LaMotte 1922-EX2 User Manual

•

COD

••••••••••••••••••••••••••••••••••••••••••••••

PLUS

Colorimeter

OPERATOR’S

MANUAL

CODE 1922/1922-EX2

T ABLE OF CONTENTS

GENERAL INFORMATION

Packaging & Delivery ······································································ 5 General Precautions ········································································ 5 Safety Precautions ··········································································· 5 Limits of Liability ············································································ 5 Specifications ·················································································· 6 Contents and Accessories ································································ 7 EPA Compliance ············································································· 7 CE Compliance ················································································ 8

CHEMICAL TESTING

Water Sampling for Chemical Analysis ··········································· 9 Filtration ························································································· 10 An Introduction to Colorimetric Analysis ······································ 11 Reagent Blank ················································································· 12 Colorimeter Tubes ··········································································· 12 Selecting an Appropriate Wavelength ············································ 12 Calibration Curves ·········································································· 13 Standard Additions ········································································· 15 Sample Dilution Techniques & Volumetric Measurements ············ 16 Interferences ··················································································· 17 Stray Light Interference ·································································· 17

OPERATION OF THE COD PLUS COLORIMETER

Overview ························································································· 18 Power Source ··················································································· 18 Components ···················································································· 19 Quick Start ····················································································· 20

GENERAL OPERATING PROCEDURES

The Keypad ····················································································· 22 Sample Holders ················································································ 22 The Display & the Menus ······························································· 23 Looping Menus ················································································ 25

TESTING

Testing Menu ·················································································· 26 Sequences of Tests ··········································································· 27 General Testing Procedures ····························································· 28 Testing With the LaMotte Pre-Programmed Tests ·························· 28 Calibrating With the LaMotte Pre-Programmed Tests····················· 30 Measuring in the %T/ABS Mode ···················································· 32

COD PLUS COLORIMETER 4/03 3

T ABLE OF CONTENTS (cont.)

EDITING MENU

Edit a Sequence ·············································································· 34 Adding or Deleting Tests ································································· 35 Edit User Tests ················································································ 38 Naming the Test ·············································································· 39 Selecting the Vial and Wavelength ················································· 41 Entering a New Calibration ···························································· 42 Selecting the Numerical Format of the Result ································ 44 Selecting Units of Concentration····················································· 45 Setting the Clock ············································································· 46 Turning the Data Logger On and Off ·············································· 47 Factory Setup ··················································································· 48 Setting the Power Saver Function···················································· 48

PC LINK

Output ···························································································· 49 Computer Connection ····································································· 49

BATTERY OPERATION

Replacing the Battery······································································· 49

MAINTENANCE

Cleaning ·························································································· 50

TROUBLESHOOTING GUIDE

Error Messages ················································································· 50 Helpful Hints ··················································································· 50

SMART REAGENT SYSTEMS

······································································································· 51

COD PLUS COLORIMETER TEST INSTRUCTIONS APPENDIX

4 COD PLUS COLORIMETER 4/03

GENERAL INFORMATION

PACKAGING & DELIVERY

Experienced packaging personnel at LaMotte Company assure adequate protection against normal hazards encountered in transportation of shipments. After the product leaves the manufacturer, all responsibility for its safe delivery is assured by the transportation company. Damage claims must be filed immediately with the transportation company to receive compensation for damaged goods.

Should it be necessary to return the instrument for repair or servicing, pack instrument carefully in suitable container with adequate packing material. A return authorization number must be obtained from LaMotte Company by calling 1-800-344-3100. Attach a letter with the authorization number to the shipping carton which describes the kind of trouble experienced. This valuable information will enable the service department to make the required repairs more efficiently.

GENERAL PRECAUTIONS

Before attempting to set up or operate this instrument it is important to read the instruction manual. Failure to do so could result in personal injury or damage to the equipment.

The COD PLUS Colorimeter should not be stored or used in a wet or corrosive environment. Care should be taken to prevent water or reagent chemicals from wet colorimeter tubes from entering the colorimeter chamber.

NEVER PUT WET TUBES IN COLORIMETER.

SAFETY PRECAUTIONS

Read the labels on all LaMotte reagent containers prior to use. Some containers include precautionary notices and first aid information. Certain reagents are considered hazardous substances and are designated witha*inthe instruction manual. Material Safety Data Sheets (MSDS) are supplied for these reagents. Read the accompanying MSDS before using these reagents. Additional information for all LaMotte reagents is available in the United States from the Poison Control Center listed in the front of the phone book or by calling 1-800-222-1222. Call 1-813-248-0585 to contact the International Poison control Center. LaMotte reagents are registered with a computerized poison control information system available to all local poison control centers. Be prepared to supply the name and four-digit LaMotte code number found on the container label , listed in the test procedures, or at the top of the MSDS.

Keep equipment and reagent chemicals out of the reach of young children.

Protect Yourself and Equipment: Use Proper Analytical Techniques

LIMITS OF LIABILITY

COD PLUS COLORIMETER 6/02 5

Under no circumstances shall LaMotte Company be liable for loss of life, property, profits, or other damages incurred through the use or misuse of its products.

