Hach-Lange 2100ANIS User Manual

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DOC022.52.80206

2100AN IS

08/2012, Edition 2

User Manual

Table of Contents

Specifications..................................................................................................................................................................................5

General information.....................................................................................................................................................................6

Safety information..............................................................................................................................................................................6

Use of hazard information..................................................................................................................................................................6

Precautionary labels..........................................................................................................................................................................7

Certification........................................................................................................................................................................................7

Product overview...............................................................................................................................................................................7

Product components..........................................................................................................................................................................8

Installation.........................................................................................................................................................................................9

Put paper in the printer......................................................................................................................................................................9

User interface................................................................................................................................................................................10

Startup...............................................................................................................................................................................................12

Turn the instrument on.....................................................................................................................................................................12

Turn the keypad sound off (optional)...............................................................................................................................................12

Set the date and time.......................................................................................................................................................................12

Show the current time (optional)......................................................................................................................................................12

Standard operation....................................................................................................................................................................12

Calibrate the turbidimeter with StablCal® Standards.......................................................................................................................12

Prepare the StablCal standards................................................................................................................................................13

Calibration notes.......................................................................................................................................................................13

StablCal calibration procedure..................................................................................................................................................14

StablCal standards storage......................................................................................................................................................15

Using Gelex secondary standards...................................................................................................................................................15

Gelex notes...............................................................................................................................................................................15

Measure the Gelex stray light standard....................................................................................................................................15

Measure the Gelex secondary turbidity standards...................................................................................................................16

Calibration verification..............................................................................................................................................................17

Optical system check................................................................................................................................................................17

Prepare a sample cell......................................................................................................................................................................17

Table of Contents

Clean the sample cell...............................................................................................................................................................18

Indexing a single sample cell....................................................................................................................................................19

Matching sample cells..............................................................................................................................................................21

Prepare dilution water...............................................................................................................................................................23

Prepare the sample..........................................................................................................................................................................23

Prepare a representative sample..............................................................................................................................................23

Remove air bubbles from the sample.......................................................................................................................................23

Apply a vacuum.................................................................................................................................................................23

Use an ultrasonic bath.......................................................................................................................................................23

Apply heat..........................................................................................................................................................................24

Prevent condensation on a sample cell....................................................................................................................................24

Measure over-range samples...................................................................................................................................................24

Sample dilution..................................................................................................................................................................24

Turbidity measurement....................................................................................................................................................................25

Measurement notes..................................................................................................................................................................25

Turbidity measurement procedure............................................................................................................................................26

Absorbance and transmittance measurement.................................................................................................................................27

Measurement notes..................................................................................................................................................................27

Absorbance and transmittance measurement procedure.........................................................................................................27

Measurement techniques.................................................................................................................................................................28

Manual or automatic ranging....................................................................................................................................................28

Signal averaging on or off.........................................................................................................................................................28

Ratio on or off...........................................................................................................................................................................29

Using the air purge system.......................................................................................................................................................29

Using a flow cell........................................................................................................................................................................30

Install a flow cell................................................................................................................................................................30

Clean a flow cell assembly................................................................................................................................................30

Flow cell maintenance.......................................................................................................................................................31

Flow cell operation.............................................................................................................................................................31

Flow cell storage................................................................................................................................................................31

Using a manual flow cell....................................................................................................................................................31

Using an automated flow cell.............................................................................................................................................31

Measurement notes...........................................................................................................................................................32

Table of Contents

Static or dynamic measurement procedure.......................................................................................................................33

Use a cell adapter.....................................................................................................................................................................34

Install a cell adapter...........................................................................................................................................................35

Remove a cell adapter.......................................................................................................................................................35

Connect to a printer or computer.....................................................................................................................................................35

Configure the printer output.............................................................................................................................................................35

Configure the RS232 connection.....................................................................................................................................................36

Computer (RS232) commands........................................................................................................................................................36

Connect to a data recorder..............................................................................................................................................................36

Configure the data recorder output..................................................................................................................................................37

Advanced operation..................................................................................................................................................................37

Calibrate the turbidimeter with formazin standards..........................................................................................................................37

Prepare formazin standards.....................................................................................................................................................37

Calibration notes.......................................................................................................................................................................38

Formazin calibration procedure................................................................................................................................................39

Making 4000-NTU formazin stock solution...............................................................................................................................40

Calibrate the turbidimeter with user-selected formazin standards...................................................................................................40

Prepare formazin standards – user selected............................................................................................................................41

Change the calibration points...................................................................................................................................................41

Special research applications..........................................................................................................................................................41

Application specific methods............................................................................................................................................................41

Application specific calibration.........................................................................................................................................................41

Initial ASC entry........................................................................................................................................................................42

Program new ASC data............................................................................................................................................................42

Set the units available on the display...............................................................................................................................................42

Maintenance...................................................................................................................................................................................42

Clean the instrument........................................................................................................................................................................42

Replace the LED light source..........................................................................................................................................................42

Replace a fuse.................................................................................................................................................................................43

Troubleshooting..........................................................................................................................................................................43

Error codes .....................................................................................................................................................................................43

Table of Contents

Diagnostic codes..............................................................................................................................................................................44

Delete calibration data.....................................................................................................................................................................44

Flashing 9s.......................................................................................................................................................................................45

Flashing 0s.......................................................................................................................................................................................45

Replacement parts and accessories...............................................................................................................................45

Specifications

Specifications are subject to change without notice.

Specification Details

Measurement method Nephelometric

Regulatory Meets ISO 7027, DIN EN 27027, DIN 38404 and NFT

9033

ASTM D7315 - Standard Test Method for Determination of Turbidity Above 1 Turbidity Unit (TU) in Static Mode

ASTM D6655 - Standard Test Method for Determination of Turbidity Below 5 NTU in Static Mode

Light source Light-emitting diode (LED) at 860 ± 30 nm

Measurement modes FNU, FAU, NTU, EBC, Abs (absorbance), %T (%

transmittance) and two user-defined units

Range FNU (manual range): 0–0.999, 0–9.99, 0–99.9, 0–1000

FNU (auto range): 0–1000

FAU (manual range): 20–99.9, 20–10,000

FAU (auto range): 20–10,000

NTU (Ratio on, manual range): 0–0.999, 0–9.99, 0–

99.9, 0–10,000

NTU (Ratio on, auto range): 0–10,000 auto decimal

NTU (Ratio off): 0–40

EBC (Ratio on, manual range): 0–0.999, 0–9.99, 0–

99.9, 0–2450

EBC (Ratio on, auto range): 0–2450 auto decimal

EBC (Ratio off): 0–9.8

Absorbance (manual range): 0–0.999, 0–2.00

Absorbance (auto range): 0–2.00

Transmittance (%): 1.0–100

Specification Details

Accuracy1, 2,

Resolution Turbidity: 0.001 FNU/NTU/EBC

Repeatability ±1% of reading or 0.01 FNU, whichever is greater

Response time Signal averaging off: 6.8 seconds

Stabilization time Immediately

Reading modes Manual or auto range, signal averaging on and

Power requirement 115–230 VAC, 50/60 Hz (automatic power selection)

Pollution degree/installation category

Protection Class 1

Operating conditions Temperature: 0 to 40 °C (32 to 104 °F)

Storage conditions –40 to 60 °C (–40 to 140 °F), instrument only

FNU4: ±2% of reading plus 0.01 FNU from 0–1000 FNU

FAU: ±10% of reading from 20–10,000 NTU

NTU4: ±2% of reading plus 0.01 NTU from 0– 1000 NTU, ±5% of reading from 1000–4000 NTU, ±10% of reading from 4000–10,000 NTU

Absorbance: ±0.005 Abs from 0–1 Abs at 860 nm

Transmittance: 0.12% T from 10–100% T at 860 nm

Absorbance: 0.001 Abs

Transmittance: 0.1% T

(under reference conditions)

Signal averaging on: 14 seconds (when 10 measurements are used to calculate the average)

adjustable or off, Ratio on or off

28 W maximum

2; II

Relative humidity: 0–90% at 25 °C, 0–75% at 40 °C, noncondensing

Altitude: 2000 m (6560 ft) maximum

Indoor use only

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Specification Details

Printer Built-in (thermal, 58-mm, up to 28 column)

Interface RS232C serial interface by way of DB9 subminiature D-

Air purge Dry nitrogen or instrument grade air (ANSI MC 11.1,

Sample cells Round cells 95 x 25 mm (3.74 x 1 in.) borosilicate glass

Sample requirements 25 mm sample cell: 20 mL minimum

Enclosure High-impact polycarbonate plastic

Dimensions 30.5 x 40 x 15.6 cm (12.0 x 15.7 x 6.1 in.)

