turbitysesor ts100 manual

7/31/2019 Turbitysesor TS100 Manual

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Turbidity SensorTS100

Edition 3.0

User

Manual


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Greenspan Customer Service+61 7 4660 1888

Technical Support When You Need ItThe correct choice of sensor should be supported by professional advice to ensure long termsuccess in the field. Greenspan Technical Services is dedicated to customer support andprovides assistance in the selection, installation, deployment and commissioning of sensors with afull range of consulting services.

A full technical support and field advice service can be accessed by ringing Customer Service on+61 7 4660 1888 between 8am - 6pm, 5 days a week.

All requests for information will be serviced within 24 hours.

All Greenspan products are designed, developed and manufactured in Australia and can besupplied at short notice.

Warranty Details

Greenspan warrants all new Greenspan products against defects in materials and workmanshipfor 12 months from the date of invoice. During the warranty period, we will repair or, at ouroption, replace at no charge a product that proves to be defective provided that it is returned,shipping prepaid, to Greenspan Technology Pty Ltd.

Greenspans liability and obligations in connection with any defects in materials andworkmanship are expressly limited to repair or replacement, and the sole and exclusive remedy inthe event of such defects shall be repair or replacement. Greenspans obligations under thiswarranty are conditional upon it receiving prompt written notice of claimed defects within thewarranty period and its obligations are expressly limited to repair or replacement.

This warranty does not apply to products or parts thereof which have been altered or repairedoutside of the Greenspan factory or other authorised service centre, or products damaged by

improper installation or application, or subjected to misuse, abuse neglect or accident. Thiswarranty also excludes items such as reference electrodes and Dissolved Oxygen membranes thatmay degrade during normal use.

Greenspan Technology Pty Ltd will not be liable for any incidental or consequential damage orexpense incurred by the user due to partial or incomplete inoperability of its products for anyreason whatsoever or due to inaccurate information generated by its products.

All Warranty service will be completed as soon possible. If delays are unavoidable customers willbe contacted immediately.

The sensors should not be dismantled unless under instruction from Greenspan. Incorrecthandling will void the warranty.


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Contents

1. INTRODUCTION

Overview 1Theory of Turbidity 1

Turbidity and Suspended Solids 2

Stream Water Turbidity 2

2. TURBIDITY MEASUREMENT

Formazin Definition 3

Calibration Considerations 3

3. THE HARDWARE

Overview 4

Sensor Design 5

4. INSTALLATION

Connection 6

General Methods of Installation 7

Typical Locations 7

Option 1: Non Turbulent Conditions 8

Option 2: High Turbulent Conditions 8

Other Considerations 8

Turbidity Deployment 9

5. CLEANING AND MAINTENANCE 11

6. QUICK CALIBRATION CHECK METHODChecking Calibration Using Calibration CupsTR100 12

Calibration of Turbidity Cups 13

7. FORMAZIN CALIBRATION METHOD

Test Setup 15

Formazin Standards from Ref Stock Suspension 16

Preparation of Formazin Standard 16Materials 17

Procedure 17Checking Standard Against a Hach Turbidimeter (Optional) 17Calibration Method 18

Preliminary Setup 18

Zero Checking 18

Full Scale Checking 18

8. REFERENCES 20

9. SPECIFICATION and CERTIFICATE of CONFORMANCE 21


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10. APPENDIX

Errors in Measurement 23

Bench Testing 23

Noise 23Offsets 23

Bubbles 23

Algae 23

Colour 23

Turbidity Sensor Cleaning Pump TP100 24Function 24

Installation 24

TP100 Specification 26


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INTRODUCTION 1

Overview

The Greenspan TS100 Turbidity Sensor utilises a high gain infrared optical

system to detect the back-scatter intensity of suspended particles

by transmitting a beam of 880nm wavelength and measuring the received

intensity of reflected light.

Advanced digital filtering techniques are used to eliminate ambient light and

stray signals from the measurement of data.

A current loop output of 4 - 20mA is provided on the TS100 Series Sensor.

The external optical surface is coated with a special polymer which resistsfouling from algae growth. It does not eliminate the problem but increases the

time between cleaning.

The sensor is packaged in a 316-grade stainless steel or Acetal co-polymer tube,

with

O ring sealed Acetal co-polymer end fittings. The design is rugged and well

proven and can withstand the harsh conditions found in any field environment

Theory of Turbidity

Turbidity is the term used to describe the reduction in water clarity or

"cloudiness" as perceived by the human eye caused by the scattering of light due

to particulate matter suspended in solution. The greater the turbidity, the more

cloudy the water. Increases in turbidity reduce the transmission of light.