SPECIFICATIONS

INSTRUMENT TYPE: Colorimeter

Readout Graphical 4 line, 16 character per line LCD

Wavelengths 430nm, 620 nm

Wavelength Accuracy ±2nm

Readable Resolution Determined by reagent system

Wavelength

10 nm typical

Bandwidth

Photometric Range -2to+2A

Photometric Precision ± 0.001A

Sample Chamber Accepts 25 mm diameter flat-bottomed test tubes, 10

mm square cuvettes, 16 mm COD test tubes

Light Sources 2 LEDs

Detectors 2 silicon photodiodes with integrated interference

filters

Modes Absorbance, pre-programmed tests

Pre-Programmed Tests YES, with automatic wavelength selection

User Defined Tests Up to 10 user tests can be input

RS232 Port 8 pin mini-DIN, 9600b, 8, 1, n

Power Requirements Battery Operation: 9 volt alkaline

Line Operation: 110/220V AC;

50/60 Hz with adapter, 6V 500 mA DC

Dimensions (LxWxH) 8.5 x 16.2 x 16.7 cm, 3.4 x 6.4 x 2.6 inches

Weight 312 g, 11 oz (meter only)

Data Logger 350 test results stored for download to a PC

6 COD PLUS COLORIMETER 6/02

CONTENTS AND ACCESSORIES

CONTENTS

COD PLUS Colorimeter

Test Tubes, with Caps (4)

COD Adapter

Power Supply, 110V or 220V

COD PLUS Colorimeter Manual

ACCESSORIES

COD Reactor, 8 Vial Capacity, 110V Code 5-0069

COD Reactor, 8 Vial Capacity, 220V Code 5-0070

COD Reactor, 25 Vial Capacity, 110/220V Code 5-0094

COD Safety Shield for 8 Vial Reactor Code 5-0071

Small Field Carrying Case Code 1919-GCS150

Large Field Carrying Case Code 1919-BCS440

SMARTLink 2 Program & Interface Cable (3.5 disk) Code 1912-3

SMARTLink 2 Program & Interface Cable (CD) Code 1912-CD

EPA COMPLIANCE

The COD PLUS Colorimeter is an EPA-Accepted instrument. EP A-Accepted means that the instrument meets the requirements for instrumentation as found in test procedures that are approved for the National Primary Drinking Water Regulations (NPDWR) or National Pollutant Discharge Elimination System (NPDES) compliance monitoring programs. EPA-Accepted instruments may be used with approved test procedures without additional approval.

COD PLUS COLORIMETER 6/02 7

CE COMPLIANCE

The COD PLUS Colorimeter has earned the European CE Mark of Compliance for electromagnetic compatibility and safety.

DECLARATION OF CONFORMITY

Standards to which Conformity Declared:

Manufacturer's Name:

Manufacturer's Address:

Type of Equipment:

Model Name:

Year of Manufacture:

Testing Performed By:

Chestertown, Maryland

Place

EN61326:1998, IEC61326:1997, IEC61000-4-2:1995, IEC61000-4-3:1995 IEC61000-4-4:1995, IEC61000-4-5:1995 IEC61000-4-6:1996, IEC61000-4-11:1994, EN61000-3-2:1995, EN61000-3-3:1994-12, EN55011/CISPR11, FCCCFR47 Part 15, EN61558

LaMotte Company

802 Washington Avenue PO Box 329 Chestertown, MD 21620

Colorimeter

COD Plus

2001

Windermere 2000 Windermere Court Annapolis, MD 21401

I, the undersigned, hereby declare that the equipment specified above

conforms to the above Directive and Standards.

Signature

1/15/02

Date

8 COD PLUS COLORIMETER 6/02

Scott H. Steffen

Name

VP New Products & Quality

Position

CHEMICAL TESTING

WATER SAMPLING FOR CHEMICAL ANALYSIS

Taking Representative Samples

The underlying factor to be considered for any type of water sampling is whether or not the sample is truly representative of the source. To properly collect a representative sample:

Sample as frequently as possible.

Collect a large sample or at least enough to conduct whatever tests are necessary.

Make a composite sample for the same sampling area.

Handle the sample in such a way as to prevent deterioration or contamination before the analysis is performed.

Perform analysis for dissolved gases such as dissolved oxygen, carbon dioxide, and hydrogen sulfide immediately at the site of sampling. These factors, as well as samples for pH, cannot be stored for later examination.

Make a list of conditions or observations which may affect the sample. Other considerations for taking representative samples are dependent upon the source of the sample. Taking samples from surface waters involves different considerations than taking samples from impounded and sub-surface waters.

Sampling of Open Water Systems

Surface waters, such as those found in streams and rivers, are usually well mixed. The sample should be taken downstream from any tributary, industrial or sewage pollution source. For comparison purposes samples may be taken upstream and at the source of the pollution before mixing.

In ponds, lakes, and reservoirs with restricted flow, it is necessary to collect a number of samples in a cross section of the body of water, and where possible composite samples should be made to ensure representative samples.

To collect samples from surface waters, select a suitable plastic container with a tight fitting screw cap. Rinse the container several times with the sample to be tested, then immerse the container below the surface until it is filled to overflowing and replace the cap. If the sample is not to be tested immediately, pour a small part of the sample out and reseal. This will allow for any expansion. Any condition which might affect the sample should be listed.

