optek manual 1004 5003 02 calibration handbook vis nir us 2012-06-28

Calibration Handbook VIS-NIR

optek-Manual--1004-5003-02--Calibration-Handbook-VIS-NIR-US-2012-06-28.pdf

PN: 1004-5003-02 (-52)

optek-Danulat GmbH Emscherbruchallee 2 45356 Essen Germany Telefon: +49-201-63409-0 Fax: +49-201-63409-999 E-Mail: [email protected] Internet: www.optek.com

Preface

This handbook is written to assist the user in proper procedures for trouble-free operation.

It is explicitly pointed out that optek-Danulat GmbH assumes no respon-sibility for loss or damage caused due to improper use of this handbook or products described herein.

This manual is protected by copyright. However, the user may produce copies and translations if required for correct operation of the products.

On request, this manual is available in other languages as well as in digital format (Acrobat Reader 7.0 required).

Our products are being continuously improved. Technical data is subject to change without notice.

Essen, June 2012

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Table of contents

Preface

1. Using the handbook .................................................................................................1 1.1. Validity of the handbook .........................................................................................1 1.2. Pictograms and signal words .................................................................................2

2. Intended use..............................................................................................................3

3. Safety .........................................................................................................................4

4. Introduction ...............................................................................................................5 4.1. Traceability .............................................................................................................5 4.1.1. Overview.................................................................................................................5 4.1.2. Traceability of optek calibration filters ....................................................................6

5. Calibration of optek VIS and NIR sensors..............................................................7 5.1. Photometric accuracy and linearity ........................................................................7 5.1.1. Overview.................................................................................................................7 5.1.2. Calibration Device ..................................................................................................7 5.1.3. Calibration Certificate .............................................................................................9 5.2. Spectral properties .................................................................................................9 5.2.1. Overview.................................................................................................................9 5.2.2. Calibration Devices...............................................................................................10

6. Handling and Storage.............................................................................................11 6.1. Handling and Storage of optek Calibration Filters................................................11 6.2. Handling of Calibration Cuvettes..........................................................................12 6.3. Cleaning of optek Calibration Filters and Cuvettes ..............................................12

7. Calibration Procedures ..........................................................................................13 7.1. General Procedure ...............................................................................................13 7.2. Calibration with Calibration Filter..........................................................................14 7.2.1. Photometric Accuracy and Linearity.....................................................................14 7.2.1.1. Example Filter Calibration Photometric Accuracy and Linearity .......................14 7.3. Calibration with Calibration Cuvette .....................................................................16 7.3.1. Spectral Properties ...............................................................................................16 7.3.2. Example Calibration with FH03 Calibration Cuvette ............................................16

8. Linearization Curves ..............................................................................................18 8.1. General Procedure ...............................................................................................18

9. Glossary...................................................................................................................19

10. Spare parts ..............................................................................................................21

11. Appendix..................................................................................................................22 11.1. Declaration of decontamination............................................................................22 11.2. Disposal................................................................................................................22 11.3. Sample certificate for VIS-L090 Calibration Filter ................................................23 11.4. Contacts ...............................................................................................................26

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1. Using the handbook 1.1. Validity of the handbook

This handbook is only valid for optek calibration filters described in chapter 2, page 3 in combination with the inline sensors for VIS and NIR absorption indicated in chapter 4, page 5. Follow this handbook for every operation. Furthermore always observe the handbook of each measuring system to be checked. If the calibration filters are not used according to this handbook, the function of the cali-bration filters and the measuring system to be checked may be affected. To maintain reliability of the product, enhance its life cycle and avoid down times, follow the instructions given in this manual. Furthermore, please follow local accident prevention and environmental protection instructions, as well as recognized technical regulations for safe and professional operation.

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1.2. Pictograms and signal words Important information in this handbook is marked with the following pictograms:

Danger! This pictogram indicates immediate danger to life and health of persons. The

text next to the symbol gives information on how to avoid bodily injuries.

Danger! Electrical voltage.

This pictogram indicates danger due to electrical voltage.

Caution! This pictogram indicates information on how to avoid material damage.

Note! This pictogram indicates instructional or general advice.