Because most aquatic plant growth and marine organisms depend upon natural

light radiation for survival, and light penetration in water is dependent on the

clarity of the water, the measure of turbidity is useful for assessment of water

quality.

Due to the effects of erosion within catchment areas, tiny particles of clays, silts

or small organic particles are washed into water bodies. Industrial wastes and

sewerage can also contribute particles.

Oceanographers, Engineers and Geomorphologists who are studying the

movement of suspended sediments find turbidity a useful factor in defining

relative changes in sedimentation between sites.

The rate at which the water is moving limits the amount of suspended solids it

can carry.

The inherent simplicity of turbidity measurement allows for the continuous in-

situ gathering of data. This is very useful when monitoring rapidly varying

turbidity conditions, and it is the main advantage compared with the laboratory

sample method.

UM-010-0006-TS GREENSPAN TECHNOLOGY 1


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Turbidity and Suspended Solids

Suspended particles in the water are the principle source of turbidity.

Assuming that the turbidimeter has been calibrated to give a linear response to

standards (such as Formazin) varying only in concentration, the relationship

between suspended solids concentration and turbidity depends mostly onparticle size, composition and particle concentration. Even in streams that

transport sand during storm event runoff, strong relationships between

suspended solids and turbidity have been observed. In such cases, the

turbidimeter is responding less to the coarse fraction, but because the

concentration of the fine fraction (the main source of turbidity) increases

proportionately with the concentration of the coarse fraction, the turbidity is an

adequate index of the total suspended load. The relationship between turbidity

and total suspended solids in this case is non-linear. A linear relationship

should only be expected in cases where the particle size, shape and composition

do not vary through time. (Ref: Gippel, AJSWC, 1994)

Stream Water TurbidityIf turbidity is established as an index of suspended solids, then considerable

savings will result from reduced labour costs for field sample collection and

laboratory analysis. Stream water turbidity is likely to reflect catchment

condition, so a catchment-wide network of continuously recording instruments

could be used in a surveillance role to identify areas of landslips, stream bank

disturbance, or inappropriate land use practices. (Ref: Gippel, AJSWC, 1994)



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TURBIDITY MEASUREMENT 2

Greenspan turbidity sensors are of the back scattering type and respond to theaverage volume scattering of particulate matter over a defined angular range.

Both particle size and concentration affect readings.

Output is calibrated in terms of NTU (Nephelometric Turbidity Units).

The instrument does not measure in absolute terms but relative to a Formazin

standard, (see below). A comparison is made of the intensity of scattered light by

a sample and the intensity of scattered light by a standard reference.

Formazin Definition

Formazin is a white insoluble polymer formed by the condensation reaction

between hydrazine sulphate and hexamethylenetetramine, (Ref: Gippel,

AJSWC, Nov 1994). It forms a mono disperse dispersion of approximately 2.5

m geometric mean volume particles (Gippel, 1988a ).

Formazin reference solution is supplied as 4000 NTU primary standard and is

diluted with high quality distilled water to lesser concentrations for calibration.

Secondary standards of Formazin are available from various manufacturer's,

often as a gel suspension or sealed latex suspension, and are stable for up to 1

year when properly stored.

Secondary standards provided with reference test equipment are usually used tostandardise the instrument before each reading. (Ref: Standard Methods, 1995)

Calibration ConsiderationsVarious Turbidity units have been used to reference turbidity measurement.

(JTU, NTU, FTU, EBC, CNU, FAU, FNU) they are not all equivalent and they

should not be confused with mass concentration.

ISO 7027 recommends the adoption of FNU (Formazin Nephelometric Units)

and FAU (Formazin Attenuation Units), (Ref: Gippel, AJSWC, Nov 1994)

The most recognised and widely adopted reference standard is Formazin,

one FNU is equivalent to one NTU, (Nephelometric Turbidity Units) so NTU

has been adopted by Greenspan for turbidity calibration.

Derived standards are only stable for a few days and therefore have to be

prepared each time the instrument is checked.

Proper laboratory handling is essential as Formazin is a suspected

carcinogen. A simplified method not requiring Formazin is provided

in this manual using Greenspan Turbidity Reference Cups TR100.



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THE HARDWARE 3Overview

The TS100 turbidity sensors utilise an infra-red optical system to measure

scattered reflected radiation across an angle of 30. Infra-red transmission is

used because light of this frequency is heavily attenuated in water, therefore the

beam penetration is reduced to practical limits and infra-red interference from

sunlight is also reduced with depth.