Sub-surface sampling is required to obtain a vertical profile of streams, lakes, ponds, and reservoirs at specific depths. This type of sampling requires more sophisticated sampling equipment.

For dissolved oxygen studies, or for tests requiring small sample sizes, a Water Sampler (LaMotte Code 1060) will serve as a subsurface or in-depth sampler.

COD PLUS COLORIMETER 6/02 9

This weighted device is lowered to the sampling depth and allowed to rest at this depth for a few minutes. The water percolates into the sample chamber displacing the air which bubbles to the surface. When the bubbles cease to rise, the device has flushed itself approximately five times and it may be raised to the surface for examination. The inner chamber of the sampling device is lifted out and portions of the water sample are carefully dispensed for subsequent chemical analysis.

A Snap-Plunger Water Sampler (LaMotte Code 1077) is another “in-depth” sampling device which is designed to collect large samples which can be used for a multitude of tests. Basically, this collection apparatus is a hollow cylinder with a spring loaded plunger attached to each end. The device is cocked above the surface of the water and lowered to the desired depth. A weighted messenger is sent down the calibrated line to trip the closing mechanism and the plungers seal the sample from mixing with intermediate layers as it is brought to the surface. A special drain outlet is provided to draw off samples for chemical analysis.

Sampling of Closed System

To obtain representative samples from confined water systems, such as pipe lines, tanks, vats, filters, water softeners, evaporators and condensers, different considerations are required because of chemical changes which occur between the inlet and outlet water. One must have a basic understanding of the type of chemical changes which occur for the type of equipment used. Also, consideration should be given to the rate of passage and retaining time for the process water.

Temperature changes play an important part in deciding exactly what test should be performed. Process water should be allowed to come to room temperature, 20–25°C, before conducting any tests.

When drawing off samples from an outlet pipe such as a tap, allow sample to run for several minutes, rinsing the container several times before taking the final sample. Avoid splashing and introduction of any contaminating material.

FILTRATION

When testing natural waters that contain significant turbidity due to suspended solids and algae, filtration is an option. Reagent systems, whether EPA, Standard Methods, LaMotte or any others, will generally only determine dissolved constituents. Both EPA and Standard Methods suggest filtration through a 0.45 micron filter membrane, to remove turbidity, for the determination of dissolved constituents.** T o test for total constituents, organically bound and suspended or colloidal materials, a rigorous high temperature acid digestion is necessary.

**LaMotte offers a filtering apparatus: syringe assembly (Code 1050) and membrane filters, 0.45 micron, (Code 1103).

10 COD PLUS COLORIMETER 6/02

AN INTRODUCTION TO COLORIMETRIC ANALYSIS

Most test substances in water are colorless and undetectable to the human eye. To test for their presence we must find a way to “see” them. The COD PLUS Colorimeter can be used to measure a test substance that is itself yellow or green to blue, or can be reacted to produce these colors. In fact a simple definition of colorimetry is “the measurement of color” and a colorimetric method is “any technique used to evaluate an unknown color in reference to known colors”. In a colorimetric chemical test the intensity of the color from the reaction must be proportional to the concentration of the substance being tested. Some reactions have limitations or variances inherent to them that may give misleading results. Many such interferences are discussed with each particular test instruction. In the most basic colorimetric method the reacted test sample is visually compared to a known color standard. However, accurate and reproducible results are limited by the eyesight of the analyst, inconsistencies in the light sources, and the fading of color standards.

To avoid these sources of error, a colorimeter can be used to photoelectrically measure the amount of colored light absorbed by a colored sample in reference to a colorless sample (blank).

White light is made up of many different colors or wavelengths of light. A colored sample typically absorbs only one color or one band of wavelengths from the white light. Only a small difference would be measured between white light before it passes through a colored sample versus after it passes through a colored sample. The reason for this is that the one color absorbed by the sample is only a small portion of the total amount of light passing through the sample. However, if we could select only that one color or band of wavelengths of light to which the test sample is most sensitive, we would see a large difference between the light before it passes through the sample and after it passes through the sample.

The COD PLUS Colorimeter passes one of two colored light beams through one of two optical filters which transmits only one particular color or band of wavelengths of light to the photodectector where it is measured. The difference in the amount of colored light transmitted by a colored sample is a measurement of the amount of colored light absorbed by the sample. In most colorimetric tests the amount of colored light absorbed is directly proportional to the concentration of the test factor producing the color and the path length through the sample. However, for some tests the amount of colored light absorbed is inversely proportional to the concentration.

The choice of the correct wavelength for testing is important. It is interesting to note that the wavelength that gives the most sensitivity (lower detection limit) for a test factor is the complementary color of the test sample. For example the Nitrate-Nitrogen test produces a pink color proportional to the nitrate concentration in the sample (the greater the nitrate concentration, the darker the pink color). A wavelength in the green region should be selected to analyze this sample since a pinkish-red solution absorbs mostly green light.