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2. Intended use optek calibration filters and cuvettes shall only be used as a means for calibration of inline sensors for VIS and NIR absorption indicated in chapter 4, page 5. The term calibration is employed here in accordance with the definition of the International vocabulary of metrology Basic and general concepts and associated terms1 Constructional changes as well as changes to and interference with the described procedures for using the calibration filter are prohibited. Calibration with optek calibration means shall only be carried out by trained and qualified personnel. The warranty for calibration filters as well as for corresponding certificates including product traceability ex-pires in case of improper use, removal of the calibration filter from the fil-ter holder, or modification of the labelling. optek does not assume liability for loss or damage resulting from use of calibration filters. Following this handbook is part of the intended use.

1 International vocabulary of metrology- Basic and general concepts and associated terms ed.: DIN, German Institute for Standardization 2nd edition 1994

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3. Safety

Only use the calibration filter when free from defects and in accordance with the instructions provided in this handbook.

Read this handbook prior to initial commissioning. This especially applies to personnel who only occasionally carry out calibrations with calibration filters.

Observe all safety and information labels on the product and keep them in readable condition.

Inspect the product for signs of physical damage. Report any damage immediately and do not commission the product until corrective actions have been taken. Protect calibration filters and cuvettes from external influences which could affect proper function, such as dust, humidity or fingerprints.

Do not use calibration filters or cuvettes with visible damage to the filter glass or filter holder. Have such calibration means immediately checked by the manufacturer.

Spare parts must comply with technical requirements defined by optek. This is always guaranteed when using original spare parts.

This safety information is supplemented by the current national and local regulations on accident prevention and the recognized technical instruc-tions for safe and professional operation.

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4. Introduction

This handbook is a description of opteks VIS and NIR calibration filters and calibration cuvettes used to test the functionality of optek AF16-N, AF16-F, AS16-N, AS16-F and AF26 sensors. This test applies to the entire measuring chain consisting of converter, sensor and cable set. optek offers VIS and NIR calibration means for the following tests: a) Calibration of photometric accuracy and linearity (chapter 5.1 page 7

and chapter 7.2.1 page 14) b) Calibration of spectral properties (chapter 5.2 page 9 and chapter

7.3.1 page 16) The available calibration filters are test devices traceable to NIST and used to calibrate VIS and NIR sensors at user-defined and application-dependent frequencies. Determination of calibration frequencies is the users responsibility.

4.1. Traceability

4.1.1. Overview

The International vocabulary of metrology Basic and general concepts and associated terms defines traceability as the property of the result of a measurement or the value of a standard whereby it can be related to stated references, usually national or international standards, through an unbroken chain of comparisons all having stated uncertainties. These stated references can be standards developed and maintained by national or international metrological institutes, such as the Deutsche Physikalisch-Technische Bundesanstalt (the national metrology institute in Germany) or the National Institute of Standards and Technology (NIST) in the USA, or transfer standards that are linked to other working standards. The unbroken chain of comparisons is referred to as a complete, ex-plicitly described and documented series of comparisons that succes-sively link the value and uncertainty of a result of measurement with the values and uncertainties of each of the intermediate reference standards and the highest reference standard to which traceability for the result of measurement is claimed. Traceability is thus a property of a measurement and not a property of a device, calibration certificate, or laboratory. A spectrophotometer, for example, cannot be NIST-traceable. It can only be a calibrated spectrophotometer, whose measurements are traceable to NIST.

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4.1.2. Traceability of optek calibration filters