The sensor is constructed of environmentally inert materials, 316 stainless steel

and Delrin plastic. The form is cylindrical with the following dimensions:

Transmission LEDs

B. Reception Photodiode30

C. Infra-red Lens

Optical Head

A.A

B

C

C

Side ViewFront View

275

*44.4

25

TS100 Turbidity Sensor

All dimensions in mm

*47mm max for Delrin

Alignment Mark

A

Alignment Mark

Figure 1. Overview

The standard package includes:

1 316 stainless steel body- Delrin optional

2 Delrin sensor head

3 Delrin cable gland.

4 Optical filter lens



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Sensor Design

A digital synchronous detector system is used to eliminate common mode carrier

signals and effectively provide a narrow band limited signal path. This method

ensures minimal interference from stray light frequencies (ambient light) and

maximum reception of signal strength.

The optical system is embedded in epoxy compound for stability and

waterproofing and ensures an ambient light proof, mechanically robust

mounting.

Quality electronic components are used throughout for reliable long term

operation and boards can be easily accessed and serviced.



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INSTALLATION 4ConnectionThe TS100 is designed as a three wire 4-20mA current system and is nominally

powered by 12V DC. The sensor is normally supplied with open ended bare

wires for connection to power and external data logger.

The following diagram illustrates the wiring arrangement for the TS100.

50 ohm

o

o

9 27VDC,

typically +12V

Ground

Blue

Red

Green

Load or m A meter

Output

Power

TS

Figure 2. Connection

The input voltage range is 9-27V and it should be noted that as the quiescent

current is 80mA and at full scale the output current is 20mA the total is

1000mA. The resistance of the cable is 9 ohms per 100 metres, therefore a 25m

length of cable will give a voltage drop of :

100mA x 9 x 25 = 0.225V for the active red wire

100

This is duplicated for the return green wire:

0.225 + 0.225 = 0.450V

Therefore, approximately 0.45 volts less is developed across the sensor. That is, a

12V supply with 25m of cable will effectively provide 11.55V at the sensor.

The sensors are protected against reverse voltage occurrences and against

voltages of 2KV such as may occur during lightning storms. However, if using in

areas prone to lightning activity it is recommended that lightning arresters be

fitted to all input cables.



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General Methods of InstallationThe Greenspan Range of Water Quality Sensors can be installed into a variety

of applications including:

Rivers, Lakes and streams Bore Hole and groundwater wells

Tanks and Reservoirs

Wet Wells for Water and Sewer Systems

In all field applications, mechanical, electrical and physical protection of the

Sensor, cabling and associated fittings must be provided.

Consideration needs to be given for the protection against vandalism, animal

damage, theft and extreme weather conditions.

There are a many ways of positioning sensors in the field in order to ensure the

continuous collection of data and the safety of the device.

Some methods commonly in use are:

1. Floating Buoy for use at sea, can be installed with telemetry/cell phone

communications.

2. Suspended Sensor attached to a guide wire and winch board, which is

useful for profiling applications.

3. Fly wire across stream/river, sensor tethered to fly wire and fully

immersed.

4. Installed in PVC conduit with sensor emerging from the immersed end.

5. Sealed waterproof, self contained vessel including batteries and

continuous logging equipment. Excellent for concealment.

6. Strapped to pylon or post in areas that become submersed, cabled to

bank. Ensuring 100mm clearance from post.

7. Hand operation for spot readings.

Typical Locations

1. Edge of river/stream/lake embankment.

2. Side of boat/vessel.

3. Mounted within a stilling well off stream from main flow.

4. Mounted within drainage channels/pipes.

5. Suspended from dam walls.

6. Sensor anchored to bed of lake/stream.



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Field Installation must ensure:

The sensor is anchored or held in position or located so it is not subject to

any movement during normal operations.

Sensor is protected from direct sunlight to avoid high temperature

fluctuations Sensor is protected against high turbulence and possible debris loading

during flow events

Option 1: Non Turbulent Conditions

Where there is no possibility of the sensor being affected by turbulence it can be

suspended into the water body using a stainless steel hanger cable. For

example where the sensor is installed into a large water storage tank. The

sensor will hang vertically into the tank and not be subject to movement from

water movements. The stainless steel wire prevents loading of the sensor cable.In Sewer Wet Well and Water Tank applications where high turbulence and

debris loading may affect the sensor, the following minimum installation

standards must be followed:

Option 2: High Turbulent Conditions

Where turbulence and water movement will act on the sensor it is recommended

to mount the sensor in a stilling well or mounting cradle attached to the side of

the well. This could simply be a length of PVC pipe bolted to the well wall in

which the sensor is located or could be an extension pole with a sensor cradle at

the lower end. Potential ragging and debris build up on the sensor & cableshould be overcome by extending the stilling well to above the high water level

or by cable tying the sensor cable up the cradle mounting arm. The movement

of the sensor must be eliminated such that the sensor is not subject to twisting

motion from swirling water during pumping, or from sideways movement due to

ragging of the sensor.