COD PLUS COLORIMETER 6/02 11

REAGENT BLANK

Some tests will provide greater accuracy if a reagent blank is determined to compensate for any color or turbidity resulting from the reagents themselves. A reagent blank is performed by running the test procedure on 10 mL of demineralized water. Use sample water to SCAN BLANK. Insert the reagent blank in the colorimeter chamber and select SCAN SAMPLE. Note result of reagent blank. Perform the tests on the sample water as described. Subtract results of reagent blank from all subsequent test results. NOTE: Some tests require a reagent blank to be used to SCAN BLANK.

COLORIMETER TUBES

Colorimeter tubes which have been scratched through excessive use should be discarded and replaced with new ones. Dirty tubes should be cleaned on both the inside and outside. Fingerprints on the exterior of the tubes can cause excessive light scattering and result in errors. Handle the tubes carefully, making sure the bottom half of the tube is not handled.

LaMotte Company makes every effort to provide high quality colorimeter tubes. However, wall thicknesses and diameter of tubes may still vary slightly. This may lead to slight variations in results (e.g. if a tube is turned while in the sample chamber, the reading will likely change slightly). To eliminate this error put the tubes into the sample chamber with the same orientation every time.

The tubes that are included with the colorimeter have an index mark to facilitate this. If possible, use the same tube to SCAN BLANK and SCAN SAMPLE.

SELECTING AN APPROPRIATE WAVELENGTH

The most appropriate wavelength to use when creating a calibration curve is usually the one which gives the greatest change from the lowest reacted standard concentration to the highest reacted standard concentration. However, the absorbance of the highest reacted standard concentration should never be greater than 2.0 absorbance units. Scan the lowest and highest reacted standards at different wavelengths using the absorbance mode to find the wavelength which gives the greatest change in absorbance without exceeding

2.0 absorbance units. Use this wavelength to create a calibration curve.

12 COD PLUS COLORIMETER 6/02

Below is a list of suggested wavelengths for the color of the reacted samples. Use these as a starting point.

Sample

Color

Yellow 430

Pink 520

Red 570

Green and Blue 620

Wavelength

Range

NOTE: Available wavelengths in the COD PLUS are 430 nm and 620 nm only.

CALIBRATION CURVES

The COD PLUS Colorimeter contains precalibrated tests for the LaMotte reagent systems (p. 49). The first step in using a non-LaMotte reagent system with your COD PLUS Colorimeter is to create a calibration curve for the reagent system. To create a calibration curve, prepare standard solutions of the test factor and use the reagent system to test the standard solutions with the COD PLUS Colorimeter. Select a wavelength for the test as described above.

Plot the results (in ABS or %Transmittance) versus concentration to create a calibration curve. The calibration curve may then be used to identify the concentration of an unknown sample by testing the unknown, reading Absorbance or %T, and finding the corresponding concentration from the curve. The linear range of the reagent system can be determined and this information can be used to input a User Test into the COD PLUS Colorimeter (see EDIT USER TESTS, p. 36).

PROCEDURE

1. Prepare 5 or 6 standard solutions of the factor being tested. The

concentration of these standards should be evenly distributed throughout the range of the reagent system, and should include a 0 ppm standard (distilled water). For instance, the solutions could measure 0, 10%, 30%, 50%, 70%, and 90% of the system’s maximum range.

2. Turn on the COD PLUS Colorimeter . Select the appropriate wavelength

from the absorbance mode. Be sure to select the appropriate wavelength for the color produced by the reagent system.

3. Use the unreacted 0 ppm standard to standardize the colorimeter by using it

to scan blank.

4. Following the individual reagent system instructions, react each standard

solution beginning with 0 ppm. Continue with standards in increasing concentration. Record the reading and the standard solution concentration on a chart. Readings can be recorded as percent transmittance (%T) or absorbance (A).

COD PLUS COLORIMETER 6/02 13

5. Plot results on graph paper or computer using any available plotting

program. If results are as %T versus concentration, semilog graph paper must be used. Plot the standard solution concentrations on the horizontal, linear axis, and the %T on the vertical, logarithmic axis. If results are as absorbance versus standard solution concentration, simple linear graph paper can be used. Plot the standard solution concentration on the horizontal axis, and the absorbance on the vertical axis.

6. After plotting the results, draw a line, or curve, of best fit through the

plotted points. The best fit may not connect the points. There should be approximately an equal number of points above the curve as below the curve. Some reagent systems will produce a straight line, while others produce a curve. Many computer spreadsheet programs can produce the curve of best fit by regression analysis of the standard solution data.

NOTE: Only reagent systems which produce a straight line can be used for a User Test.

A sample of each type of graph appears below:

CALIBRATION CURVE

Absorbance vs. Concentration

2.0

1.8

1.6

1.4

1.2

1.0

0.8

0.6

Absorbance

0.4

0.2

0.0 123456

Concentration in ppm

CALIBRATION CURVE

%T vs. Concentration

100

%T Transmission

89107

123456

Concentration in ppm

891070

14 COD PLUS COLORIMETER 6/02

PREPARING DILUTE STANDARD SOLUTIONS

Standard solutions should be prepared to create a calibration curve. Standard solutions can be prepared by diluting a known concentrated standard by specified amounts. A chart or computer spreadsheet can be created to determine the proper dilutions. Use volumetric flasks and volumetric pipets for all dilutions.

