CAUTION

UV light

UV light can damage the eyes!

Never look into the cuvette gap while the sensor is in operation.

‣

As the user, you are responsible for complying with the following safety conditions:

• Installation guidelines

• Local standards and regulations

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.

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Viomax CAS51D Basic safety 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.

During operation:

If faults cannot be rectified:

‣

products must be taken out of service and protected against unintentional operation.

2.5 Product safety

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.

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Device description Viomax CAS51D

(1.97)

40 (1.57)

388 (15.28)

78 (3.07)

NPT “¾

2 (0.08)

8 (0.31)

12 (0.47)

20 (0.79)

14.5 (0.57)

NPT “¾

78 (3.07)

394 (15.51)

8 (0.31)

40 (1.57)

14 (0.55)

20 (0.79)

12 (0.47)

14.5 (0.57)

3 Device description

3.1 Sensor design

The sensor has a diameter of 40 mm and can be operated directly and completely in the process without the need for further sampling (in situ). One version of the sensor measures the amount of nitrate in the medium while another version measures the SAC value of the medium.

The sensor comprises the following assemblies:

• Power supply

• High-voltage generation for the strobe lamp,

• Cuvette Central component in which the measuring light interacts with the medium.

• Receiver assembly Detect the measuring signals, digitize them and process them to form a measured value.

• Controller Responsible for controlling internal sensor processes and transmitting data.

All data - including the calibration data - are stored in the sensor. The sensor can be precalibrated and used at a measuring point, calibrated externally, or used for several measuring points with different calibrations.

3.2 Dimensions

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 1 Sensor with 2 mm gap width, dimensions in

mm (inch)

A0013193

 2 Sensor with 8 mm gap width, dimensions in

mm (inch)

A0013208

Viomax CAS51D Device description

20 (0.79)

12 (0.47)

14.5 (0.57)

40 (1.57)

NPT “¾

69 (2.72)

40 (1.57)

46 (1.81)

426 (16.77)

A0031311

 3 Sensor with 40 mm gap width, dimensions in

mm (inch)

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Device description Viomax CAS51D

3.3 Operating principle

3.3.1 Measuring principle

The light from a pulsed, high-stability strobe lamp (item 3) passes through the measuring

path 1 and 5). A filter upstream from the receivers only lets through light in the measuring wavelength or reference wavelength.

(item 2). A beam splitter (item 6) directs the light beam to the two receivers (items

A0013213

 4 Measuring principle of nitrate sensor

1 Measuring receiver with filter 2 Cuvette gap 3 Strobe lamp 4 Lens 5 Reference receiver with filter 6 Beam splitter

Within the measuring path, the medium in the cuvette (water, dissolved substances and particles) absorbs light across the entire spectrum. In the measuring wavelength range, the measured component

takes an additional amount of energy from the light.

For the calculation of the measured value, the ratio of the light signal of the measuring wavelength to the light signal of the reference wavelength is calculated in order to minimize the effect of turbidity and lamp aging.

This change in the ratio can be converted to determine the nitrate concentration or the SAC value. This dependency is non-linear.

Conclusion:

• Long measuring paths are required for low concentrations of the measured component. For clear water measurements, this is achieved with the 8 mm cuvette for nitrate measurement and the 40 mm cuvette for SAC measurement.

• For high turbidity values, longer measuring paths result in the total absorption of light the measured values are no longer valid. The nitrate sensor with the 2 mm cuvette is recommended for media with high turbidity values (activated sludge application). The SAC sensor with the 2 mm cuvette is ideal for measuring the organic load in the inlet of municipal wastewater treatment plants.

1) Measuring path = open path through cuvette

2) Nitrate or substances that contribute to the spectral absorption coefficient (SAC)

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Viomax CAS51D Device description

3.3.2 Nitrate measurement

The sensor is designed for measuring nitrate. As nitrite is also measured, it could also be regarded as an NOx sensor.

Nitrate ions absorb UV light in the range of approx. 190 to 230 nm. Nitrite ions have a similar absorption rate in the same range.

The sensor measures the light intensity of the 214 nm wavelength (measuring channel). At this wavelength, nitrate and nitrite ions absorb light in proportion to their concentration, while the light intensity in the reference channel remains virtually unchanged at 254 nm.

Interference factors, such as turbidity, fouling or organic hydrocarbons, are minimized.

The signal ratio between the reference wavelength and measurement wavelength constitutes the measurement result. This ratio is converted to the concentration of nitrate using the calibration curve programmed into the sensor.

3.3.3 Cross-interference when measuring with the nitrate version

The following have a direct impact on the measuring range:

• Total solids (TS) and turbidity

• Sludge properties

• Nitrite

Trends:

• A higher proportion of TS or greater turbidity reduces the upper end of the measuring range, resulting in a smaller measuring range.

• High COD measuring range.

• Nitrite is measured as nitrate, thus resulting in a higher measured value.

The following can be deduced from the interdependencies cited above:

• Sludge floc causes scattering in the medium, resulting in the attenuation of both the measuring and reference signal to varying degrees. This in turn can bring about a change in the nitrate value due to turbidity.

• High concentrations of oxidizable substances in the measured value.

• Nitrite absorbs light in a similar wavelength range to nitrate and is measured along with nitrate. The dependency is constant: 1.0 mg/l nitrite is displayed as 0.8 mg/l nitrate.

• An adjustment to the customer process is always worthwhile.

levels reduce the upper end of the measuring range, resulting in a smaller

in the medium may result in an increase

3.3.4 SAC measurement

Many organic substances absorb light in the range of 254 nm. In the SAC sensor, absorption on the measuring wavelength (254 nm) is compared with the largely unaffected reference measurement at 550 nm.