Spectrophotometers and photometers are special with respect to trace-ability since they deliver dimensionless measuring results which can thus not be traced back to SI basic units. The unbroken chain of comparisons in this case ends with measurements of a reference spectrophotometer in the NIST Advanced Chemical Sciences Laboratory(ACSL). Certification of optek calibration filters is carried out in the optek calibra-tion laboratory according to the recommendations of ISO 17025. In the center of the calibration laboratory is a spectro-photometer (Varian Cary 5000) which is subject to rigid inspection of measuring and test equip-ment in the course of which calibrations are carried out in permanently defined intervals using NIST Standard Reference Material (SRM). Just like the spectro-photometer are these SRMs also subject to a detailed determined inspection of measuring and test equipment and are recali-brated at regular intervals in a certified calibration laboratory. Details regarding used reference materials and required indications with respect to the description of traceability are given in the respective optek calibration certificate. Since the application range of NIST SRM is restricted to the UV-VIS wavelength range, measurements at wavelengths above 800nm cant be NIST traceable even if they were carried out with a spectrophotometer whose measurements are NIST traceable calibrated. Nevertheless, optek is able to provide reliable and precisely calibrated calibration filters for optek NIR photometers. For that purpose optek uses reference calibration filters as transfer standards between an optek reference NIR photometer and the spectrophotometer of the optek calibration laboratory. Prior to the calibration of a reference calibration filter with the optek reference photometer the photometer was calibrated by using the double aperture method. Details regarding used reference materials and required indications are given in the respective optek calibration certificate.

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5. Calibration of optek VIS and NIR sensors

5.1. Photometric accuracy and linearity

5.1.1. Overview

The goal of this test is to check the measuring chain, consisting of sen-sor, cable and converter, with respect to photometric accuracy. When in-troduced into the light beam, Calibration filters cause a defined light at-tenuation at individual wavelengths and wavelength ranges. Using cali-bration filters with different absorption levels tests linearity of the entire system. Insufficient photometric accuracy or linearity may be caused by the fol-lowing effects:

Non-linearity of used SI photodiodes, for instance, due to component de-fects or humidity deposits on the diode bonding

Hardware failure of the converter, e.g. defective input cards Faulty wiring of sensor and converter Damaged cable plugs or termination on sensor and / or converter Wrong product definition due to selecting the wrong measuring function Unintentional or accidental activation of calibration functions, such as Sensor Adaptation, Offset & Slope, Linearization Tables, or mA inputs affecting raw measuring values

5.1.2. Calibration Device

optek offers calibration filters VIS-L045 through VIS-L180 and NIR-L045 through NIR-L180 with nominal absorption values of 0.45 CU, 0.90 CU and 1.80 CU. These filters are almost wavelength-independent and therefore suitable for the specified wavelengths and wavelength ranges. To minimize the influence of reflections on filter surfaces, these filters are mounted in the holder in an angled position (see fig. 1), which brings the measurement values in a process photometer closer to those of a certified spectrophotometer. Since instrument specifications, such as sensor types and designs, sensor bodies, optical path length (OPL) and others, may vary and, hence, have a slight impact on the VIS-L and NIR-L filter readings, it is necessary to discriminate between initial and subsequent calibration. This allows using the calibration filter for calibrating any type of optek VIS or NIR photometer specified in chapter 4, page 5. Fig.1: FH03B filter holder with filter installed in an angled position

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a. Initial calibration During the initial calibration, the initial value of a measuring system is re-corded. The tolerance of the desired value is stated in the table 1 on page 8. If the measuring system passes initial calibration, it is very unlikely that the tested system exhibits insufficient photometric accuracy or limited linearity, caused by effects described in chapter 5.1.1, page 7. Initial values as recorded only apply to the photometer tested. They cannot be applied to any other photometer but are always required to be established for each photometer separately. After constructional changes of the photometer, the initial value must be recorded again. Constructional changes are:

Change of interference filters or detector module

Change of OPL

Retrofit or change of sensor body b. Subsequent Calibration For subsequent calibrations, the initial value as recorded and docu-mented during initial calibration serves as the desired (nominal) value of the individual photometer. For a subsequent calibration to pass, the measured value must be within a certain tolerance of the initial value. The exact tolerances for different filters and systems are listed in table 1 on page 8.

Table 1: Tolerances for initial and subsequent calibration of optek photometers with optical path lengths up to 160mm.

Initial Subsequent AF16-N AS16-N AF16-F AS16-F AF26

0.02 CU 0.03 CU 0.06 CU VIS-L045 n.a. n.a. 0.01 CU 0.015 CU 0.03 CU 0.03 CU 0.06 CU 0.06 CU VIS-L090 n.a. n.a. 0.01 CU 0.03 CU 0.03 CU 0.03 CU 0.065 CU VIS-L180 n.a. n.a. 0.01 CU

n.a 0.03 CU

0.015 CU 0.02 CU NIR-L045 0.01 CU 0.015 CU

n.a. n.a. n.a.