Weight 3.8 kg (8.5 lb)

Certification CE, cETLus

Turbidity specifications identified using recently prepared formazin standard and matched 25-mm sample cells.

Reference conditions: 23 ± 2 °C, 50% ± 10% RH noncondensing, 115/230 VAC, 50/60 Hz

Intermittent electromagnetic radiation of 3 volts/meter or greater may cause slight accuracy shifts.

FNU is equivalent to NTU in the Ratio off mode.

shell connector for data output to computer or printer, and data input (command). No handshaking.

1975)

0.1 scfm at 69 kPa (10 psig); 138 kPa (20 psig) maximum

Hose barb connection for 1/8-inch tubing

with rubber-lined screw caps

Note: Smaller sample cells (less than 25 mm) can be used when a cell adapter is used.

0 to 95 °C (32 to 203 °F)

Note: Refer to Use a cell adapter on page 34 for the minimum sample size when not using a 25 mm sample cell.

General information

In no event will the manufacturer be liable for direct, indirect, special, incidental or consequential damages resulting from any defect or omission in this manual. The manufacturer reserves the right to make

changes in this manual and the products it describes at any time, without notice or obligation. Revised editions are found on the manufacturer’s website.

Safety information

N O T I C E

The manufacturer is not responsible for any damages due to misapplication or misuse of this product including, without limitation, direct, incidental and consequential damages, and disclaims such damages to the full extent permitted under applicable law. The user is solely responsible to identify critical application risks and install appropriate mechanisms to protect processes during a possible equipment malfunction.

Please read this entire manual before unpacking, setting up or operating this equipment. Pay attention to all danger and caution statements. Failure to do so could result in serious injury to the operator or damage to the equipment.

Make sure that the protection provided by this equipment is not impaired. Do not use or install this equipment in any manner other than that specified in this manual.

Use of hazard information

D A N G E R

Indicates a potentially or imminently hazardous situation which, if not avoided, will result in death or serious injury.

Indicates a potentially or imminently hazardous situation which, if not avoided, could result in death or serious injury.

Indicates a potentially hazardous situation that may result in minor or moderate injury.

Indicates a situation which, if not avoided, may cause damage to the instrument. Information that requires special emphasis.

W A R N I N G

C A U T I O N

N O T I C E

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Precautionary labels

Read all labels and tags attached to the instrument. Personal injury or damage to the instrument could occur if not observed. A symbol, if noted on the instrument, will be included with a danger or caution statement in the manual.

This symbol, if noted on the instrument, references the instruction manual for operation and/or safety information.

Electrical equipment marked with this symbol may not be disposed of in European public disposal systems after 12 August of 2005. In conformity with European local and national regulations (EU Directive 2002/96/EC), European electrical equipment users must now return old or end-of-life equipment to the Producer for disposal at no charge to the user.

Note: For return for recycling, please contact the equipment producer or supplier for instructions on how to return end-of-life equipment, producer-supplied electrical accessories, and all auxiliary items for proper disposal.

Certification

Canadian Radio Interference-Causing Equipment Regulation, IECS-003, Class A:

Supporting test records reside with the manufacturer.

This Class A digital apparatus meets all requirements of the Canadian Interference-Causing Equipment Regulations.

Cet appareil numèrique de la classe A respecte toutes les exigences du Rëglement sur le matériel brouilleur du Canada.

FCC Part 15, Class "A" Limits

Supporting test records reside with the manufacturer. The device complies with Part 15 of the FCC Rules. Operation is subject to the following conditions:

1. The equipment may not cause harmful interference.

2. The equipment must accept any interference received, including

interference that may cause undesired operation.

Changes or modifications to this equipment not expressly approved by the party responsible for compliance could void the user's authority to operate the equipment. This equipment has been tested and found to comply with the limits for a Class A digital device, pursuant to Part 15 of the FCC rules. These limits are designed to provide reasonable protection against harmful interference when the equipment is operated in a commercial environment. This equipment generates, uses and can radiate radio frequency energy and, if not installed and used in accordance with the instruction manual, may cause harmful interference to radio communications. Operation of this equipment in a residential area is likely to cause harmful interference, in which case the user will be required to correct the interference at their expense. The following techniques can be used to reduce interference problems:

1. Disconnect the equipment from its power source to verify that it is or

is not the source of the interference.

2. If the equipment is connected to the same outlet as the device

experiencing interference, connect the equipment to a different outlet.

3. Move the equipment away from the device receiving the interference.

4. Reposition the receiving antenna for the device receiving the

interference.

5. Try combinations of the above.

Product overview

The 2100AN IS laboratory turbidimeter measures turbidity in FNUs (Formazin nephelometric units), NTUs (nephelometric turbidity units) and EBCs (European Brewing Convention units). NTUs and EBCs are calculated using the conversion factors of 1.0 NTU per 1.0 FNU and

0.245 EBCs per 1.0 FNU. The 2100AN IS turbidimeter also measures attenuation (FAU), absorbance and transmittance.

In addition, two user-defined measurement units can be specified. Refer to Application specific methods on page 41. The application specific mode of operation uses the nephelometric optical system and the NTU measurement mode.

The turbidimeter has a built-in printer and an RS232 output for connection to a printer, data logger or computer and a recorder output.

English

The turbidimeter contains a real-time clock with battery. The clock provides a time-date stamp on all data transmitted to the built-in printer or to external devices by way of the RS232 interface (i.e., measurements and calibration records).

Figure 1 Front overview

Figure 2 Back overview

1 Power cord connector 5 Air purge fitting

2 Fuse holder 6 Recorder output jack for a chart

3 Power switch 7 Remote cable jack for flow valve

4 DB9 connector for RS232 cable

recorder (0 to 1 V output)

module connection to the automatic flow cell (low pressure)

1 Mode display: shows the calibration

standard number, setup number or sample number

2 Keypad 6 Printer cover

3 Sample cell holder 7 Eight-digit LED display

4 Light shield

5 Cover for the sample cell

compartment

8 English

Product components

Refer to Figure 3 to make sure that all components have been received. If any of these items are missing or damaged, contact the manufacturer or a sales representative immediately.

Figure 3 Instrument components

1 2100AN IS turbidimeter 6 Gelex® secondary turbidity

2 Oiling cloth 7 Dust cover

3 Six 1" sample cells (30 mL) with

caps

4 Silicone oil 9 Power cord

5 StablCal® Calibration kit

Supplied with 4790100 only.

Do not remove the plastic wrapper from the paper rolls until the paper is installed.

standardization kit

8 Printer paper roll (2x)

Installation

Put paper in the printer

N O T I C E

Use only the provided thermal paper. Use of other thermal paper may cause poor print quality and decrease the life of the print-head.

Notes:

• Do not rub the thermal paper with a hard object.

• Do not use chemical paste on thermal paper.

• A red line on the edge of the thermal paper shows when the paper supply is low.

1. Cut the end of the paper with scissors to make an arrow shape.

2. Open the printer cover.

3. Put the point of the thermal paper in the paper entrance slot.

4. Push the paper through until the point of the paper comes out the

exit slot.

5. Pull the paper out of the exit slot until the full width of the paper is

past the exit slot.

6. Put the paper roll in the printer.

7. Put the thermal paper through the slot in the printer cover, then close

the printer cover.

D A N G E R

Multiple hazards. Only qualified personnel must conduct the tasks described in this section of the document.

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User interface

Figure 4 Keypad

1 ENTER key 7 FLOW key

2 EDIT (arrow) keys 8 SIGNAL AVG key

3 SAMPLE key 9 PRINT key

4 RANGE key 10 LINE FEED key

5 UNITS/Exit key 11 SETUP key

6 RATIO key 12 CAL/Zero key

Table 1 Key descriptions

Key Description

Enters the value on the display. Starts the measurement of a calibration standard. Clears data from the buffer.

Table 1 Key descriptions (continued)

Key Description

Starts the changing of the sample number shown on the mode display.

Selects automatic or manual ranging.

