Global Water
800-876-1172 • globalw.com
02-002
11/30/09
Global Water
Instrumentation, Inc.
11390 Amalgam Way
Gold River, CA 95670
T: 800-876-1172
Int’l: (916) 638-3429, F: (916) 638-3270
Turbidity Sensor: WQ730
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Global Water
800-876-1172 • globalw.com
Congratulations on your purchase of the Global Water WQ730
Turbidity Sensor. This instrument has been quality tested and
approved for providing accurate and reliable turbidity
measurements. We are confident that you will find this product to
be a valuable asset for your application. Should you require
assistance, our technical staff will be happy to help.
Table of Contents
I. Use and Maintenance • • • • • Page 3
II. Sensor Specifications • • • • • 4
III. Troubleshooting • • • • • • 5
IV. Warranty • • • • • • • 6
V. Appendix A: Turbidity Sensor Calibration • • 7
VI. Appendix B: Turbidity Standard Solutions • • 10
VII. Appendix C: Sensor Measurement Diagram • • 11
VIII. CE Certification • • • • • • 12
Copyright © Global Water Instrumentation, Inc. 2009
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I. Use and Maintenance
a. The WQ730 Turbidity Sensor is a sensitive optical device and should
be handled and used carefully. Avoid hitting or dropping the sensor.
Avoid exposure to shock, vibration, extreme hot or cold temperatures,
or sudden wide temperature changes. Transport the sensor in a safe
and dry enclosure.
b. Normal maintenance requires the sensor to be checked on a regular
basis. Harsh environments can permanently damage the optics of the
sensor if it is left untended for long periods of time.
c. Deposits will develop on the optics over time and should be cleaned
every 2-3 days for best operation. The windows can be cleaned using
lint free cotton swabs and rubbing alcohol. Do not use any abrasive
cleaners on the lenses or permanent damage will occur. Cleaner
water requires cleaning less often, in other applications the sensor
may need to be cleaned once each day.
Global Water
800-876-1172 • globalw.com
d. The calibration of the sensor should be checked every 6 months.
e. Always turn off the power when making circuit connections.
f. Air bubbles on the lenses can greatly affect the readings. When
installing, make sure that any bubbles are clear of the lenses or allow
them dissipate before taking readings.
g. Under no circumstances should the sensor be disassembled. There
are no internal adjustments or user serviceable parts inside. Opening
the housing will permanently damage the seals and can cause serious
damage to the optics. Opening the sensor will void any warrantee.
h. The stainless steel body of the WQ730 Sensor is connected to the
circuit ground. When taking measurements, the body of the sensor
must be in contact with the test solution or noise problems may occur.
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II. Sensor Specifications
a. Specifications.
Outputs: Two, 4-20mA
Ranges: 0-50 NTU (Green Wire)
Accuracy: 1% of full scale
Pressure: 30 psi maximum
Power Requirements: 10-36 VDC
20ma plus sum of both 4-20mA outputs
Warm Up Time: 3 seconds minimum
Operating Temperature: 0°C to +50°C
Storage Temperature: -10°C to +60°C
Dimensions: 1-1/2" diameter x 7-1/2”" long
Weight: 1 lb plus cable
Global Water
800-876-1172 • globalw.com
0-1000 NTU (White Wire)
8 seconds recommended
b. Connections:
Red: 10-36 VDC
Black: Ground
Green: 4-20 mA low range output (50 NTU)
White: 4-20 mA high range output (1000 NTU)
Note: The stainless steel body of the sensor is connected to
the circuit ground and must be in contact with the test
solution.
Warning: Always turn off the power when connecting or disconnecting
the sensor or it could be damaged.
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III. Trouble Shooting
There are no user serviceable parts inside this sensor
Issue: Sensor reading incorrectly
a. Clean the sensor windows using a lint free cotton swab and rubbing
alcohol.
b. Verify there are no air bubbles blocking the lenses.
c. Check the sensor’s calibration, see appendix A.