In all sewer wet well applications regardless of the mounting system used it is

recommended to also utilise a stainless steel hanger cable* to prevent loading

the sensor cable during installation, removal and maintenance. The stainless

steel wire must be securely connected to the sensor using the hanger hook and

the sensor cable should be cable tied at regular intervals up the stainless wire.

An outer sheath of hose or tubing can be fitted over both cables to reduce

ragging and debris build up on the cables. At the top of the well the stainlesswire can be attached to a bolt or mounting point.

*Note, the stainless steel suspension, hanger cable can be provided by

Greenspan. (Part No 7SK-100)

Warning:Under no circumstances must the sensor be installed such that it can

collide with the sides of the well, or other solid objects within the well.

Sensor installation under these circumstances will lead to sensor

damage that will not be covered under our normal warranty

conditions. In these cases the sensor must be mounted into a cradle or

stilling well as per Option 2.



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Other Considerations

Environmental compatibility should be checked before using the sensors and

advice sought from Greenspan if any doubt exists. The 316 stainless body can be

used in a majority of situations but care should be taken against possible

corrosion in high Chloride, Sulphate or Ferric solutions.The body should always be totally immersed under the water to ensure that the

sensor is at water temperature and to also avoid any possible anodic/cathodic

action taking place on the stainless body at the water-air interface. At some

sites it has also been noticed that clamps used to support the sensor made of a

dissimilar metal to the 316 stainless body can cause spot corrosion due to

electrolysis.

Turbidity DeploymentWhen mounting turbidity sensors in water ensure a minimum clearance around

the optical head of 50 mm and approximately 250 mm forward to reducereflection from non-data surfaces. Note that reflection errors increase the closer

the transmit LED is to a reflective surface. Therefore in tight installations it is

preferable to rotate the sensor so that the Alignment Mark is furthest from the

reflective surface. The Alignment Mark on the head is positioned adjacent to the

transmit LEDs, see Diagram 1, page 4.

When installing in very shallow water immerse to at least 250-300 mm

minimum to prevent infra-red radiation from natural sunlight affecting

readings. It is preferable to point the sensor face down or at an angle.

Alternatively, process the resultant data file so that only data recorded in non

daylight periods is accepted.

When installing directly into a flowing medium, angle the sensor head such that

it is inclined at an angle of at least 45 to the horizontal and such that the

sensor lens is facing downstream. This will minimise the damage to the lens as

a result of impact from travelling particulate matter.

If using the model TP100 lens cleaning pump it is important to ensure pump is

primed prior to positioning sensor at depth. This can be achieved at just below

surface level by manually triggering the pulse line or driving it from a logger,

and checking for correct pump operation and then lowering sensor to the desired

depth.

To manually check the pump operation, press the test button located inside theTimer Controller unit or briefly connect the trigger wire from the pump to

ground, (negative pulse) or to +ve supply (positive pulse).

When the cleaning pump is activated the force of the water creates artificial

turbulence and if left untethered, can cause slight displacement of sensor

position. It is preferable that the logged readings do not coincide with the pump

activation cycle, which may lead to errors. To minimise this, do not start the

recording logger at the same time as the pump timer and tether the sensor.



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Most sediment transport occurs during storm events and flood conditions.

Protection from floating debris damage is an important consideration along with

adequate tethering of sensors.



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CLEANING AND MAINTENANCE 5

Protection of the lens surface is vital to maintain the accuracy of the calibration.

The prevention of algal growth and marine encrustations on the lens (and body

in general) is desirable. Both the polymer and Turbidity Cleaning Pump assist

in this process. Please refer to Appendix for further information on the Lens

Cleaning Pump.

The lens may be cleaned using warm soapy water, a soft cloth and a gentle

rubbing action.

WARNING

DO NOT USE METHYLATED SPIRITS or ALCOHOL on LENSSURFACE

If scratches are evident on the lens which cannot be removed through polishing

please contact Greenspan. It may be possible to recalibrate the offset to

eliminate the effects of the damage. Alternatively, the lens/head can be replaced

and the unit re-calibrated.