Selects the unit of measure. Exits Calibration or Setup mode without saving changes.

Turns Ratio on or off.

Turns on or off the Flow mode of operation. Used only with the automated flow cell.

Turns signal averaging on or off.

Sends the data that is on the display to a printer or computer. Sends a calibration data report to a printer or computer when in Calibration mode. Sends diagnostic results to a printer or computer if held down when the instrument is turned on. Provides a print of the setup commands when in Setup mode. Turns the print interval feature on or off if the instrument has been configured with a printer interval.

Moves the printer paper forward one line.

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Changes the numbers and/or letters on the display. Steps through the calibration standards. The right arrow key moves the cursor to the previous or next digit.

Turns on Setup mode and starts the selection of the setup number on the mode display.

Starts a calibration when in FNU, FAU, NTU or EBC mode. Starts analytical zeroing when in %T or Abs mode.

Figure 5 Indicator lights

1 Lamp icon light 7 PRINT light

2 "CAL?" light 8 SIGNAL AVG light

3 "Manual" light 9 CAL/Zero light

4 "Auto" light 10 SETUP light

5 RATIO light 11 SAMPLE light

6 FLOW light

Table 2 Light descriptions

Light Description

Illuminated when the instrument light source is on.

Flashes when there is not sufficient light for measurement.

CAL? "CAL?" is shown during a calibration if the calibration data is not

within the acceptable range.

Flashes when the instrument should be calibrated.

Note: The CAL? light applies when a 25-mm sample cell is used. Ignore the CAL? light if illuminated during calibration when a smaller sample cell is used. Push UNITS/Exit to start measurements.

Manual "MANUAL" is shown above the Range Mode label when the

RATIO Illuminated when Ratio is on.

FLOW Illuminated when the Flow mode of operation is selected.

PRINT Illuminated when the printer interval feature is selected.

SIGNAL

SETUP Illuminated when Setup mode is selected.

SAMPLE Illuminated when Sample mode is selected.

instrument is in manual ranging mode.

Auto "AUTO" is shown below the Range Mode label when the instrument is

in auto ranging mode.

Flashes when the flow cycle is done.

Flashes when a print interval has been selected but is not active.

Illuminated when signal averaging is on.

AVG

CAL

Illuminated when Calibration or Zeroing mode is selected.

Zero

English 11

Startup

Set the date and time

Turn the instrument on

C A U T I O N

Infrared Light Hazard. The infrared light produced by this instrument can cause eye injury. The infrared light source in this instrument only receives power when the sample cell cover is closed.

1. Put the instrument on a stable, level surface that is free of vibration.

Do not put in direct sunlight.

2. Make sure that there is air circulation around the instrument. Keep

the back and area below the instrument free of material that could decrease air flow through the vents.

3. Connect the power cord to the power plug on the back of the

instrument.

4. Connect the power cord to a power socket with ground contact.

5. Push the power switch on the back of the instrument to turn the

instrument on.

Turn the keypad sound off (optional)

By default, the instrument makes an audible sound when a key is pushed. To turn the keypad sound off:

1. Push SETUP. The SETUP light turns on.

2. Use the arrow keys to select 00.

3. Push ENTER.

4. Use the arrow keys to select the sound option:

Option Description

BEEP ON An audible sound is made when a key is pushed.

BEEP OFF No sound is made when a key is pushed.

5. Push ENTER.

6. Push SETUP.

1. Push SETUP. The SETUP light turns on.

2. Use the arrow keys to select an option:

Option Description

05 Sets the hours and minutes (HH-MM).

06 Sets the month and day (MM-DD).

07 Sets the year (YY).

3. Push ENTER.

4. Use the arrow keys to change the value.

5. Push ENTER.

6. Push SETUP.

Show the current time (optional)

1. Push SETUP. The SETUP light turns on.

2. Use the arrow keys to select 08.

3. Push ENTER. The current time is shown on the display (HH-MM-

SS).

4. Push SETUP.

Standard operation

Calibrate the turbidimeter with StablCal® Standards

Calibrate the turbidimeter before it is used for the first time using the StablCal® sealed vial standards provided. As an alternative, calibration can be done with recently prepared formazin standards. Refer to

Calibrate the turbidimeter with formazin standards on page 37.

Calibrate the turbidimeter at least every 3 months or as specified by the regulating authority when data is used for ISO 7027 reporting.

Note: Unknown results may occur if standards other than the recommended calibration points are used. The recommended calibration points (< 0.1, 20, 200, 1000, 4000 and 7500 NTU) provide the best calibration accuracy. Use of standards

English

other than StablCal, or user-prepared formazin, may result in less accurate calibrations. The manufacturer cannot guarantee the performance of the instrument if calibrated with co-polymer styrenedivinylbenzene beads or other suspensions.

Prepare the StablCal standards

When received and at intervals:

1. Clean the exterior surface of the StablCal vials with laboratory glass

cleaning detergent.

2. Rinse the vials with distilled or deionized water.

3. Dry the vials with a lint-free cloth.

Note: Never shake or invert the < 0.1 NTU standard. If the standard has been mixed or shaken, do not move the vial for 15 minutes or more before using.

Note: Do not remove the caps from the sealed vials.

Make sure that the StablCal standards are at ambient instrument temperature before use (and no greater than 40 °C (104 °F)).

Mix the standards before use:

1. Open the case lid. Remove the < 0.1 NTU standard from the plastic

case.

2. Leave the other standards in the case. Close the case lid.

3. Shake the case vigorously for at least 10 seconds.

4. Let the standards stand with no movement for 3–5 minutes before

use.

Calibration notes

• Make sure that the instrument is in the same ambient conditions as where it is used.

• Make sure that the standards are at the same ambient temperature as the instrument before use.

• Use only the provided silicone oil. This silicone oil has the same refractive index as the vial glass and masks minor glass differences and scratches.

• Store the oiling cloth in a plastic storage bag to keep the cloth clean.

• If power is lost during calibration, the new calibration data is lost and the last calibration data is used. To exit a calibration and not save the new values, push UNITS/Exit.

• In Calibration mode, automatic range and signal averaging on are selected. When calibration is completed, all operational modes go back to the last settings.

• All nephelometric (turbidity units of measure) calibrations are done at the same time.

• Ratio-on and Ratio-off calibration data is measured and recorded at the same time.

• The 4000-NTU and 7500-NTU standards do not have to be measured during calibration if FNUs will be measured. Push CAL/Zero after the 1000 NTU standard is measured to complete the calibration procedure.

• The 7500-NTU standard does not have to be measured during calibration if turbidity less than 4000 NTU will be measured. Push CAL/Zero after the 4000 NTU standard is measured to complete the calibration procedure.

• The FNU values of StablCal standards and formazin standards are calculated using the conversion factors of 1 FNU = 1 NTU.

English 13

StablCal calibration procedure

1. Push CAL/Zero.

The CAL/Zero light turns on, and the mode display shows "00". The NTU value of the dilution water that was used in the previous calibration is shown on the display.

7. Remove the vial from the sample cell holder.

14 English

2. Get the < 0.1 NTU

vial. Clean the vial with a soft, lint-free cloth to remove water spots and fingerprints. Do not invert the vial.

8. Do steps 5–10 for the other StablCal vials (from lowest to highest NTU standard).

The mode display shows "00" after the last vial is measured.

3. Apply a small bead of silicone oil from the top to the bottom of the vial.

9. Push CAL/Zero.

The instrument saves the new calibration data and goes back to Measurement mode.

4. Use the oiling cloth to apply the oil equally to the surface of the vial. Remove the excess oil. Make sure that the vial is almost dry.

5. Put the vial in the sample cell holder with the triangle on the vial aligned with the reference mark on the sample cell holder. Close the cover.

6. Push ENTER.

The instrument display counts down, then measures the standard.

The next expected standard (e.g., 20.00) is shown. The mode display shows "01".

StablCal standards storage

instrument due to small differences in glass and instrument optical systems.

• Do not move a StablCal standard to a different container for storage. Keep StablCal standards in the plastic case provided with the cover closed.

• Store at 5 to 25 °C (41 to 77 °F).

• For long-term storage (more than one month between use), keep at 5 °C (41 °F).

• Do not keep a Gelex vial in the instrument for more time than is necessary to complete measurement. The heat from the lamp can change the turbidity value of a Gelex vial.