Other issues
d. Refer to the manual for proper set-up; check all connections and
batteries.
e. Call us for tech support: 800-876-1172 or 916-638-3429 (many
problems can be solved over the phone). Fax: 916-638-3270 or Email:
globalw@globalw.com.
f. In the event that the equipment needs to be returned to the factory for
any reason, please call to obtain a RMA # (Return Material
Authorization). Do not return items without a RMA # displayed on the
outside of the package.
Clean and decontaminate the WQ730 when necessary.
Include a written statement describing the problems.
Send the package with shipping prepaid to Global Water’s factory
address. Insure the shipment, as the warranty does not cover damage
incurred during transit.
g. When calling for tech support, please have as much of the following
information as possible;
1. Model #.
2. Unit serial number.
3. P.O.# the equipment was purchased on.
4. Global Water’s sales number or the invoice number.
5. Repair instructions and/or specific problems relating to the
product.
Global Water
800-876-1172 • globalw.com
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IV. Warranty
a. Global Water Instrumentation, Inc. warrants that its products are free
from defects in material and workmanship under normal use and
service for a period of one year from date of shipment from factory.
Global Water’s obligations under this warranty are limited to, at Global
Water’s option: (I) replacing or (II) repairing; any products determined
to be defective. In no case shall Global Water’s liability exceed the
products original purchase price. This warranty does not apply to any
equipment that has been repaired or altered, except by Global Water
Instrumentation, Inc., or which has been subject to misuse, negligence
or accident.
b. The warranty begins on the date of the product’s invoice.
Global Water
800-876-1172 • globalw.com
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Global Water
800-876-1172 • globalw.com
V. Appendix A: Turbidity Sensor Calibration
Note: The following steps show how to calibrate the WQ730 Turbidity
Sensor using suspended polymer turbidity standards only.
General
a. The Turbidity Sensor is measuring turbidity in liquids by using a 90
degrees scatter nephelometer where a focused beam is directed into
the monitored water. The principle is based on recommendations of
the international guideline ISO
7027. Two detectors receive light from
a source emitting 880 nm infrared light in a pulsed mode. One
detector is placed opposite the source, receiving the transmitted light,
and the other detector is placed at an angle of 90 degrees to the
incident light beam measuring side-scattered light. The detected light
intensity is directly proportional to the turbidity of the water.
b. The following supplies are required:
Stand with rod and clamp
Beakers, 500 or 1000 ml
1000 NTU Turbidity Standard
50 NTU Turbidity Standard
0.0 NTU Turbidity Standard
Distilled Water
Power Supply
Current Meter
Test leads as necessary
The preferred and recommended turbidity standards are suspended
polymer solutions. These are EPA approved, non-toxic, and require
no mixing or stirring. Other types of standards such as Formazin can
also be used, but these require thorough mixing and must be used
with low speed stirring plates during the calibration process.
All the necessary turbidity standard solutions are available from Global
Water, contact the sales department for more information. See
Appendix B.
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Global Water
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Preparation:
a. Set up a test stand with a rod and clamp to hold the sensor. Beakers
will be placed underneath the clamp so the sensor can be inserted into
the liquid.
b. The sensor must have the stainless steel section of the body in contact
with the test solution. Install the sensor so that the end of the sensor
is at least 3 inches from the bottom. If the sensor is too close to the
bottom, infrared light may be reflected from the glass and effect the
measurements.
c. The lenses must be gently cleaned with a cotton swab and isopropyl
alcohol before each calibration step.
d. Fill a large beaker with distilled water. This will be used to rinse
solution from the sensor in between steps.
e. Fill three more beakers with 0.0 NTU Standard, 50 NTU Standard and
1000 NTU Standard. These beakers must be at least 500 ml in size or
the end of the sensor will be too close to the bottom for accurate
calibration. This generally requires solution volumes of at least 500ml.
f. The calibration process should not be done in bright light if possible.
While not generally required, the extra step of covering the outside of
the beakers with a non-transparent material may help to prevent stray
light from the outside affecting the readings.
Note: The sensor is factory calibrated and will provide output currents
of 20mA at the maximum turbidity values; however, some small drift in
this output current can occur over time. These adjustments are done
internally, access to these settings are not available to the user. The
sensors should never be disassembled. The following process
describes how to re-check these output currents. A full recalibration
can only be done by returning the sensor to Global Water.