Note that regular cleaning of the lens will, in time, remove the polymer coating

applied during manufacture. Please contact Greenspan if you wish new coatings

to be applied.



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QUICK CALIBRATION METHOD 6

There are two methods in this manual for checking the calibration. The firstuses TR100 calibration cups and the second uses Formazin reference solution.

CHECKING CALIBRATION USING CALIBRATION CUPS TR100

To enable quick and easy checking of sensor calibration Greenspan can supply

calibration cups (TR100) matched to the particular sensor. There are two cups,

one for zero and one for full scale. These are simply slid over the sensor head

and the reading obtained should match the recorded reading taken when the

sensor was newly calibrated. Any difference will indicate that calibration has

changed.

NOTE: An individual cup will not measure the same turbidity value on

different sensors. The cup must be calibrated and matched to an

individual sensor prior to use. See Calibration of Turbidity Cups.

Method

1. Gently remove any debris which may have accumulated on the sensorhead with a moist soft cloth, avoid scratching the turbidity lens. Dry the

lens.

2. Remove the protective cap on the high and low turbidity calibration cupsand pour 2.5ml or 1/2 teaspoon of silicone oil into each and allow them to

form a level, bubble free layer over the calibration suspension in the base

of the cups.

3. Slide the low value turbidity calibration cup over the sensor head until itreaches the bottom, (some silicone oil may overflow). Rotate the cup,

while keeping firm contact on the bottom, to line up the alignment mark

on the cup with the mark on the sensor head.

4. Once the cup and sensor are in place and aligned, remove your handsfrom the sensor and allow the assembly to stand in a vertical position

(with the cup on the bottom) while taking the reading.

NOTE: Air bubbles trapped between the sensor lens and the

calibration suspension will cause high and erratic readings. Be

sure to use an adequate amount of silicone oil to prevent this

from occurring and ensure no air bubbles are present prior to

installing the cup. It is also important not to break contact with

the interface prior to reading the calibration point.

5. Connect the sensor output to a milliammeter. Check that the reading is

equivalent to the recorded value assigned to that sensor for that

calibrator cup.

6. Repeat steps 3-5 for the high calibration cup.

7. If the output reading is not within 3% of expected reading (value markedon Reference Table for that sensor) the sensor is out of calibration.



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8. Remove the cup and wipe the sensor head clean of oil with a soft cloth.

9. If re-calibration is necessary, contact a Greenspan authorised agent for

re-calibration.

CALIBRATION OF TURBIDITY CUPS

Function

Each cup and sensor must be matched prior to use in checking. If this was not

done at the factory, then the matching can be performed by the customer on the

bench using the following procedure. Note that this assumes that the sensor has

been accurately calibrated recently. Once matched the pair should remain

stable indefinitely.

Method

1. Gently remove any debris which may have accumulated on the sensor

head with a moist soft cloth, avoid scratching the turbidity lens. Dry the

lens.

2. Ensure that the sensor has been accurately calibrated, if not, return the

unit to a Greenspan authorised agent for re-calibration.

3. Engrave a permanent alignment mark laterally, anywhere along the

sensor head. Be careful not to scratch the sensor lens.

Alignment Mark

4. Clean and dry the sensor head with a soft cloth.

5. Remove the protective cap on the high and low turbidity calibration cups

and pour 2.5mL or teaspoon of silicone oil into each and allow them to

form a level, bubble free layer over the calibration suspension in the base

of the cups.

6. Slide the low value turbidity calibration cup over the sensor head until it

reaches the bottom, (some silicone oil may overflow). Rotate the cup while

keeping firm contact on the bottom, to line up the alignment mark on the

cup with the mark on the sensor head.7. Once the cup and sensor are in place and aligned, remove your hands from

the sensor and allow the assembly to stand in a vertical position (with the

cup on the bottom) while taking the reading.

NOTE: Air bubbles trapped between the sensor lens and the

calibration suspension will cause high and erratic readings. Be

sure to use an adequate amount of silicone oil to prevent this

from occurring and ensure no air bubbles are present prior to

installing the cup. is also important not to break contact with the

interface prior to reading the calibration point.

8. With the sensor output connected to a milliammeter. Record the reading ofthe sensor onto the Turbidity Reference Table in the calibrator kit, using a



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waterproof pen. Also, record the serial numbers of the turbidity sensor and

turbidity cup. These may be changed or removed later with methylated

spirits if the calibration is redone.

9. Repeat steps 6-8 for the full scale calibrator cup.

10. Remove the cup and wipe the sensor head clean of oil with a soft cloth.

Note that the same cup may be used on different sensors of the same range with

correspondingly different readings being obtained. Each reading is valid for that

particular sensor and all are recorded on the Turbidity Reference Table provided

in the TR100 kit.