0.02 CU 0.03 CU NIR-L090 0.01 CU 0.015 CU

n.a. n.a. n.a.

0.03 CU 0.04 CU NIR-L180 0.01 CU 0.015 CU

n.a. n.a. n.a.

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5.1.3. Calibration Certificate VIS-L and NIR-L Filters available from optek are delivered with a calibra-tion certificate. A sample certificate is included in the appendix (chapter 11.3, page 23) of this handbook. Each of these calibration certificates contains, among other information, the following important information: Certificate number Calibration filter type with serial number

Via serial number, which is also engraved on the filter holder of the calibration filter, calibration certificate and calibration filter are cross-referenced to each other

Nominal absorption value of the filter Certified absorption value including expanded uncertainty for respec-

tive VIS and NIR wavelengths Measuring conditions, at which absorption values were recorded Spectrophotometer used for certified measurements including refer-

ence standards used for calibration of the device Application of the calibration filter to optek VIS and NIR sensors

An example is given in chapter 7.2.1.1, page 14.

5.2. Spectral properties

5.2.1. Overview

Evaluations of spectral properties are not straightforward and require a more detailed explanation. Spectrophotometers require calibration of spectral resolution and accuracy. Resolution, however, is not defined for instruments that are not adjustable in frequency (or wavelength). By the same token, spectral accuracy of photometric systems cannot be deter-mined by the location of transmission maxima. In photometers, the effective measuring wavelength is not only determined by instrument properties of the photometer but also by spectral characteristics of the compound to be analyzed. Instrument properties of a photometer are primarily defined by the installed optical filter, which is characterized by parameters, such as mean wavelength, and Full Width at Half Maximum (FWHM), and may vary within certain (tight) tolerances. If and to what extend this may effect the measurement, depends on the application itself. The best, and probably the only calibration of a process photometer with respect to concentration as the measuring quantity is the use of the product to be analyzed or monitored by the photometer. To this end, optek has introduced the FH03 calibration cuvette. Such calibrations using actual product may be carried out at defined frequencies and always prior to commissioning a VIS or NIR photometer. The advantage of doing so is the direct applicability of test results to the process meas-urement.

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5.2.2. Calibration Devices As already mentioned, the absorption spectrum of the compound to be measured also has an impact on the spectral response properties of the photometer, which is why testing of these properties must be performed with regard to the intended application. The most efficient way of testing spectral properties is, using the FH03 Calibration Cuvette (see. Fig. 2) filled with the compound to be measured. The exact procedure is described in chapter 7.3, page 16. Fig.2: Calibration Cuvette FH03

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6. Handling and Storage

6.1. Handling and Storage of optek Calibration Filters Since optek calibration filters serve as important calibration tools, they require very careful handling so that their functionality is not affected by external influences. Calibration filters should be stored in the filter storage boxes provided at ambient temperatures from 15C to 30C (59F to 86F) and a relative humidity not exceeding 70 %. Especially dust, streaks, finger marks or scratches can damage the calibration filter and require recertification. Observe the following basic conditions: Do not remove the calibration filter from the mounting. Do not change the filters orientation inside the filter holder. Do not scratch the surface. For protection, store calibration filters under exclusion of UV light in

a dust-and oil-free place. The air should be free of corrosive vapor. Storage temperature: 15C to 30C (59F to 86F) Air humidity: 0 % to 70 %

Note! Store calibration filters in dry cabinets or other appropriate cabinets so that the filters are protected against variations in temperature and humidity.

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6.2. Handling of Calibration Cuvettes Please observe the following handling instructions for opteks FH03 cali-bration cuvette: Prior to use, calibration cuvettes should be checked for cracks,

chips, and scratches and replaced if necessary. Always handle cuvettes with special care to keep inner and outer

surfaces clean and to avoid scratches. Before filling cuvettes with any solution, rinse them with distilled

water. After that, cuvettes should be partly filled with solution, shaken and turned upside down so that the solution wets the inner surface of the cuvettes. The solution should be discarded and the cuvette rinsed with water again.

Humidity and finger marks should be removed with lint-free paper or lens cleaning paper.