• Keep the Gelex standards at room temperature. Do not let Gelex standards freeze or become warmer than 50 °C (122 °F). High temperatures may cause Gelex suspensions to divide.

• Make sure that the Gelex standards are at ambient instrument

Using Gelex secondary standards

temperature before measurement.

The Gelex secondary standards are used when a calibration check or an optical system check is done. Refer to Calibration verification on page 17 and Optical system check on page 17.

Gelex notes

• Measure the Gelex secondary standards on the instrument on which they will be used. The measured values can only be used for one

Measure the Gelex stray light standard

Measure the Gelex stray light standard when the instrument is first received. Record the value on the Gelex vial with a permanent marker one time.

1. Clean the stray light

standard with a soft, lint-free cloth to remove water spots and fingerprints.

2. Apply a small bead of silicone oil from the top to the bottom of the vial.

3. Use the oiling cloth to apply the oil equally to the surface of the vial. Remove the excess oil. Make sure that the vial is almost dry.

4. Push RANGE to select automatic ranging.

"AUTO" is shown below the Range Mode label on the instrument.

5. Push SIGNAL AVG to turn signal averaging off.

The SIGNAL AVG light turns off.

6. Push UNITS/Exit to select the NTU measurement mode.

English 15

7. Push RATIO to turn

Ratio mode on.

8. Put the stray light standard in the sample cell holder with the triangle on the vial aligned with the reference mark on the sample cell holder. Close the cover.

9. Read the value when stable. Remove the vial from the instrument.

10. Record the value on the white diamond space on the vial using a permanent marker.

Measure the Gelex secondary turbidity standards

Measure the Gelex secondary turbidity standards each time the instrument is calibrated and record the new values on the Gelex vials with a water soluble marker.

1. Clean the Gelex vials with a soft, lint-free cloth to remove water spots and fingerprints.

16 English

2. Apply a small bead

of silicone oil from the top to the bottom of the vial.

3. Use the oiling cloth to apply the oil equally to the surface of the vial. Remove the excess oil. Make sure that the vial is almost dry.

4. Push RANGE to select automatic ranging.

"AUTO" is shown below the Range Mode label on the instrument.

5. Push SIGNAL AVG to turn signal averaging off.

The SIGNAL AVG light turns off.

6. Push UNITS/Exit to select the NTU measurement mode.

7. Push RATIO to

select Ratio on or off.

Ratio must be on for Gelex standards greater than 40 NTU. For the 0–2 and 0– 20 NTU Gelex standards, select the Ratio function that the instrument will operate in.

8. Put the 0–2 NTU Gelex vial in the sample cell holder with the triangle on the vial aligned with the reference mark on the sample cell holder. Close the cover.

9. Read the value when stable. Remove the vial from the instrument.

10. Record the value on the white diamond space on the vial using a water soluble marker.

Record on the vial if Ratio was on or off when the vial was measured.

11. Do steps 7–10 for the other Gelex vials (but not the stray light standard). Measure from lowest to highest NTU.

Calibration verification

At intervals, measure the Gelex secondary turbidity standard that is closest in value to the turbidity range to be measured. Do the steps in

Measure the Gelex secondary turbidity standards on page 16, but do not

change the value that is recorded on the vial.

Turn Ratio on if the Gelex vial is greater than 40 NTU. Select the Ratio setting recorded on the Gelex vial for vials less than 40 NTU.

If the measured value is within ±5% of the value recorded on the Gelex vial, calibration is verified. If not, calibrate the instrument.

Note: The StablCal® primary turbidity standards can also be used to do a calibration check. Prepare the StablCal vials before use. Refer to Prepare the

StablCal standards on page 13. Do not use the < 0.1 NTU StablCal vial as it does

not have an accurately identified NTU value. The instrument is calibrated if the measured value is within ±5% of the StablCal value.

Optical system check

At intervals, measure the Gelex stray light standard to inspect the integrity of the optical system. Do the steps in Measure the Gelex stray

light standard on page 15, but do not change the value that is recorded

on the vial.

If the value measured is similar to the value recorded on the Gelex stray light standard (within ±0.02 NTU), the instrument works correctly. If not, contact Customer Service.

Prepare a sample cell

Use a clean sample cell(s) for sample measurement.

Note: As an alternative, a flow cell can be used for sample measurement. Refer to

Using a flow cell on page 30.

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Clean the sample cell

C A U T I O N

Chemical exposure hazard. Obey laboratory safety procedures and wear all of the personal protective equipment appropriate to the chemicals that are handled. Refer to the current material safety data sheets (MSDS) for safety protocols.

N O T I C E

Do not air dry the sample cells. Always store the sample cells with caps on to prevent the cells from drying. For storage, fill the sample cell with distilled or demineralized water.

1. Clean the internal and external surfaces of the sample cell and cap

with a laboratory glass cleaning detergent.

2. Fully rinse the sample cell many times with distilled or deionized

water.

3. Clean the internal and external surfaces of the sample cell and cap

with 1:1 hydrochloric acid.

4. Fully rinse the sample cell many times with distilled or deionized

water.

Note: If the sample cell will be used to measure low range turbidity samples or dilution water, rinse with dilution water (not distilled or deionized water). Refer to Prepare dilution water on page 23.

5. Dry the external surface of the sample cell with a soft, lint-free cloth.

6. Fill the sample cell with distilled or deionized water.

Note: If the sample cell will be used to measure low range turbidity samples or dilution water, fill the sample cell with dilution water (not distilled or deionized water).

7. Immediately put the cap on the sample cell.

Note: Hold the sample cell by the top only to minimize dirt and fingerprints.

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Indexing a single sample cell

When measuring very low turbidity samples, use a single indexed sample cell or a flow cell for all measurements to get precise and repeatable measurements. As an alternative, optically matched sample cells can be used. Refer to Matching sample cells on page 21. Matched sample cells do not provide as good of accuracy and precision as a single indexed sample cell that is used for every measurement or a flow cell.

1. Rinse a clean,

empty sample cell two times with dilution water and drain to waste. Fill the sample cell to the line (about 30 mL) with dilution water and immediately put the cap on the sample cell. Refer to Prepare

dilution water

on page 23.

Let the sample cell sit for at least five minutes to degas.

2. Clean the sample cell with a soft, lint-free cloth to remove water spots and fingerprints.

3. Apply a small bead of silicone oil from the top to the bottom of the sample cell.

4. Use the oiling cloth provided to apply the oil equally to the surface of the sample cell. Remove the excess oil. Make sure that the sample cell is almost dry.

5. Put the sample cell in the sample cell holder. Close the cover.

Record the value when stable.

6. Remove the sample cell, turn it about 1/8 of a turn and put it in the sample cell holder again. Close the cover.

Record the value when stable.

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7. Repeat step 6 until

the lowest value is shown on the display.

8. Put an orientation mark on the marking band near the top of the sample cell where the lowest value is shown.

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Matching sample cells

To decrease the effects that optical differences among sample cells can have on turbidity, transmittance or absorbance measurements, measure samples in matched sample cells. It may not be possible to match all sample cells due to the differences in glass.

1. Rinse two or more

clean, empty sample cells two times with dilution water and drain to waste. Fill the sample cells to the line (about 30 mL) with filtered dilution water and immediately put the cap on the sample cell. Refer to Prepare

dilution water

on page 23.

Let the sample cell sit for at least five minutes to degas.

2. Clean the sample cells with a soft, lint-free cloth to remove water spots and fingerprints. Do not invert the sample cell.

3. Apply a small bead of silicone oil from the top to the bottom of the sample cells.

4. Use the oiling cloth provided to apply the oil equally to the surface of the sample cells. Remove the excess oil. Make sure that the sample cells are almost dry.

5. Put the first sample cell in the sample cell holder. Close the cover.

Record the value when stable.

6. Remove the sample cell, turn it about 1/8 of a turn and put it in the sample cell holder again. Close the cover.

Record the value when stable.

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7. Repeat step 6 until

the lowest value is shown on the display.

13. Do steps 9– 12 again as necessary to match the other sample cells prepared in steps 1–4.

8. Record the value. Put an orientation mark on the marking band near the top of the sample cell.

9. Put the second sample cell in the sample cell holder. Close the cover.

Record the value when stable.

10. Remove the sample cell, turn it about 1/8 of a turn and put it in the sample cell holder again. Close the cover.

Record the value when stable.