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FORMAZIN CALIBRATION METHOD 7

Test Setup

A test setup such as the one described below is recommended for both zero and

full scale calibration checking. It is recommended the solution is kept moving

with a magnetic stirrer mounted underneath the full scale vessel to minimise

contact with solution.

The full scale calibration suspension using Formazin is prepared according to

Table 1. Allow a few minutes settling time for the Formazin to be evenly

distributed through the test vessel. See figure 3.

Magnetic stirrer mounted

underneath F/S vessel.

Clear Filtered WaterCalibration Suspension

5L Test Vessel F/S Set 20L Test Vessel Zero Set

oo- +

mA

Sensor Power Supply

Sensor

+12V, RED

Output, BLUE

Ground, GREEN

Can use magnetic stirrer for

minmum solution contact

Figure 3. Calibration Checking Setup TS100 Turbidity sensors

It must be considered that the validity of diluted Formazin Solution is time

dependant. For example, both "Standard Methods for Examination of Water and

Waste Water" and the US E.P.A recommend that 400 NTU suspension not be

used for longer than 30 days, and a 40 NTU value suspension no longer than 7

days if affected by light and temperature.

A sealable container of 5 litre capacity may be used for storage of Formazin and

calibration. The sensor should be held in the centre by means of a clamping

arrangement to eliminate side wall reflections. Ensure that the container used

for Formazin Calibration is a minimum size of 5 litres and has a diameter at

least 8 inches.

The zero solution should preferably be in a 20 litre container painted matt blackinside and well filtered water must be used.



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Materials

Hydrazine Sulphate (reagent grade) 5.000g

Hexamethylenetetramine (reagent grade) 50.00g

Procedure1. Set oven to 25C.

2. Transfer hydrazine sulphate to a 5000ml volumetric flask and add de-

ionised water to almost the mark. Stir to dissolve, then fill to the mark

with de-ionised water.

3. Transfer hexamethylenetetramine to a 5000ml volumetric flask and add

de-ionised water to almost the mark. Stir to dissolve, then fill to the mark

with deionised water.

4. Place both flasks in the 25C oven and allow to reach temperature.

5. Transfer all the contents of the hydrazine sulphate flask to a 10 litre

container equipped for magnetic stirring.

6. Slowly transfer all the contents of the hexamethylenetetramine flask to the

10 litre flask while stirring continuously.

7. Stop stirring when both solutions are mixed. Seal the 10 litre container

and allow to stand at 25C for 24 hours.

Checking Standard Against a Hach Turbidimeter (Optional)Mix the Formazin standard to be checked by making sure the lid is on tight and

then tumbling the canister several times (10 sec). Fill a clean Hach turbidity cell

with the standard, wipe the walls with silicone oil, and place it in a Hach 43900

Ratio/XR Turbidimeter. Record the readings when it is stable, (15 sec). Write

the value and date on the canister label. If the value has changed by more than

10% from its value at preparation, then prepare a new standard. Use the

standard within three days of checking.



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CALIBRATION METHOD

Preliminary Setup

Connect the sensor to +12V (red wire) and ground (green wire) and connect

current meter, (+), between blue and power supply common (-) green. See fig. 3.

Zero Checking

1. With power applied to the unit, place the sensor in the zero NTU bath at a

sufficient depth to cover the optical head and let the temperature

equilibrate for approximately 1/2 hour.

NOTE: Air bubbles trapped between the sensor lens and solution

will cause high and erratic readings. To reduce this, immerse the

sensor at an angle and if necessary gently rotate the sensor until

all bubbles surface.

2. If output reading is not within 3% of 4.00mA, contact a Greenspan

authorised agent for re-calibration.

3. After checking the zero value, rinse the sensor in clean water, wiping with

a tissue to remove excess water.

4. If zero reading is correct go to next section.

Full Scale Checking

1. Apply power to the magnetic stirrer and allow at least 15 min to give

circulation of the suspension.

Great care is necessary handling Formazin as it is a suspected

carcinogen.

2. Place the sensor into the test vessel prepared with a full scale NTU

Formazin solution. If there is any doubt about the accuracy of the solution

it is recommended it is checked on a Hach Turbidimeter. Ensure sensor is

in bath at a sufficient depth to cover the optical head. Ensure there areno trapped air bubbles by tilting the sensor slightly whenimmersing.