1. In Column A – Record the maximum concentration of test as determined

by the range and path length.

2. In Column B – Record the percent of the maximum concentration the

standard solution will be.

3. In Column C – Calculate the final concentration of the diluted standard

solutions by multiplying the maximum concentration (In Column A) by the % of maximum concentration divided by 100. (C=Ax

100

4. In Column D – Record the final volume of the diluted sample (i.e. volume

of volumetric flask).

5. In Column E – Record the concentration of the original standard.

6. In Column F – Calculate the milliliters of original standard required

(C x

= F).

A sample chart appears below:

A B C=Ax

I00

D E F=Cx

Final

Maximum

concentration

of test

%of

Maximum

concentration

of Diluted

Standard

Volume of

Standard

Concentration

of Original

Standard

Standard Required

10.0 ppm 90 9.0 ppm 100 mL 1000 ppm 0.90 mL

10.0 ppm 70 7.0 ppm 100 mL 1000 ppm 0.70 mL

10.0 ppm 50 5.0 ppm 100 mL 1000 ppm 0.50 mL

10.0 ppm 30 3.0 ppm 100 mL 1000 ppm 0.30 mL

10.0 ppm 10 1.0 ppm 100 mL 1000 ppm 0.10 mL

10.0 ppm 0 0 ppm 100 mL 1000 ppm 0 mL

mL of

Original

STANDARD ADDITIONS

A common method to check the accuracy and precision of a test is by standard additions. In this method a sample is tested to determine the concentration of the test substance. A second sample is then “spiked” by the addition of a known quantity of the test substance. The second sample is then tested. The determined concentration of the spiked sample should equal the concentration of the first plus the amount added with the spike. The procedure can be repeated with larger and larger “spikes.” If the determined concentrations do not equal the concentration of the sample plus that added with the “spike”, then an interference may exist.

COD PLUS COLORIMETER 6/02 15

For example, a 10.0 mL water sample was determined to contain 0.3 ppm iron. To a second 10.0 mL sample, 0.1 mL of 50 ppm iron standard was added. The concentration of iron due to the “spike” was (0.10 mL x 50 ppm)/10.0 mL =

0.50 ppm. The concentration of iron determined in the spiked sample should be 0.3 + 0.5 = 0.8 ppm iron. (Note: any error due to the increased volume from the “spike” is negligible).

LaMotte offers a line of calibration standards which can be used to generate calibration curves and perform standard additions.

SAMPLE DILUTION TECHNIQUES

& VOLUMETRIC MEASUREMENTS

If a test result using the COD PLUS Colorimeter gives an OVERRANGE message then the sample concentration could be over range or under range. If it is over range, the sample must be diluted. Then the test should be repeated on the diluted sample to obtain a reading which is in the concentration range for the test. (Note: This is not true for colorimetric determination of pH.)

Example:

Measure 5 mL of the water sample into a graduated cylinder. Add demineralized water until the cylinder is filled to the 10 mL line. The sample has been diluted by one-half, and the dilution factor is therefore 2. Perform the test procedure, then multiply the resulting concentration by 2 to obtain the test result.

The following table gives quick reference guidelines on dilutions of various proportions. All dilutions are based on a 10 mL volume, so several dilutions will require small volumes of the water sample. Graduated pipets should be used for all dilutions.

Size of Sample

10 mL 0 mL 1

5mL 5mL 2

2.5 mL 7.5 mL 4 1 mL 9 mL 10

0.5 mL 9.5 mL 20

Deionized W ater to Bring

Volume to 10 mL Multiplication Factor

If the above glassware is not available, dilutions can be made with the colorimeter tube. Fill the tube to the 10 mL line with the sample then transfer it to another container. Add 10 mL volumes of demineralized water to the container and mix. T ransfer back 10 mL of the diluted sample to the tube and follow the test procedure. Continue diluting and testing until a reading, which is in the concentration range for the test, is obtained. Be sure to multiply the concentration found by the dilution factor (the number of total 10 mL volumes used).

Example:

10 mL of sample is diluted with three 10 mL volumes of demineralized water; the dilution factor is four.

16 COD PLUS COLORIMETER 6/02

INTERFERENCES

LaMotte reagent systems are designed to minimize most common interferences. Each individual test instruction discusses interferences unique to that test. Be aware of possible interferences in the water being tested.

The reagent systems also contain buffers to adjust the water sample to the ideal pH for the reaction. It is possible that the buffer capacity of the water sample may exceed the buffer capacity of the reagent system and the ideal pH will not be obtained. If this is suspected, measure the pH of a reacted distilled water reagent blank using a pH meter. This is the ideal pH for the test. Measure the pH of a reacted water sample using the pH meter. If the pH is significantly different from the ideal value, the pH of the sample should be adjusted before testing.

Interferences due to high concentration of the substance being tested, can be overcome by sample dilution (p. 16).

STRAY LIGHT INTERFERENCE

When scanning samples in 16 mm tubes, such as COD, the sample chamber lid can not be closed. The COD adapter minimizes stray light. To further reduce stray light interference, do not scan sample in direct sunlight.