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Global Water
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Checking Calibration
Step 1) Connect the sensor to the power supply and current meter in
the following way. Attach the black wire to the ground terminal
of the power supply. Attach the white wire to the positive
current input of the meter. Connect the ground terminal of the
power supply to the ground input of the current meter. Check
that the power supply is set between 10 and 30 volts DC.
Attach the red wire to the positive terminal of the power supply.
Warning: Always hook up the red wire last or the sensor may
be damaged.
Step 2) Place the turbidity sensor in the distilled water beaker, rinse
and dry. Clean the lenses with alcohol.
Step 3) Place the sensor in the clamp above the 0.0 NTU standard.
Turn on the power supply and the current meter. Let the
sensor stabilize for several seconds before taking any
measurements. If necessary, use a lint free cotton swab bent
at 90º to remove any air bubbles from underneath the detector
window. Air bubbles will cause large errors in the current
output, especially at low turbidity values.
Step 3) Record the output current of the sensor, Zero
(1000) = _______.
Disconnect the white wire and connect the green wire to the
positive input of the current meter. Let the sensor stabilize.
Record the output current of the sensor, Zero
(50) = _______.
Step 4) Remove the sensor and rinse in distilled water. Dry the sensor
and clean the lenses with alcohol.
Step 5) Place the sensor in the clamp above the 50 NTU solution. If
necessary, use a lint free cotton swab bent at 90º to remove
any air bubbles from underneath the detector window.
Step 6) Record the output current of the sensor, 50NTU = _______.
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Global Water
800-876-1172 • globalw.com
Step 7) Remove the sensor and rinse in distilled water. Dry the sensor
and clean the lenses with alcohol.
Step 8) Disconnect the green wire and connect the white wire to the
positive input of the current meter.
Step 9) Place the sensor in the clamp above the 1000 NTU solution. If
necessary, use a lint free cotton swab bent at 90º to remove
any air bubbles from underneath the detector window.
Step 10) Record the output current of the sensor, 1000NTU = _______.
Step 11) Remove the sensor and rinse in distilled water. Dry the sensor.
VI. Appendix B: Turbidity Standard Solutions
The following turbidity standards are available from Global Water, contact the Sales
Department or Technical Support for more information.
These are EPA approved primary standards that are safe, non-toxic and disposable.
They are easy-to-use with no dilution or re-suspension needed. Their inherent
stability means they do not settle from suspension and require no stirring. The
convenient submicron polymer suspensions are non-toxic primary calibration
standards approved by the US EPA for drinking water analysis for turbidity, and
preferred by the U. S. Geological Survey for turbidity and sediment transport
analysis.
Part Number
Description
02-003 0.0 NTU Turbidity Standard
02-004 50 NTU Turbidity Standard
02-005 100 NTU Turbidity Standard
02-006 1000 NTU Turbidity Standard
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Global Water
800-876-1172 • globalw.com
Appendix C: Sensor Measurement Diagram
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Global Water
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Declaration of CE Conformity
Global Water Instrumentation, Inc.
11390 Amalgam Way
Gold River, CA 95670 USA
FAX: 00 1 916 638 3270
Phone: 00 1 916 638 3429
declares that the Product:
Product Name: Turbidity Sensor and Turbidity Meter
Model Number: WQ730, WQ770
conforms to the following European Council directives:
Low Voltage Directives: 2006/95/EC; Requirements covering all health and
safety risks of electrical equipment operating within
certain voltage ranges.
According to the following standards:
EN61010-1: 2001
Electro-Magnetic Directives: 2004/108/EC; Requirements to prevent electrical
and electronic equipment from generating or being
affected by electromagnetic disturbances.
According to the following standard:
EN 61326-1: 2006
Batteries Directive: 2006/66/EC
proper handling and disposal of batteries and
accumulators.
Global Water hereby certifies that the product stated above conforms to all directives and
standards required for it to bear the CE mark.
Dale Daniel
Engineering Manager
Global Water Instrumentation, Inc.
; Requirements regarding the
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