11. Repeat step 10 until the value matches the first sample cell value within ±0.005 FNU.

Note: Match sample cells to within ±0.002 absorbance units when indexing sample cells in the Absorbance mode for use with transmittance or absorbance measurements.

12. Put an orientation mark on the marking band near the top of the sample cell where the lowest value is shown.

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Prepare dilution water

Dilution water is used when indexing a sample cell or matching sample cells and to prepare formazin standards.

1. Collect at least 1000 mL of high-quality, low-turbidity water (i.e.,

distilled, demineralized or deionized water or filtered tap water).

2. Measure the turbidity of the water using the turbidimeter. Refer to

Turbidity measurement on page 25.

3. If the turbidity of the water is greater than 0.5 NTU, filter the water

using the sample filtration and degassing kit. Refer to the user instructions provided with the sample filtration and degassing kit.

Prepare the sample

Proper sampling techniques are important to get accurate measurements.

Prepare a representative sample

A representative sample accurately reflects the true condition of the water source from which the sample was taken.

To prepare a representative sample:

• Gently but fully mix every sample before collecting aliquots (sample portions). Mix by gentle inversion only. Do not shake.

• When collecting a sample from a water tap in a distribution system or treatment plant, turn the water on for at least five minutes, then collect the sample.

• When collecting a sample from a body of water (e.g., a stream or storage tank), collect at least one liter (1 quart) and fully mix before taking an aliquot for measurement. If the quality of the sample source is not constant, collect samples at many locations at different depths as necessary. Then, mix the samples together to prepare one sample for measurement.

Remove air bubbles from the sample

If readings are not stable, air bubbles may be the cause. Remove air or other gases from the sample before measurement even if no bubbles can be seen.

The methods typically used for degassing are:

• Let the sample stand for several minutes

• Apply a vacuum

• Use an ultrasonic bath

• Apply heat

Let the samples stand for several minutes, then gently invert two or three times before measurement.

In some cases, more than one method may be necessary to remove bubbles (e.g., the use of heat with an ultrasonic bath may be necessary in some severe conditions). Use care with these methods as sample turbidity can be changed if these methods are not used correctly.

Apply a vacuum

Apply a vacuum with any available, clean, oil-free vacuum source, such as the sample degassing kit, or an electric or hand-operated pump equivalent to those in Accessories on page 46. The vacuum lowers the atmospheric pressure above the sample letting trapped gas bubbles exit.

Vacuum works well with samples that are not viscous, such as water, and do not contain volatile components. Application of vacuum to viscous, volatile samples (i.e., paint resins) may cause volatile components to come out of solution, and increase the bubbles.

Use an ultrasonic bath

An ultrasonic bath removes gas bubbles from most samples, especially viscous liquids. The time necessary to remove bubbles may be a few seconds to a minute or more.

To identify the time necessary for ultrasonic treatment:

1. Apply ultrasound to the sample for a short period of time, then

measure turbidity. Record the value and the treatment time.

2. Do step 1 again until there is no change in the turbidity of the

sample.

Note: In some instances, the use of ultrasound may divide gas bubbles and make them more difficult to remove.

To use an ultrasonic bath:

1. Fill a clean sample cell with sample. Do not put the cap on the

sample cell.

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2. Put 1/2 to 2/3 of the sample cell into the ultrasonic bath and let it stand

until visible bubbles are removed.

3. Remove the sample cell from the ultrasonic bath and put the cap on.

4. Fully dry the sample cell.

Apply heat

C A U T I O N

Make sure that the cap on the sample cell is loose. Increasing the temperature of a tightly-capped sample cell may cause an explosion. More caution should be taken when increasing the temperature of volatile compounds.

If possible, do not use heat to accelerate degassing. Heat may change the properties of the suspended particles and cause volatile components to come out of the solution.

Gentle heat may be used to remove bubbles from very viscous samples when used with vacuum or ultrasound. If applying heat to the sample is necessary, do so only as much as is necessary to complete degassing. Before measurement, decrease the temperature of the sample to the initial temperature, then gently invert the sample.

Prevent condensation on a sample cell

Condensation may occur on the outside of the sample cell when measuring a cold sample in a warm, humid environment. This condensation or fogging of the sample cell interferes with turbidity measurement.

To prevent condensation:

• Make sure that the outside of the sample cell is dry before measurement.

• Use the air purge system as necessary. Refer to Using the air purge

system on page 29.

• If condensation occurs while using the air purge system, warm the sample slightly. Let the sample sit at room temperature or partially put the sample into a warm water bath for a short time. Gently invert the sample cell before measurement.

Note: Warming may change the sample turbidity. Measure the sample without warming when possible.

Measure over-range samples

The nephelometric method of turbidity measurement depends on light scattering from suspended particles. If turbidity is very high, significant amounts of light may be absorbed by the particles, and little light is available for scattering. This results in a negative interference causing the measured turbidity to be lower than the actual turbidity. This condition is called “going blind”.

Methods used to prevent the instrument from going blind include:

• Turn Ratio on. Ratio on mode decreases the effects of light absorbing particles, color, absorbance and high turbidity interferences.

• If measuring in the FNU mode, change the measurement units to NTU by pushing UNITS/Exit. The NTU measurement mode (with Ratio on) increases the measurement range.

• Sample dilution. Refer to Sample dilution on page 24.

When too much light is absorbed by the sample, the lamp icon on the instrument display flashes.

Sample dilution

Use filtered sample, deionized water or distilled water for sample dilution. Measure sample dilutions soon after they are prepared.

To prepare filtered sample, use the sample filtration and degassing kit. Refer to the user instructions provided with the sample filtration and degassing kit.

If the filters in the sample filtration and degassing kit plug quickly, use a standard 47 mm filtration apparatus shown in Figure 6 with a membrane filter or use a glass-fiber filter. Refer to Accessories on page 46.

After dilution and measurement, calculate the actual turbidity as follows:

1. Calculate the total volume:

Total volume = sample + dilution water

Example: 20 mL of sample and 80 mL of dilution water

Total volume = 20 mL + 80 mL = 100 mL

2. Calculate the dilution factor:

Dilution factor = total volume ÷ sample volume

Example: Dilution factor = 100 ÷ 20 = 5

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3. Calculate the actual turbidity:

Actual turbidity = measured value × dilution factor

Example: Measured value = 2450 NTU

Actual turbidity = 2450 × 5 = 12,250 NTU

Figure 6 Prepare filtered sample using membrane or glass-fiber filter

1 Filter pump 4 Stopper 7 Filter

2 Hose 5 Filter holder

3 Filter flask 6 Tweezers

Turbidity measurement

W A R N I N G

Potential explosion and fire hazard. This instrument is for measuring water based samples. Do not measure solvent or combustible based samples.

For accurate turbidity readings use clean sample cells and remove air bubbles. Refer to Clean the sample cell on page 18 and Remove air

bubbles from the sample on page 23.

Measurement notes

Proper measurement techniques are important in minimizing the effects of instrument variation, stray light and air bubbles. For accurate and repeatable measurements:

Instrument

• Make sure that the instrument is on a level, stationary surface that is free of vibration during the measurement.

• Instrument stabilization is immediate. No warm-up time is necessary.

• Always close the sample compartment lid during measurement, calibration and storage.

• Remove the sample cell from the instrument and turn off the instrument if the instrument is stored for an extended time period (more than a month).

• Keep the sample compartment lid closed to keep dust and dirt out.

Sample cells

• Always cap the sample cell to prevent spillage of the sample into the instrument.

• Always use clean sample cells in good condition. Dirty, scratched or damaged cells can result in readings that are not accurate.

• Make sure that cold samples do not “fog” the sample cell. Refer to

Prevent condensation on a sample cell on page 24.

• Store sample cells filled with distilled or deionized water and cap tightly.

• For the best accuracy, use a single sample cell for every measurement or a flow cell.

Note: As an alternative, matched sample cells may be used for measurements but do not provide as good of accuracy or precision as a single indexed sample cell or flow cell. When using matched sample cells, align the orientation mark on the sample cell with the reference mark on the sample cell holder.

Measurement

English

• Measure samples immediately to prevent temperature changes and settling. Before a measurement is taken, always make sure that the sample is homogeneous throughout.

Turbidity measurement procedure

• Avoid sample dilution when possible.

• Avoid instrument operation in direct sunlight.