3. The expected reading can be calculated as follows:

Output (mA) = ( ( b x 16 ) + 4 )mA

a

where:

a = Full scale range of instrument (NTU)

b = Full Scale reading of Formazin Standard as measured by

laboratory instrument such as Hach Turbidimeter

for example:



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If sensor is a 500 NTU range and the Standard is 490 NTU

output (mA) = ( ( 490 x 16 ) + 4 ) mA = 19.68mA

500

4. If the output reading is not within 3% of the calculated value then re-

calibration is required. Contact a Greenspan authorised agent for re-

calibration.

5. After checking the full-scale value, rinse the sensor in clean water, wiping

with a tissue to remove any suspension material.



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REFERENCES 8

GIPPEL, C.J., 1989. The Use of Turbidity Instruments to Measure StreamWater Suspended Sediment Concentration. pp 12, Ch 2.

GIPPEL, C.J., 1988. Comparison of fine particle size determination by Coulter

Counter Model TA11 and Horiba CAPA-300. pp 11, Ch2.

GIPPEL, C.J., 1994. Monitoring Turbidity Of Stream Water, Australian Journal

of Soil and Water Conservation Vol. 7, No 4, pp 41.

Waterwatch Queensland Technical Manual., State of Qld, Department of

Primary Industries 1994. pp. 16.

STANDARD Methods for the Examination of Water and Wastewater, 19th

Edition 1995, 2130 Turbidity, 2-8 to 2-11



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SPECIFICATION and CERTIFICATE of CONFORMANCE 9

Specification Model TS100

Standard Ranges available 0-100NTU

0-250NTU

0-500NTU

0-1000NTU

Other ranges available on request.

-------------------------------------------------------------------------------------------------------------

Linearity 0-50NTU 3.0%

0-100NTU 3.5% or 3.0%*

0-250NTU 4.0% or 3.0%*

0-500NTU 9.0% or 3.0%*0-1000NTU 11.0% or 3.0%*

0-2000NTU 12.0% or 3.0%*

*NOTE: A linearity performance oftypically 3% for all ranges may be achieved by the use of

algorithmic data correction. Contact Greenspan Technology for further information .

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Accuracy 3% FS (with algorithm)

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Supply Voltage 9-27VDC

Reverse polarity protected

Surge protected to 2kV

--------------------------------------------------------------------------------------------------------------Quiescent Current 80mA

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Warm up time to stable reading 2 Seconds

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Output 4-20mA, 0-1V, 0-2.5V

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Dimensions length 275mm,

44.5mm OD Stainless Steel

47mm OD Acetal co-polymer

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Wetted Materials 316 Stainless Steel,Acetal co-polymer

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Weight (potted) 735g, 316 Stainless Steel

605g, Acetal co-polymer

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TURBIDITY

SENSOR

22 Palmerin Street, Warwick 4370 Qld Australia.

Tel: 0746 601888 Fax: 0746 601800

CERTIFICATE of CONFORMANCE

Model No TS100

Customer:

Ref:

ProductDetail Serial No. 010410

Range 0 - 500 NTU

Output FS 20.00mA

Zero 4.00mA

Accuracy +/- 3 % of FS(with algorithm)

Linearity See User Manual

Cable Length 60 metres

Supply Voltage 9 - 27 VDC

Supply Current 80 mA

Connection: +ve Red

gnd Green

o/p Blue

Connection Code BW3

For further connection detail please refer toConnector Chart supplied.

User

Notes 1. The sensor is protected against reverse polarity.

2. Do not attempt to dismantle the sensor as it will void the warranty. Contact your agentfor technical advice.

2. The lens cover has been coated with an anti-fouling polymer to prevent marine growthaffecting accuracy.

3. The calibration instrument utilises a flow-through cell within a Hach Ratio Turbidimeterreferenced against Formazin solutions.

Inspected By ............ / /



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APPENDIX 10

ERRORS IN MEASUREMENT

Error variations can occur in data due to a number of factors:

1. Bench Testing The sensor is designed for intermittent sampling while fully

immersed. Therefore any readings taken in air are not valid.

They may only be used to indicate functional operation.

2. Noise Environmental transients greater than the mean signal

contribute to the background noise level. Also signal drift not

associated with the actual flow conditions is considered to be

noise. These can be caused by large floating debris, aquaticlife (fish) and installation lines obscuring the optical path

briefly.

3. Offsets Reflections from nearby surfaces of conduit, sea floor and

river bed can offset readings, allow a clearance of at least

250mm forward and 50mm to each side of the optical system.

4. Bubbles Trapped air bubbles on the filter lens. Can be removed by

tilting or stirring the sensor, positioning away from turbid

water inlets and using lens cleaning pumps.