Do not clean cuvettes in an autoclave or in ultrasonic baths since cuvettes could be damaged.

Cuvettes should be stored in their corresponding boxes.

6.3. Cleaning of optek Calibration Filters and Cuvettes Prior to use, visually inspect calibration filters and cuvettes for dust or other soiling such as finger marks or condensation and clean them if necessary. Carefully remove any surface soiling capable of absorbing light or particles that might scatter incident radiation: Carefully remove surface particles using a soft lens brush that does

not scratch the optical surface. Remove absorbing surface soilings with a solvent that is non-

alkaline and free of surfactants (e.g. Isopropanol). Note: Calibration filters should only be cleaned when required. As a basic rule, it is recommended to avoid any soiling, especially finger marks, through proper handling of calibration filters and cuvettes.

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7. Calibration Procedures

The following chapter deals with the calibration procedures using test devices introduced in chapter 5, page 7. The described procedures only apply to optek VIS and NIR Sensors AF16-N, AF16-F, AS16-N, AS16-F and AF26. All calibration procedures are described in general. For further information, please refer to the instruction manuals of the particular converters and sensors.

7.1. General Procedure

1. Preparation The system to be calibrated must be wired and fully operational. Allow analyzer at least 30 minutes to warm up. Make sure detector assemblies are tightly screwed onto measuring cell, otherwise measurement results will be compromised.

2. Sensor Identification Record serial numbers of sensor and converter as well as activated measurement input channels of the converter.

3. Filter Identification Record serial number, filter type, date of calibration and nominal values.

4. Sensor Body and Zero Medium All procedures require a clean and empty sensor body or a sensor body completely filled with stable zero medium. It is not necessary to remove the sensor body from the pipeline. Also ensure that there is no condensation or soiling on the windows.

5. Zero Point Adjustment / Record Initial Value If possible, zero the instrument. Otherwise, record the current measuring values.

6. Record / Disable Additional Measurement Functions In case your measuring values are using calibration functions, such as Sensor Adaptation, Linearization, Damping or mA inputs, record all relevant values. If several calibration functions are being used, it is recommended creating your own Calibration Product in the C4000 converter. C4000 converters with software version C2 from December 11th, 2007, or later versions may use the Detector Monitor displaying raw measuring values. For further information on the product definition and the detector monitor, please refer to the C4000 instruction manual.

7. Remove Sealing Cover and Insert Filter Loosen the 2 screws of the sealing cover of the detector adapter

and remove sealing cover and screws. Take filter holder out of storage box and visually inspect reference

filter for dust or soiling. Clean it if necessary. Insert filter holder in the detector adapter- the two pilot pins must

be inserted in the alignment holes.

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Fig.3: Insert Calibration Filter

Note: The screws on the sealing cover are not secured against falling out. Make sure not to loose any screw.

8. Record Measuring Result

Record displayed measuring result. 9. Evaluation of Measuring Result

Take calibration functions into account that are activated, then com-pare resulting value with certified nominal value on certification.

7.2. Calibration with Calibration Filter

7.2.1. Photometric Accuracy and Linearity This test determines the accuracy and linearity of the photometer with respect to the certified nominal values. Nominal values for the photometric accuracy and linearity tests are the values given in the calibration certificate on first page. Tolerances are given in the calibration certificate on third page, chapter Instructions for use.

7.2.1.1. Example Filter Calibration Photometric Accuracy and Linearity

The following example documents a photometric accuracy test using an NIR-L090 calibration filter and sensor AF16-N. The converter settings chosen for this example include sensor adaptation and processing a mA-input. These settings must be taken into account when determining the measuring result, as shown in this example.