1. Rinse a clean,

empty sample cell two times with the solution to be measured and drain to waste. Fill to the line (about 30 mL) with sample and immediately put the cap on the sample cell.

7. Read and record the

value when stable.

Note: To print or send (via RS232) a measurement record, push PRINT.

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2. Clean the sample

cells with a soft, lint-free cloth to remove water spots and fingerprints.

3. Apply a small bead of silicone oil from the top to the bottom of the sample cells.

4. Use the oiling cloth provided to apply the oil equally to the surface of the sample cells. Remove the excess oil. Make sure that the sample cells are almost dry.

5. Gently and slowly invert the sample cell to fully mix the sample. Be careful not to add air bubbles.

6. Put the sample cell in the sample cell holder with the triangle on the sample cell aligned with the reference mark on the sample cell holder. Close the cover.

Absorbance and transmittance measurement

Measurement notes

For the best accuracy and reproducibility:

• Absorbance and transmittance can only be measured at 860 nm.

• Set the zero reference point before measurement. Set the zero reference point again when a measurement is not taken for several hours as shown in Absorbance and transmittance measurement

procedure on page 27.

• Transmittance and absorbance measurements use the same zero

single sample after setting a zero reference point in one of the two modes.

• Use a flow cell for measurements. A flow cell is necessary to get the accuracy and reproducibilty specifications shown in Specifications on page 5.

If a flow cell is not used, use a single indexed sample cell or match sample cells. Sample cells should be matched using the Transmittance or Absorbance modes. Refer to Matching sample cells on page 21.

• Refer to Measurement notes on page 25 for more measurement notes.

reference point. Absorbance and transmittance can be measured on a

Absorbance and transmittance measurement procedure

Note: To measure samples with negative absorbance, set the analytical zero using the sample with the greatest absorbance, and measure the sample with the least absorbance. Report the reading as negative absorbance.

1. Push UNITS/Exit until "%T" or "ABS" is shown on the display.

2. Using the manual flow cell kit, install the flow cell. Refer to Using

a flow cell

on page 30.

Note: The sample cell cover does not close when the flow cell is installed.

3. Slowly put 250 mL of 100 %T or zero absorbance reference solution down the interior edge of the inlet reservoir.

Put the sample down the interior edge of the reservoir to prevent air bubbles in the sample.

4. Push CAL/Zero.

The display shows "100 %T" or zero.

Note:

The instrument starts analytical zeroing for transmittance, and absorbance modes at the same time.

5. Push ENTER.

The instrument display counts down from 30 to

Note: If the value shown is not 100 %T,

0.000 A, or if dashes flash, do steps 5 and 6 again.

6. Slowly put 250 mL of the sample in the inlet reservoir.

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7. After the sample

flow stops and the display stabilizes, read and record the value.

Note: To print or send (via RS232) a measurement record, push PRINT.

Measurement techniques

Measurements may be made with different operation mode settings and optional accessories.

Calibrate the instrument whenever the sample cell pathlength is changed.

Manual or automatic ranging

The manufacturer recommends that ranging be set to automatic for most measurements.

The setting can be changed at any time during sample measurement.

Push RANGE repeatedly to step the instrument from automatic ranging to manual ranging and then scroll through the manual range settings.

"MANUAL" is shown above the Range Mode label on the instrument when manual ranging is selected. "AUTO" is shown below the Range Mode label on the instrument when automatic ranging is selected.

Notes:

• When manual ranging is selected, the display flashes all 9s when the sample being measured is greater than the selected range. The

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display flashes all 0s when the sample measured is less than the selected range.

• When automatic ranging is selected, the display flashes 9s when the sample is greater than the maximum range of the instrument. The display flashes 9s when Ratio is off and the measurement is greater than 40 NTUs (1000 FNUs or 9.8 EBCs). Turn Ratio on to increase the range. Refer to Measure over-range samples on page 24.

• When automatic ranging is selected, the display flashes all 0s when the measurement is less than the range of the instrument (i.e., less than 20 FAU) or a negative value. Calibrate the instrument. When measuring absorbance or transmittance, set the zero reference point again.

Signal averaging on or off

Signal averaging corrects for reading fluctuations that are caused by random drifting particles in the sample. When signal averaging is on, an average reading is calculated every 3 seconds and shown on the display.

The manufacturer recommends that signal averaging be on for most measurements.

Push SIGNAL AVG to turn signal averaging on or off. The SIGNAL AVG light turns on when signal averaging is on.

Push ENTER when signal averaging is on to erase data in the signal averaging buffer and provide an immediate update on the display as necessary. This is especially useful when measuring samples with large differences in turbidity.

To change the number of measurements that are used to calculate the average reading (default=10):

1. Push SETUP. The SETUP light turns on.

2. Select 09 using the arrow keys.

3. Push ENTER.

4. Use the arrow keys to select the number of measurements—1 to 15.

Note: If a number greater than 15 is selected, 15 measurements will be used.

5. Push ENTER.

6. Push SETUP.

Ratio on or off

Ratio on provides very good linearity, calibration stability and a wide measurement range. Ratio on helps correct for interference when color is present in the sample that absorbs at the wavelength of incident light.

The manufacturer recommends that Ratio on be used for most measurements. Ratio must be on to measure samples greater than 40 NTUs (9.8 EBCs).

Ratio can be turned on for NTU, EBC and ASC -1- and -2measurements.

Push RATIO to turn Ratio on or off. The Ratio light is on when Ratio is on.

Notes:

• If the sample being measured is greater than 40 NTU (or equivalent) and Ratio is off, the display will show 9s and the RATIO light will flash. Push RATIO to turn Ratio on and remove the over-range condition.

• Measurements with Ratio on and measurements with Ratio off are almost the same for turbidity measurements that are less than 40 NTU

if interferences caused by color or light absorbing particles are not present.

Using the air purge system

The air purge system is used to keep condensation off the external surface of the sample cell when cold samples are measured.

The air purge system pushes dry air through the optical compartment to keep the outside the sample cell dry. The connection is made at the air purge fitting on the back of the instrument Figure 2 on page 8.

Use dry nitrogen or instrument grade air (ANSI MC 11.1, 1975) at no greater than 138 kPa (20 psig). The manufacturer recommends an air consumption rate of 3 to 10 SCFH (standard cubic feet/hour).

When the sample temperature is about or less than 2 °C (35 °F), use a desiccant dryer and particle filter to make sure that the dew point of the air purge is less than the sample temperature. The air dryer contains silica gel desiccant that turns pink. Replace the desiccant when it turns pink.

If only shop air is available, use a coalescing filter with an automatic drain and a dryer and particle filter to get instrument quality air. Use a coalescing filter that typically operates for greater than 2000 hours. Replace the particle filter when the air dryer is replaced.

Figure 7 and Figure 8 show the methods for connecting the two types of

air supply to the instrument.

Note: The dryer and filter are not necessary if dry nitrogen is used.

Figure 7 Instrument quality air

1 Particle filter (Balston DFU 9933-

05-BQ or equivalent)

2 Air dryer (Balston DAU 9933-

05-101 or equivalent)

3 Pressure regulator

4 Instrument air

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Figure 8 Standard shop air

1 Particle filter 5 Filter (Balston 100-12-BX or

2 Air dryer 6 Auto drain (Balston 20-105 or

3 Coalescing filter/regulator (0–

30 psig)

4 Shop air

equivalent)

7 Filter housing (Balston

FR-920-30 or equivalent)

Using a flow cell

C A U T I O N

Do not use a flow cell with flammable samples or those that contain hydrocarbons, solvents, concentrated acids or concentrated bases that may damage wetted parts of the cells. Conduct tests before use of flow cells if sample compatibility is not known.

Note: Do not use a high pressure flow cell kit with this instrument.

Use a flow cell to increase the speed, accuracy and reproducibility of measurement. The manufacturer especially recommends using a flow cell for low turbidity measurements.

A flow cell must be used to get the accuracy and reproducibility values in

Specifications on page 5 for absorbance or transmittance.

Install a flow cell

1. Fully clean and assemble the flow cell, tubing and stand. Refer to

Clean a flow cell assembly on page 30 and the user instructions

provided with the flow cell.

2. Fill the flow cell and tubing with water and make sure that there are

no leaks or air bubbles.

Note: Air bubbles collect in areas that are not cleaned fully.