KHP (potassium hydrogen phthalate C8H5KO4) is the established organic reference in SAC measurement operations. That is why the sensor is calibrated in the factory using KHP.

The SAC value can be regarded as a trend indicator of the organic load in a medium. For this purpose, it is converted to COD, TOC, BOD and DOC

factors: c (TOC) = 0.4705 * c (KHP) c (COD) = 1.176 * c (KHP) c (BOD) = 1.176 * c (KHP) c (DOC) = 0.4705 * c (KHP)

3) COD = Chemical Oxygen Demand

4) Specified as COD. Corresponds to the quantity of oxygen that would be required to oxidize the substances if oxygen were the oxidizing agent.

5) Chemical Oxygen Demand (COD), Total Organic Carbon (TOC), Biochemical Oxygen Demand (BOD), Dissolved Organic Carbon (DOC)

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using predefined, adjustable

Device description Viomax CAS51D

The ratio to SAC (based on KHP) is calculated as follows: 1/m = 1.487 mg/l COD = 1.487 mg/l BOD = 0.595 mg/l TOC = 0.595 mg/l DOC

Many components that absorb light at 254 nm deviate significantly from KHP in terms of their absorption behavior. For this reason, an adjustment to the customer process is worthwhile.

3.3.5 Cross-interference when measuring with the SAC version

The following have a direct impact on the measuring range:

• Turbidity

• Color

Trends:

• Oxidizable substances, absorbing at 550 nm, corrupt the measurement result. In instances of this nature, a comparison or calibration is necessary.

• Coloration that absorbs in the green spectral range increases the measured value.

• Oxidizable substances with spectral properties that differ to those of KHP (potassium hydrogen phthalate) provide measurement results that can deviate from the factory calibration. In instances of this nature, a comparison or adjustment is necessary.

• A higher proportion of TS or greater turbidity reduces the upper end of the measuring range, resulting in a smaller measuring range.

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Viomax CAS51D Incoming acceptance and product identification

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

• Extended order code

• Serial number

• Safety information and warnings

Compare the information on the nameplate with the order.

‣

4.2.2 Product identification

Product page

www.endress.com/cas51d

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. Go to 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.

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Incoming acceptance and product identification Viomax CAS51D

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.

Manufacturer's address

Endress+Hauser Conducta GmbH+Co. KG Dieselstraße 24 D-70839 Gerlingen

4.3 Scope of delivery

The delivery comprises:

• Sensor in the version ordered

• Operating Instructions

4.4 Certificates and approvals

4.4.1 

The product meets the requirements of the harmonized European standards. As such, it complies with the legal specifications of the EU directives. The manufacturer confirms successful testing of the product by affixing to it the  mark.

4.4.2 EAC version

The product has been certified according to guidelines TP TC 004/2011 and TP TC 020/2011 which apply in the European Economic Area (EEA). The EAC conformity mark is affixed to the product.

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Viomax CAS51D Mounting

5 Mounting

5.1 Installation conditions

5.1.1 Mounting location

Choose a mounting location that can be easily accessed at a later stage.

‣

Ensure that upright posts and fittings are fully secured and vibration-free.

‣

Select an installation location that produces a typical nitrate concentration / a typical

‣

SAC value for the application in question. Do not install the sensor above aeration discs. Oxygen bubbles may accumulate at the

‣

cuvette gap and distort the measured value.

5.1.2 Orientation

Align the sensor in such a way that the cuvette gap is

‣

rinsed with the flow of medium and air bubbles are removed.

A0013268

 5 Sensor orientation, arrow =

direction of flow

Flexdip CYA112 wastewater assembly and Flexdip CYH112 holder

A0013267

 6 Horizontal, fixed installation

The installation angle is 90°.

Align the sensor in such a way that the

‣

cuvette gap is rinsed with the flow of medium and air bubbles are removed.

 7 Suspended vertically from a chain

The installation angle is 0°. Tried and tested arrangement for operation in aerated zones.

Ensure that the sensor is adequately

‣

cleaned. There must be no buildup on the optical windows.

A0013270

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Mounting Viomax CAS51D

1 2

Flow assembly CAS51D 2-40 mm for small sample volumes

A0013266

 8 Horizontally, in flow assembly, arrow points in the direction of flow

1 Sensor 2 Flow assembly 3 Medium outlet 4 Medium inflow 5 Window, required for aligning the sensor

Flowfit CYA251 flow assembly

 9 Horizontally, in flow assembly CYA251, arrow points in the direction of flow

1 Sensor 2 Medium outlet 3 Cap 4 Flow assembly 5 Medium inflow 6 Rinse connection

A0032901

5.2 Mounting the sensor

5.2.1 Installation instructions

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To ensure correct measurement, the windows in the cuvette must be free from any sedimentation. The best way to ensure this is through the use of a cleaning unit (accessory) operated by compressed air.

For horizontal orientations:

‣

Mount the sensor in such a way that air bubbles can escape from the cuvette slot (do not point it downwards).

Viomax CAS51D Mounting

5.3 Immersion operation

5.3.1 Fixed installation with wastewater assembly

 10 Installation secured on railing

1 Wastewater assembly Flexdip CYA112 2 Flexdip CYH112 holder 3 Rail 4 Viomax CAS51D

A0013347

 11 Installation with upright post

1 Protective cover 2 Liquiline CM44x multi-channel transmitter 3 Wastewater assembly Flexdip CYA112 4 Viomax CAS51D 5 Flexdip CYH112 holder

A0013215

This type of installation is particularly suitable for strong or turbulent medium flow (>0.5 m/s (1.6 ft/s)) in basins or channels. A cleaning unit (accessory) operated by compressed air significantly extends the maintenance intervals for the sensor.

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