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Table 2: Example Initial Filter Calibration. Photometric Accuracy and Linearity

No. Description: Data:

01 Filter Type: NIR-L090

02 Filter ID: FH03B-11111-22

03 Calibration Date: 31.03.2010

04 Certified Value: 0.889CU

05 Admissible Range: 0.869 0.909CU

06 Serial Number Sensor: 12345

07 Serial Number Converter: 12346

08 Measurement Input: A

09 Sensor Adaptation ABS-CU (A): 0.9

10 Multiplication mA Input 1: yes

11 Value mA-Input: 50%

12 Measuring Result Zero Medium: 0.002

13 Measuring Result Calibration Filter: 0.401

14 Measuring Result minus Offset Zero Point (No. 12) 0.401CU-0.002=0.399

15 Compensate for Sensor Adaptation (No. 09) * (1/0.9)= 0.443

16 Compensate for mA Input (No. 10,11) * (1/0.5)=0.886

22 Calibration Value: 0.886 CU

23 Evaluation: passed For a subsequent calibration, this means: Admissible Range: 0.877 0.895

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7.3. Calibration with Calibration Cuvette

7.3.1. Spectral Properties

In chapter 5.2.1, page 9, calibration with the FH03 calibration cuvette filled with product or a specified calibration liquid has already been described as the best calibration method for photometers. This procedure tests the photometer in one single test step. When using the FH03 calibration cuvette, some additional aspects must be observed apart from the basic steps described in chapter 7.1, page 13. It is most important to note that the correlation between absorption and concentra-tion does not primarily depend on the concentration but on the reported absorp-tion. For this reason, differences in OPL between sensor body and cuvette must be corrected by a conversion factor m. Normally this procedure results in smallest deviations between cuvette and sensor body measurements. Table 3: Conversion Factor m as a Function of Sensor Body OPL

OPL [mm] 1.0 2.5 5.0 10 20 40 Conversion Factor m 0.4 1 2 4 8 16

For testing a photometer with the FH03 calibration cuvette, the product to be analyzed or any appropriate calibration liquid can be used. When choosing a calibration liquid, it is important its spectrum matches the product spectrum as much as possible. The concentration of the calibration liquid in the cuvette should roughly represent the absorption of the working point. This method also consists of initial and subsequent applications. A subsequent calibration with an FH03 calibration cuvette requires the test liquid be identical with that used for initial calibration. Since preparation of a test liquid always involves some uncertainties, and the absolute concentration of a product sam-ple can also vary within certain limits, possible differences in concentration between initial and subsequent calibration must be taken into account. For this reason, it is recommended to establish a correlation between reference meas-urement and photometric measurement during initial calibration. It is the users responsibility to choose the appropriate reference measurement, such as a spectrophotometric measurement or the absolute mass of a test liquid. In many cases, correlation was already established during the qualification process of the measuring system. In these cases, the characteristic curve for determining the actual concentration and the resulting nominal value should be used for calibration.

7.3.2. Example Calibration with FH03 Calibration Cuvette

A concentration of 100 mg/l of a substance is to be measured in a sensor body with 10 mm OPL (m=4). The weight concentration (mass) of this substance serves as a reference. The accuracy of concentration is estimated to be ap-proximately 2 %. Therefore, calibration points are chosen to be apart by 5 % increments.

Table 4: Example Calibration with FH03 Calibration Cuvette

WorkingPoint

Calibration Point

ConcentrationCuvette

Measured CU Value

95 % 380 mg/l 0.740 CU 100 % 400 mg/l 0.800 CU

100 %

105 % 420 mg/l 0.860 CU

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Thus, slope is 0.003 CU/mg/l (in the cuvette), and concentration uncertainty is 0.5 % (here 2 mg/l), corresponding to 0.006 CU tolerance range for the photometric measurement.

Fig. 4 shows the correlation between reference measurement (concentration in [mg/l]) and photometric measurement, which will be used in subsequent cali-brations for determining the photometric nominal value.

Fig. 4: Example of a Calibration Curve For a subsequent calibration, this means:

Table 5: Subsequent Calibration

Target Concentration

Actual Concentration

Absorption Out

Absorption In

Value O.K.?

400 mg/l 399 mg/l 0.796 0.006 CU 0.795 CU yes

Uncertainties including those of the sensor cannot be discussed here due to the large number of possible applications. However, it is important to note that the test will have passed if the photometric value is found to be within the un-certainties.