COD PLUS COLORIMETER 6/02 17

OPERA TION OF THE COD PLUS COLORIMETER

OVERVIEW

The COD PLUS Colorimeter is a portable, microprocessor controlled, direct reading colorimeter. It has a graphical 4 line, 16 character liquid crystal display for graphical, alphabetical and numerical messages. The operation is controlled with the keypad through menu driven software in response to selections shown on the display.

The test library consists of 29 LaMotte tests and 10 “User Tests”. The LaMotte tests are precalibrated for LaMotte reagent systems. The colorimeter displays the results of these tests directly in units of concentration. The 10 “User Tests” may be used to enter additional calibrations. All of these tests may be arranged in any of 3 sequences. These sequences can be modified a limitless number of times to meet changing testing needs.

The optics feature 2 different colored LEDs. Each LED has a corresponding silicon photodiode with an integrated interference filter. The interference filters select a narrow band of light from the corresponding LED for the colorimetric measurements. The microprocessor automatically selects the correct LED/photodiode combination for a test.

A RS-232 serial port on the back of the colorimeter, and optional software, allows the COD PLUS to be interfaced with an IBM compatible personal computer for real time data acquisition and data storage. This port also allows an interface with a RS-232 serial printer.

Due to its portability, alternate power sources, and rugged construction, the COD PLUS Colorimeter is ideal for lab and field use.

POWER SOURCE

The COD PLUS Colorimeter uses a 6V 500 mA AC adapter. Please refer to the Parts List for the code number for the correct adapter.

USE OF ANY AC ADAPTER OTHER THAN THE ONE SPECIFIED FOR USE WITH THE COD PLUS COLORIMETER MAY DAMAGE THE METER AND WILL VOID THE WARRANTY.

To use the adapter, slide the connector pin from the AC adapter into the small hole on the left side of the meter. Plug the AC adapter into an appropriate wall socket or power source.

18 COD PLUS COLORIMETER 6/02

COMPONENTS

Figure 1 shows a diagram of the COD PLUS Colorimeter and its components.

Top View

COD PLUS

••••••••••••••••••

ENTER

OFF EXIT

Lid

Side Views

Bottom View

Serial Number

Battery Compartment

Rs232 Serial Port

AC Adapter Socket

Figure 1

COD PLUS COLORIMETER 6/02 19

QUICK START

Some quick instructions to get into testing.

1. Press ON to turn on the COD PLUS. The LaMotte logo screen will appear for about 2 seconds and then the Start screen appears. Press Q/ENTER to start testing.

2. The Main Menu will appear. Press Q/ENTER to select TESTING MENU.

3. Press Q/ENTER to select All Tests.

4. Press t or s to move the * to the desired test.

5. Press Q/ENTER to select test.

VER 1.0

COD PLUS

* Start

MAIN MENU

* Testing Menu

Editing Menu

PC Link

TESTING MENU

* All Tests

Sequence 1

Sequence 2

ALL TESTS

* 001 COD LR

002 COD SR

003 COD HR

ALL TESTS

* 002 COD SR

003 COD HR

004 Ammonia-N LF

6. Insert blank, press Q/ENTER to scan blank.

7. The screen will display Blank Done for about 1 second.

20 COD PLUS COLORIMETER 6/02

002 COD SR

* Scan Blank

002 COD SR

Blank Done

* Scan Blank

8. Insert the reacted sample. Press Q/ENTER to scan sample. The COD PLUS will scan the sample and display the concentration.

002 COD SR

* Scan Sample

9. After recording test result, scroll with t or s and make another selection with Q/ENTER. Press EXIT to escape to previous menus.

002 COD SR

722 mgL

* Scan Sample

COD PLUS COLORIMETER 6/02 21

GENERAL OPERATING PROCEDURES

The operation of the COD PLUS Colorimeter is controlled by a microprocessor. The microprocessor is programmed with menu driven software. A menu is a list of choices. This allows a selection of various tasks for the colorimeter to perform, such as, scan blank, scan sample, and edit test sequences. The keypad is used to make menu selections which are viewed in the display. There are three selections accessible from the MAIN MENU: Testing Menu, Editing Menu and PC Link.

THE KEYPAD

The keypad has 6 buttons which are used to perform specific tasks.

t This button will cause the display to scroll down through a list of

s This button will cause the display to scroll up in a list of menu

ENTER

EXIT

OFF

SAMPLE HOLDERS

The sample chamber is designed for 25 mm round tubes, and a sample holder for 16 mm COD tubes is included. A 1 cm square UDV cuvette sample holder is available for the COD PLUS Colorimeter.

Position the COD adapter in the SMART 2 chamber so that the grooves in the adapter are aligned with the ridges located at the rear of the chamber. The adapter should be inserted with the small hole, containing the ball plunger, at the top. The ball plunger can be adjusted with a small screwdriver to control the tightness of the fit of the tube in the adapter.

This button is used to turn the colorimeter on.

menu choices. It will move through a list viewed in the display . It will auto scroll when held down.

choices. It will move through a list viewed in the display. It will auto scroll when held down.

This button is used to select the menu choice adjacent to the “*”in a menu viewed in the display.

This button is an exit or escape button. When pressed, the display will exit from the current menu and go to the previous menu.

This button turns the colorimeter off.