3. Clean the exterior surface of the flow cell with a soft, lint-free cloth to

remove water spots and fingerprints.

4. Apply a small bead of silicone oil from the top to the bottom of the

flow cell.

Note: Use only the provided silicone oil. This silicone oil has the same refractive index as the flow cell glass and masks minor glass scratches.

5. Use the oiling cloth provided to apply the oil equally to the surface of

the flow cell. Remove the excess oil. Make sure that the flow cell is almost dry.

Note: Put the oiling cloth in a plastic storage bag to keep the cloth clean.

6. Install the flow cell in the sample cell compartment.

7. Push the inlet and outlet tubes in the slots on the top of the

instrument enclosure so the sample cell cover can be installed. Refer to the user instructions.

8. Put the flow-cell light cover over the flow cell.

Note: The standard sample cell cover of the instrument does not close when the flow cell is installed.

Clean a flow cell assembly

1. Disassemble the flow cell assembly.

2. Clean the inside and outside of the glass parts with a laboratory

glass cleaning detergent. Follow with multiple rinses with distilled or demineralized water.

Note: All tubing, flow cells, and caps in the flow cell assembly can also be steam sterilized.

3. If measuring low turbidity samples, clean the inside and outside of

the glass parts with 1:1 hydrochloric acid and rinse multiple times with dilution water.

4. Fill the sample cell with distilled or demineralized water and

immediately put the caps on the sample cell.

5. Clean the inside and outside of the plastic parts and tubing with

laboratory detergent and warm water.

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Note: At intervals, replace the tubing as contaminants, including microbiological growths, are difficult to remove from the inside surface of the tubing.

6. Air dry the parts after cleaning.

Flow cell maintenance

• Keep all parts of the flow cell assembly clean.

• At intervals, replace all the tubing to make sure that the system is clean. Keep the tubing as short as possible to minimize air locking and lag time of sample flow. Locate the instrument as close to the drain as possible.

Flow cell operation

• Do not use the flow cell for samples that contain large particles that may collect and stop the sample from flowing.

• Slowly put the sample down the interior edge of the inlet reservoir to prevent mixing of the sample, which can cause air bubbles. Air bubbles create a false positive interference in a turbidity measurement.

• If bubbles collect in the flow cell, gently tap the flow cell on a soft surface to remove the bubbles. If bubbles continue to collect in the flow cell, put the glass flow cell in liquid detergent for 24 hours and then rinse fully.

• When measuring many samples of different turbidity, measure the samples in order of the cleanest (lowest turbidity) to the dirtiest (highest turbidity) to prevent contamination from one sample to the next.

• Do not use greater than the recommended maximum sample pressure of 34 kPa (5 psig).

• Keep the drain tubing below the center line of the instrument. If the whole 152 cm (60 in.) length of drain tubing is used, make sure that the end of the drain tubing is at least 46 cm (18 in.) below the center line of the instrument.

• The flow-cell cover must be in place for the LED light source to function.

Flow cell storage

• Install the reservoir cover when the system is not in use to prevent contamination of the system by airborne particles.

• For short-term storage (a few hours), flush the system with distilled or deionized water and leave the flow cell full of the flush water to minimize air locks and build up of residue on the parts.

• For long-term storage, disassemble, fully clean and air dry all parts.

Using a manual flow cell

To set the flow rate, increase the height of the collection drain assembly on the support rod to decrease the flow rate. Make sure that the bottom of the collection drain assembly is no lower than 7.5 cm (3 in.) above the support stand base.

To flush the flow cell, lower the collection drain assembly to the support stand base to flush the flow cell.

Using an automated flow cell

Change the position of the valve-control switch on the flow valve module to control the flow manually. The valve-control switch has three positions:

• Continuous Open—The flow valve is open.

• Closed—The flow valve is closed.

• Momentary Open—The flow valve is open while the switch is pushed down and held to the Momentary Open position. When the switch is released, the switch goes back to the Closed position and the flow valve closes.

Set the valve-control switch to the Closed position for automated operation of the flow valve module. In automated operation, the instrument controls the flow.

Select static or dynamic mode

In automated operation, the instrument can make flowing (dynamic) or not flowing (static) sample measurements.

Static mode:

1. The flow valve opens for the selected fill time. Refer to Select the fill

time on page 32. The flow cell fills and removes the previous

sample from the system.

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2. The flow valve closes when the fill time interval ends. The last portion

of sample flowing through the flow cell is held so that sample volume measurements can be made for the selected measurement time. Refer to Select the measurement time on page 32. A measurement is completed and the display is updated about once every second.

3. The readings on the display of the instrument are sent at the

selected print time interval to the internal printer (and/or through the RS232 output to an external printer or computer). Refer to Configure

the printer output on page 35.

4. At the end of the selected measurement time, the final reading is

held on the display and sent to the internal printer (and/or through the RS232 output to an external printer or computer). The FLOW light flashes.

Dynamic mode:

1. The flow valve opens for the selected fill time. Refer to Select the fill

time on page 32. The flow cell fills and removes the previous

sample from the system.

2. The flow valve stays open when the fill time period ends.

3. Measurements are made on the dynamic (flowing) sample stream as

it moves through the flow cell for the selected measurement time. Refer to Select the measurement time on page 32. A measurement is completed and the display is updated about once every second.

4. The readings on the display of the instrument are sent at the

selected print time interval to the internal printer (and/or through the RS232 output to an external printer or computer). Refer to Configure

the printer output on page 35.

5. After the selected measurement time, the flow valve closes and the

final reading is held on the display. The final reading is sent to the internal printer (and/or through the RS232 output to an external printer or computer). The FLOW light flashes.

Select the fill time

The fill time is the time interval that the flow valve stays open so that sample flows through the flow cell before measurements are taken.

Set the fill time from 0 seconds to 99 minutes and 99 seconds.

A fill time setting of 0 seconds causes the instrument to start measurement immediately.

Use the flow cell specifications in Table 3 to calculate the correct fill time. Make sure that the fill time includes time to fill the system and to fully remove the previous sample from the system.

Table 3 Automated flow cell specifications

Specification Details

System flow rate 250 mL/minute

System volume (from the discharge of the inlet reservoir to the outlet of the flow cell, not including the 350 mL inlet reservoir)

Purge volume 120 mL (fill time = 30 seconds)

A shorter fill time may be used when the same sample is being measured again and again.

30 mL (fill time = 8 seconds)

minimum

Recommended to fully remove the previous sample from the system.

Select the measurement time

The measurement time is the time interval that the instrument measures the sample.

A measurement is completed and the display is updated about once every second.

Set the measurement time from 0 to 99 minutes and 99 seconds (minimum=15 seconds).

A measurement time of 0 provides continuous measurement until FLOW is pushed.

Note: A measurement time of 0 is not recommended for static mode because particles in the sample may settle over time. The measured turbidity may be lower than the actual turbidity.

Measurement notes

Before measurement, select the printer to use and the print time interval. Refer to Configure the printer output on page 35.

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Static or dynamic measurement procedure

1. Push PRINT to turn

the print interval feature on.

The PRINT light turns on.

2. Install the automated flow cell. Refer to Install

a flow cell on page 30.

Note: The sample cell cover does not close when the flow cell is installed.

3. Push FLOW.

The FLOW light turns on.

4. Push the up and down arrow keys to select STAT (static) or

DYN (dynamic).

5. Push ENTER.

The display shows "MM-SS FIL" (or an actual fill time if a fill time has been selected previously).

6. Push the arrow keys to select the fill time.

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7. Push ENTER.

The display shows "MM-SS MEA" (or an actual measurement time if a measurement time has been selected previously).

8. Push the arrow keys to select the measurement time.

9. Push ENTER to open the flow valve and start the fill time interval.

To do the measurement again without the fill time interval, push ENTER.

To do the measurement again with the fill time interval, push FLOW two times, then push

ENTER.

10. When

measurements are complete, push FLOW.

The FLOW light turns off.

11. Push and hold the valve-control switch to the Momentary Open position to drain the flow cell.

Use a cell adapter

Many different test tubes, sample cells and ampules can be used to measure samples when a cell adapter is used. Use a cell adapter when the test tube, sample cell or ampule is less than 25 mm. Refer to

Accessories on page 46 for the available cell adapters.

Use only test tubes and sample cells that are free of significant scratches. Clean and apply silicone oil to all sample cells, test tubes and ampules used with the cell adapters. Refer to Clean the sample cell on page 18.