0.796

0.7

0.75

0.8

0.85

0.9

370 380 390 400 410 420 430c [mg/l]

CU

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8. Linearization Curves

Linearization Curves can be defined at select converters or in downstream sig-nal processing. They can serve to convert measuring result to other unit scales (mostly concentrations). Especially for non-linear correlations between concentration and absorption, use of linearization curves is recommended. When using the FH03 calibration cuvette (apart from some basic steps described in chapter 7.1, page 13), some additional aspects must be observed as well. It is important to note that the correlation between absorption and concentration depends more on reported absorption than on concentration. For example, double concentration does not necessarily mean double absorbance. For this reason, differences in OPL between sensor body and cuvette must be corrected by a conversion factor m.

8.1. General Procedure

1. Define maximum product concentration (cPmax) to be measured in the process.

2. Define the optical path length (OPL) of your sensor body. Depending on the OPL of the sensor body, conversion factors m for a calibration cuvette with 2.5 mm OPL are as follows.

Table. 6: Conversion Factor m as a Function of Sensor Body OPL

OPL [mm] 1.0 2.5 5.0 10 20 40 Conversion Factor m 0.4 1 2 4 8 16

3. Prior to establishing a linearization curve, make sure linearization tables that

may previously have been activated are disabled. In case mA input channels or sensor adaptations are active, determine to what extent they apply to the expected result and whether they affect measurement the same way as in the cuvette (such as temperature compensation).

4. It is recommended to establish a linearization curve using at least three cali-bration points, including relative concentrations of 0 % (zero medium), 50 % and 100 %. In this case concentrations required for cuvette measurement are 0.5*m* cPmax and m* cPmax. Depending on measuring range and curve shape, the user may decide to increase number of calibration points in the lineariza-tion table, if deemed necessary.

Table 7: Linearization

Product Concentration cP in the process

Product concentration cC in the cuvette

CU value measured with

cuvette

0 0

* cPmax *m* cPmax

cPmax m*cPmax

Output values in the Linearization table

Input values in the

Linearization table

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9. Glossary Table 7: Glossary

Term Explanation

Adjustment Operation of bringing a measurement system into a state of per-formance suitable for its use, such as adjusting an output value of a measuring system until its reading agrees with that of a reference standard.

AU Absorption Unit The dimensionless absorption value of log (1/T). T = % Transmission

Calibration Operation of establishing, under specified conditions, the relation-ship between values of quantities indicated by a measuring system and corresponding nominal values (calibration standards).

Conversion Factor m Factor that accounts for the difference in OPL between calibration cuvette (2,5 mm OPL) and inline sensor body in the process. Used to calculate the concentrations of calibration standards in the cu-vette, whose absorption values are equivalent to those found in the process sensor body at a different OPL.

CU Concentration Unit The dimensionless absorption value of log (1/T) measured with an optek filter photometer. T = % Transmission

Deviation of linearity Deviation of the real measurement from the theoretical linear corre-lation.

Double aperture method Method to determine the linearity of a light measurement. No refer-ence standard required here, therefore with inherent minimal meas-urement uncertainties.

Expanded uncertainty Standard uncertainty multiplied by coverage factor k to define inter-val about measurement result, within which measurements can be confidently asserted to lie. Mostly k=2, corresponding to 95% of measurements being within the interval defined.

Full Width at Half Maximum FWHM

Distance between two wavelengths of a transmission curve of an interference filter, at which transmission values are equal to 50 % of the peak maximum of this curve.

Integration time Property of a spectrophotometric measurement. Amount of time, a spectrophotometer looks at the incoming light to determine an aver-age measurement value.

Mean wavelength Center wavelength between the two wavelengths, at which trans-mission values reach 50 % of the peak maximum.

NIST National Institute of Standards and Technology, USA

NIST-traceable Measuring results tracing back to a chain of comparisons to stan-dards approved by NIST are referred to as NIST-traceable.

OD Optical Density Absorption value standardized to an optical path length (OPL) of 10 mm. OD can be calculated by dividing absorption by OPL in centi-metres.

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Optical path length (OPL) Distance that light passes through a sample.

Peak wavelength Wavelength, at which transmission curve of an interference filter reaches its maximum.

Photometric accuracy Accuracy with which a measurement of two photocurrents and the calculation of its relationship with respect to its logarithm is carried out.

Process photometer Measuring system for absorption / transmission, which measures at fix wavelength(s). Used directly in the process line.