5. Algae Algal growth will cause significant errors in as little as 35

hours in extreme conditions, if allowed to accumulate on the

lens. Regular cleaning and maintenance is essential, how

often this is required is dependent on the severity of the

micro-organism activity in the particular environment. A trial

period should be allowed initially to determine the cleaning

regime.

6. Colour Stream water in forested Australian catchments is often

coloured with Gilven. This component is leached from the

leaves of trees, particularly in areas dominated by barked

Eucalyptus. Gilven reduces Nephelometric turbidity by up to10%. Light sources with a wavelength of greater than 600 nm

are insensitive to Gilven such as the Greenspan

turbidimeters. (Ref Gippel 1989a).



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TURBIDITY SENSOR CLEANING PUMP TP100

FunctionTo maintain the optical cleanliness of the Turbidity Sensor by preventing

fouling due to algal growth. A high pressure jet of filtered water is periodically

forced across the lens dislodging any buildup of algae. When used in conjunction

with the non stick polymer an efficient method of cleaning is produced. This

system is particularly suitable for long term unattended data collection

situations.

InstallationThe unit conveniently clamps onto the TS100 sensor for easy installation and

removal. The power cable is strapped to the sensor cable and brought to the

surface for connection to the Timer Controller and battery.

The Controller unit can be programmed for various Intervals and turn-on

Durations by settings within the box. Please refer to the table below for settings

available.

Table 2.

Switch Setting Interval (Hours) Duration (Seconds)

0 1 2

1 2 5

2 3 10

3 6 154 12 30

5 24 60

6 48 120

7 72 240

The duration chosen can easily be tested by momentarily pressing the TEST

button located internally, this will activate the pump motor.

A positive or negative going 5-12V input trigger from an external logger or

Smart Sensor can also be fed to the Controller where a relay switched and timed

pulse of power is generated. Smartcom software can be programmed to pulse thepump at regular intervals. Background Sampling can be selected in Sampler

mode and is independant of the normal logged record interval. If the Smart

Sensor is used as the trigger source, a negative going pulse is output from the

sensor - please refer to the Smart Sensor user manual for connections.

Greenspan recommends the customer establishes a cleaning regime dependant

on environmental site conditions bearing in mind that the more often the pump

is turned on the shorter the lifetime of the battery. An initial interval of 3 hours

and a duration of 10 seconds is suggested as a starting point.



29/30

If possible, it is preferable to test the assembled pump mounted on the sensor by

immersing near the surface prior to deployment at depth to verify operation and

pump priming.

The clamp can be removed from the sensor by undoing the two Allen key bolts

and sliding the assembly off the turbidity head. When repositioning, ensure thatthe dispersal nozzle vent hole is forward of the optical head lens to maintain the

water jet across the lens face.

The pump filter cap is a push fit onto the motor body and is easily removed for

cleaning.

Pump Motor

FilterInlet

Powe r Cable toCont rol Box

Optical Head

Disp ersal

Nozzle

Turbid ity Sensor

TP100Pump Clam p

Figure 4. Pump Installation

Note that the pump clamp has been designed to fit the optical head to allow for

the differences in outside diameter of the sensor tube depending on whether

Delrin body or stainless steel is used. When assembling the pump to the optical

head, push the sensor all the way to the end stop and tighten the locating

screws with a 2mm Allen key.

The power supplied to the Timer Control unit is internally regulated to

maintain timing consistency. The pump can be submerged to depths of up to

50m, with cable lengths up to 70m maximum. It is suggested cable ties are usedto attach the pump cable to the sensor cable.

It is recommended that a separate battery be used for the pump due to the

greater power required and the switching transients that may be present. It is

necessary however, to ensure a common ground between the pump power supply

and the sensor supply.



30/30

SPECIFICATION TP100

Specification Model TP100

Connections Power +ve Red wire

Power Ground Black wire

Trigger Input User option, connections

internal

Supply line is protected internally with an

automatically reset polyfuse.

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Dimensions 115 x 90 x 55 (mm)--------------------------------------------------------------------------------------------------------------

Power requirements 12 - 15VDC, typically 3 Amps. Supplies power to

both Timer Control unit and pump motor

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Cable Maximum length 70 metres, with 12VDC supply

--------------------------------------------------------------------------------------------------------------

Supplied with 1 x Pump cable

1 x Pump filter cap

1 x Timer Control unit, providing a variable timed

pulse to the pump motor as well as an external

trigger pulse capability.

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turbitysesor ts100 manual

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