Note: Performance specifications may be different than shown in Specifications on page 5 when test tubes, sample cells or ampules less than 25 mm are used.

Use a cell adapter when:

• Only a small quantity of sample is available.

• The sample to be measured is in an ampule that cannot be opened.

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Refer to Table 4 for minimum sample sizes.

Table 4 Minimum sample sizes

Test tube size Sample

12 mm 2.5 mL

13 mm 3.5 mL

16 mm 5 mL

19 mm 7 mL

Install a cell adapter

Note: Use the application specific calibration (ASC) ability of the instrument to provide direct reading of results with cell adapters installed. If the ASC ability is not used, a new calibration curve must be developed each time a cell adapter is used.

N O T I C E

Do not force the cell adapter out of the instrument as serious damage can occur.

1. Align the tab on the cell adapter toward the front of the instrument

(Figure 9).

2. Put the cell adapter in the sample cell holder.

3. Calibrate the instrument each time the sample cell diameter is

changed. Calibrate using sample cells of the same path length as the sample cell that will be used to measure samples.

Note: If test tubes are taller than the cover for the sample cell compartment, use the tall light shield provided with the cell adapter.

Figure 9 Install a cell adapter

Remove a cell adapter

1. Carefully pull the cell adapter up until it is half out of the sample cell

holder.

2. Slowly turn the cell adapter 90 degrees counter-clockwise.

3. Pull the cell adapter up to remove it.

Connect to a printer or computer

Use the serial interface (RS232) connector on the back of the instrument to transmit data from the instrument to an external printer or a serial communication port on a computer. Refer to Figure 2 on page 8.

To connect a serial printer to the instrument, use a printer cable assembly that is terminated with a standard 25-pin D connector. A serialto-parallel converter can be used to print to a parallel printer. Data is transmitted to a printer as a 39-character string plus the line feed and carriage return.

To connect a computer to the instrument, use a serial communication cable with a DB9 connector.

Note: Use of the specified cable or equivalent is mandatory for CE compliance (a shielded cable assembly must be used).

Configure the printer output

1. Push SETUP. The SETUP light turns on.

2. Use the arrow keys to select the printer option:

Option Description

01 Sets the printer speed—FAST PRT or SLOW PRT (2.5 second

delay).

02 Sets the printer to use—INTERNAL, EXTERNAL

(RS232 connection) or BOTH.

03 Sets the print time interval for automatic prints of the reading on the

display in minutes and seconds (mm-ss)—00-15 to 99-99 (disable=00-00).

Note: To turn the print interval feature on or off, push PRINT.

04 Sets the printer contrast—0 (darkest print) to 7 (lightest print).

3. Push ENTER.

4. Use the arrow keys to change the value.

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5. Push ENTER.

6. Push SETUP.

Configure the RS232 connection

1. Push SETUP. The SETUP light turns on.

2. Use the arrow keys to select an option:

Option Description

10 Sets the baud rate (default=1200).

11 Sets the character length (default=8).

12 Sets the stop bit (default=1).

13 Sets the parity select (default=NONE).

3. Push ENTER.

4. Use the arrow keys to change the value.

5. Push ENTER.

6. Push SETUP.

Computer (RS232) commands

A communication program (i.e., such as Window Terminal or ProComm Plus) is recommended for computer operation of the instrument. Configure the communication program to the RS232 connection settings. Refer to Configure the RS232 connection on page 36.

Table 5 shows the RS232 command set for the instrument.

Table 5 RS232 command set

Command Description

VAL Gets the current measurement with the measurement units.

LST Gets the calibration standards and coefficients.

DAT Gets the current date.

To change the date, enter DAT=MM/DD/YY (MM=month, DD=day, YY=year), then push Enter.

Table 5 RS232 command set (continued)

Command Description

TIM Gets the current time in 24-hour format.

To change the time, enter TIM=HH:MM (HH=hour, MM=minutes), then push Enter.

RMN Gets the recorder minimum value.

To change the recorder minimum value, enter RMN=XXXXX (XXXXX=a number, minimum value=0), then push Enter.

RMX Gets the recorder maximum value.

To change the recorder maximum value, enter RMX=XXXXX (XXXXX=a number, maximum value=10,000), then push Enter.

RTN Gets the recorder trim minimum value.

To change the recorder minimum value, enter RTN=XXXXX (XXXXX=a number, minimum value=200), then push Enter.

RTX Gets the recorder trim maximum value.

To change the recorder maximum value, enter RTX=XXXX (XXXX=a number, maximum value=4800), then push Enter.

SAV Gets the signal average buffer size.

To change the signal average buffer size, enter SAV=XX (XX=a number, maximum value=15, default=10), then push Enter.

Connect to a data recorder

Note: Use a twisted-pair, shielded recorder cable. Use of non-shielded recorder cable may result in radio wave emission levels greater than is allowed under the compliance regulations listed.

Note: Connect the shield of the recorder cable to the recording device chassis ground terminal to decrease the effects of unwanted interferences.

Connect a ¼–inch recorder phone plug to the recorder output jack on the back of the instrument. Refer to Figure 2 on page 8. For the best performance, use a twisted-pair, shielded recorder cable that is no more than 1.8 m (6 ft) in length with a load impedance greater than 10 kohms.

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Configure the data recorder output

Note: The recorder minimum and maximum values are selected independently for each measurement mode. When the measurement mode changes, the previous settings are automatically used.

1. Push SETUP. The SETUP light turns on.

2. Use the arrow keys to select an option:

Option Description

14 Sets the minimum value of the recorder output for the current

measurements units.

15 Sets the the maximum value of the recorder output for the current

measurement units.

16 Moves the recorder minimum output to calibrate the recorder.

17 Moves the recorder full-scale output to calibrate the recorder.

18 Sets the recorder to zero scale.

19 Sets the recorder to half scale.

20 Sets the recorder to full scale.

3. Push ENTER.

4. If option 14 or 15 was selected, move the decimal point to the correct location using the right arrow key, then push ENTER.

5. Use the arrow keys to change the value.

6. Push ENTER.

7. Push SETUP.

Advanced operation

Calibrate the turbidimeter with formazin standards

The instrument may be calibrated using prepared formazin standards made from 4000-NTU formazin stock solution. Refer to Accessories on page 46.

Note: Use recently prepared formazin standards to get the accuracy specifications for turbidity in Specifications on page 5.

Prepare formazin standards

For the best accuracy and long-term data comparability, use formazin stock solution from Hach to make formazin standards.

Note: As an alternative, a 4000-NTU formazin stock solution that is prepared by the user may be used to make formazin standards. Refer to Making 4000-NTU

formazin stock solution on page 40.

Prepare formazin standards immediately before calibration in an environment that is at the same ambient temperature as the instrument. Discard after use.

Refer to Table 6 for the procedures to make the recommended calibration standards.

Table 6 Formazin standard preparation

Standard Step 1 Step 2 Step 3

20 NTU Add 100 mL of dilution

200 NTU Add 50 mL of dilution

water to a clean 200mL Class A volumetric flask. Refer to Prepare

dilution water

on page 23.

water to a clean 100mL class A volumetric flask.

With a TenSette Pipet, add 1.00 mL of well-mixed 4000NTU formazin stock solution to the 200mL flask.

With a TenSette Pipet, add 5.00 mL of well-mixed 4000NTU formazin stock solution to the 100mL flask.

Dilute to the mark with dilution water. Stopper and mix.

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Table 6 Formazin standard preparation (continued)

Standard Step 1 Step 2 Step 3

1000 NTU Add 50 mL of dilution

4000 NTU Rinse a clean sample

7500 NTU The 7500-NTU

water to a clean 100mL class A volumetric flask.

cell two times with wellmixed 4000-NTU formazin stock solution. Put about 30 mL of 4000-NTU formazin stock solution in the sample cell. No dilution is necessary.

formazin standard is provided in an ampule and is ready for use. Refer to Accessories on page 46. Do not open the ampule or use the contents as dilution stock. The 7500-NTU formazin standard is stable for up to one year.

A class A volumetric pipet may be used in place of a TenSette Pipet.

With a TenSette Pipet, add 25.00 mL of well-mixed 4000NTU formazin stock solution to the 100mL flask.

Dilute to the mark with dilution water. Stopper and mix.

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