22 COD PLUS COLORIMETER 8/02

THE DISPLAY & THE MENUS

The display allows menu selections to be viewed and chosen. These choices instruct the colorimeter to perform specific tasks. The menus are viewed in the display using two general formats which are followed from one menu to the next. Each menu is a list of choices or selections.

There are four lines in the display. The top line in each menu is a title or pertinent instruction. The top line does not change unless a new menu is selected. The second and third lines are used in two ways. One way is to display menu choices. The second way takes advantage of the graphical capabilities of the display. Both lines are used to display important messages, such as test results, in a large, easy to read format. The fourth line is used for menu choices.

DISPLAY

TESTING MENU

* FIRST CHOICE

SECOND CHOICE ANOTHER AND ANOTHER AND SO ON

TITLE or INSTRUCTION

MENU CHOICE WINDOW

Think of the menu choices as a vertical list in the display which moves up or down each time an arrow button is pressed. This list or menu is viewed through a window, the menu choice window, in the display. The menu choice window is the lower 2 or 3 lines of the display. Pushing the arrow buttons brings another portion of the menu into menu choice window. This is referred to as scrolling through the menu.

TESTING MENU

* FIRST CHOICE SECOND CHOICE ANOTHER

SECOND CHOICE * ANOTHER AND ANOTHER

ANOTHER AND ANOTHER * AND SO ON

AND ANOTHER AND SO ON LAST CHOICE

AND SO ON LAST CHOICE

LAST CHOICE

TESTING MENU

An asterisk, “*”, will start in the far left position of the top line in the menu choice window. As the menu is scrolled through, different choices appear next to the “*”. The “*” in the display corresponds with the Q/ENTER button. Pushing the Q/ENTER button selects the menu choice which is adjacent to the “*” in the menu choice window.

COD PLUS COLORIMETER 6/02 23

The second general format of the display takes advantage of the graphics capabilities of the display. The top line of the display is still a title line. The middle two lines of the display are used to display important messages, results or graphics in a large, easy to read format. The menus work in the same way as described previously but only one line of the menu is visible at the bottom of the display.

TESTING MENU

Result or Message Result or Message Result or Message

* ANOTHER * AND ANOTHER * AND SO ON

AND ANOTHER AND SO ON LAST CHOICE

AND SO ON LAST CHOICE

LAST CHOICE

As described previously, the EXIT button allows an exit or escape from the current menu and a return to the previous menu. This allows a rapid exit from an inner menu to the main menu by repeatedly pushing the Pushing

OFF at any time will turn the colorimeter off.

EXIT button.

24 COD PLUS COLORIMETER 6/02

LOOPING MENUS

Long menus, such as All Tests, incorporate a looping feature which allow the user to quickly reach the last choice in the menu from the first choice. In a looping menu the last choices in the menu are above the first choice and scrolling upward moves through the menu in reverse order. Scrolling downward moves through the menu from first choice to last but the menu starts over following the last choice. So all menu choices can be reached by scrolling in either direction. The diagrams below demonstrate a looping menu.

AND SO ON AND ANOTHER ANOTHER

: : : AND SO ON AND ANOTHER

: : : : : : AND SON ON

THIRD TO LAST : : : : : :

SECOND TO LAST THIRD TO LAST : : :

LAST CHOICE SECOND TO LAST THIRD TO LAST

TESTING MENU

* FIRST CHOICE * LAST CHOICE * SECOND TO LAST

SECOND CHOICE FIRST CHOICE LAST CHOICE

ANOTHER SECOND CHOICE FIRST CHOICE

AND ANOTHER ANOTHER SECOND CHOICE

AND SO ON AND ANOTHER ANOTHER

: : : AND SO ON AND ANOTHER

: : : : : : AND SO ON

LAST CHOICE : : : : : :

TESTING MENU

COD PLUS COLORIMETER 6/02 25

TESTING

TESTING MENU

The Testing Menu is used to run all LaMotte pre-programmed tests, USER TESTS and Absorbance test at two wavelengths. Testing from any of three

sequences can also be done.

1. Press the ON button to turn on the COD PLUS Colorimeter. The LaMotte logo will appear for about 2 seconds and the the Start screen appears. Press the Q/ENTER button to begin testing.

2. The MAIN MENU will appear. Press the Q/ENTER button to select Testing Menu.

3. Scroll with the t or s buttons and make a selection with the Q/ENTER button. All Tests has all the available tests. The three sequences have selected tests and

Absorbance has %T/ABS tests.

VER 1.0

COD PLUS

* Start

MAIN MENU

* Testing Menu

Editing Menu

PC Link

TESTING MENU

* All Tests

Sequence 1

Sequence 2

Sequence 3

Absorbance

26 COD PLUS COLORIMETER 6/02

SEQUENCES OF TESTS

SEQUENCE 1, SEQUENCE 2, and SEQUENCE 3 are alterable sequences. They may be edited using the Editing Menu. Any of the LaMotte pre-programmed tests or User T ests may be placed in these sequences in whatever testing order that is preferred. Some examples of typical sequences are given below.