PTB Physikalisch-Technische-Bundesanstalt, Braunschweig. National metrology institute in Germany.

Sensor adaptation Factor used to adjust measurement result of a measuring function. Function of optek C4000 converter.

Slit height Property of a spectrophotometric measurement that affects geome-try and intensity of the light beam.

Slit width Property of a spectrophotometric measurement defining spectral resolution.

Spectral accuracy Accuracy with which the set wavelength of a spectrophotometer corresponds to the target wavelength.

Spectrophotometer / Spectrometer

Apparatus measuring absorption / transmission values over a wave-length range of different wavelengths (simultaneously or succes-sively). Designed usually for laboratory use.

SRM Standard Reference Material CRM issued under the NIST trademark.

Tolerance / uncertainty Region about a measurement value, which is likely to enclose the true (correct) value.

Traceability Property of a measurement result relating the result to a stated met-rological reference through an unbroken chain of calibrations of a measuring system or comparisons, each contributing to the stated measurement uncertainty.

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10. Spare parts

Calibration filters and cuvettes VIS-L0.45 1442-0025-0223-13 VIS-L0.9 1442-0025-0223-23 VIS-L1.8 1442-0025-0223-33 NIR-L0.45 1442-0025-0213-13 NIR-L0.9 1442-0025-0213-23 NIR-L1.8 1442-0025-0213-33 FH03 calibration cuvette 1448-0102-0000-03

Recertifications Recertification VIS-L 1452-0600-1000-03 Recertification NIR-L 1452-0500-1000-03

Accessories and spare parts Case for 7 filter boxes 1450-1000-0000-00 Set stoppers for calibration cu-vette (10 pieces)

1206-0010-4840-86

O-Ring set 2.00 x 1.00 Viton (20 pieces) 1203-0020-0050-02

O-Ring set 18.77 x 1.78 Viton (4 pieces) 1203-0004-0013-02

Screw set M3 x 10 DIN7985 (10 pieces) 1206-0010-0058-01

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11. Appendix

11.1. Declaration of decontamination

For the safety of our employees and because of legal regulations we need a signed declaration of decontamination before your return can be handled. This signed declaration must be included with the shipping documents on the outside of the packaging. Any returns which were exposed to hazardous substances and were not professionally decontaminated are not accepted and will be sent back on your cost. opteks declaration of decontamination and contact information can be found on our website www.optek.com.

11.2. Disposal

Special legal regulations apply to the return and disposal of industrial waste equipment. However, manufacturer and user can contractually agree on which party is to fulfil these legal obligations. Observe current national disposal regulations. To dispose packaging material, please separate materials into the following groups:

Paper / paperboard Plastic

For disposal, disassemble the system components and separate them according to different material groups. Dispose of materials according to national and local regulations. If no agreement has been made, products may be shipped to optek for disposal.

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11.3. Sample certificate for VIS-L090 Calibration Filter

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11.4. Contacts

For further inquiry, feel free to contact us or our distributing partners at any time:

Germany optek-Danulat GmbH Emscherbruchallee 2 45356 Essen / Germany Phone: +49-(0)201-63409-0 Fax: +49-(0)201-63409-999 E-Mail: [email protected] China optek-Danulat Shanghai Co., Ltd Room 718 Building 1 No. 88 Keyuan Road Pudong Zhangjiang Shanghai, China 201203 Phone: +86 21 2898 6326 Fax: +86 21 2898 6325 E-Mail: [email protected] Singapore optek-Danulat Pte. Ltd. 25 Intl Business Park #02-09-f German Centre Singapore 609916 Phone: +65 6562 8292 Fax: +65 6562 8293 E-Mail: [email protected]

USA optek-Danulat Inc. N118 W18748 Bunsen Drive Germantown WI 53022 / USA Phone: +1 262 437 3600 Toll free call: +1 800 371 4288 Fax: +1 262 437 3699 E-Mail: [email protected]

88

718

:201203

:+86-21-28986326

:+86-21-28986325 E-Mail: [email protected]

Please visit our website for contact details of our local distributors in other countries.

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optek manual 1004 5003 02 calibration handbook vis nir us 2012-06-28

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