SEQUENCE 1 SEQUENCE 2 SEQUENCE 3

* 004 Ammonia-N LF * 008 Cobalt * 001 COD LR

005 Ammonia-N LS 010 Cu Cuprizone 002 COD SR

006 Ammonia-N H 011 Cu - DDC 003 COD HR

007 Boron 015 Hydrazine

001 COD LR 016 Moly HR

002 COD SR 017 Nickel

003 COD HR 018 Ozone-LR

009 Color 021 Phosphate-H

013 DO 022 Potassium

014 Fluoride 023 Silica-Lo

018 Ozone-LR 024 Silica-Hi

020 Phosphate-L 027 Tannin

025 Sulfate-HR 029 Zinc-LR

026 Sulfide-LR

028 Turbidity

These alterable sequences allow a series of tests to be setup that are run frequently. The order of the individual tests in the sequence is determined by the user. After running a test, use the t button to scroll to the next test and press the Q/ENTER button to select the next test in the sequence. Continue this pattern until the entire sequence has been completed.

All Tests is a fixed sequence containing the LaMotte pre-programmed tests, User Tests, and Absorbance tests.

Modification of the alterable sequences is accomplished through the Editing Menu. This menu is explained in greater detail in EDITING MENU (p. 32).

Pressing the EXIT button while in a sequence menu will escape back to the

Testing Menu.

Pressing the OFF button at any time will turn the colorimeter off.

COD PLUS COLORIMETER 6/02 27

GENERAL TESTING PROCEDURES

The following are some step by step examples of how to run tests from the Testing Menu. These test procedures are designed to be used with LaMotte SMART Reagent Systems.

TESTING WITH THE LaMOTTE

PRE-PROGRAMMED TESTS

Press ON to turn on the COD PLUS Colorimeter. The LaMotte logo will appear for about 2 seconds and then the Start screen appears. Press the Q/ENTER button to start testing.

The MAIN MENU will appear. Press the Q/ENTER button to select Testing Menu.

Press the Q/ENTER button to select All Tests.

Press the t button to move to the 001 COD LR to

VER 1.0

COD PLUS

* Start

MAIN MENU

* Testing Menu

Editing Menu

PC Link

TESTING MENU

* All Tests

Sequence 1

Sequence 2

ALL TESTS

* 001 COD LR

002 COD SR

003 COD HR

Press the Q/ENTER button to select 001 COD LR.

28 COD PLUS COLORIMETER 6/02

ALL TESTS

* 001 COD LR

002 COD SR

003 COD HR

The COD PLUS Colorimeter is ready to scan at the correct wavelength. Place the blank in the sample chamber, close the lid and press the Q/ENTER button to scan blank.

NOTE: Do not keep the button depressed.

001 COD LR

* Scan Blank

The screen will display Blank Done for about 1 second. Scan Sample will be positioned next to *.

Place the reacted sample in the chamber, close the lid and press the Q/ENTER button to scan sample. The colorimeter will scan the sample and the results screen will appear.

Record test result. To repeat the test, press the Q/ENTER button to scan the sample again. The last blank scanned is used to zero the colorimeter for repeated scans. A different blank can be used by pressing the s button to scroll back to Scan Blank and then scanning another blank. Scroll with the t or s buttons and make another selection with the Q/ENTER button. The %T or Absorbance of the last test can be viewed by choosing %T/Abs. Press the EXIT button to escape to previous menus.

NOTE: The menus loop in this screen so either the s or t buttons will lead to the menu selection needed.

001 COD LR

Blank Done

* Scan Blank

001 COD LR

* Scan Sample

001 COD LR

100 mgL

* Scan Blank

Next Test

Previous Test

%/Abs

Scan Blank

COD PLUS COLORIMETER 6/02 29

CALIBRATING LaMOTTE PRE-PROGRAMMED TESTS

The LaMotte Pre-Programmed T ests have been pre-calibrated. Recalibration of the pre-programmed tests by the user is not possible. However, a procedure to standardize the calibration can be performed to obtain the most accurate readings or to meet regulatory requirements.

The LaMotte Pre-Programmed tests are standardized with one standard solution. To standardize over the full range of the test, the concentration of the standard should be chosen from the high end of the range. Alternatively , if samples do not cover the full range of the test, a standard should be chosen that is close to the concentration of the samples.

The standardization procedure should be followed as often as required by regulations and laws for compliance monitoring.

In the example below the Aluminum calibration will be standardized.

Prepare a standard solution to be tested. Use 0.10 ppm aluminum.

Use the s or t button to scroll to 002 Aluminum. Follow instructions in the COD PLUS Manual for testing the aluminum standard. Scan the blank.

The screen will display Blank Done for about 1 second. Scan Sample will be positioned next to *.

Place the reacted sample in the chamber, close the lid and press Q/ENTER to scan sample. The result will be displayed.

The displayed result can now be standardized. Use the s or t buttons to scroll to Calibrate. Press Q/ENTER to select.

002 Aluminum

* Scan Blank

002 Aluminum

Blank Done

* Scan Sample

002 Aluminum

* Scan Sample

002 Aluminum

0.09 ppm

* Scan Sample

Next Test

Previous Test

%T/Abs

Calibrate

Scan Blank

30 COD PLUS COLORIMETER 4/03

+ 103 hidden pages