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Instruction Manual
HI 95761C
Total Chlorine Meter
for the analysis of
trace Total Chlorine concentrations
www.hannainst.com
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MAN95761R2 05/06
www.hannainst.com
This Instrument is in
Compliance with the CE Directives
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Dear Customer,
Thank you for choosing a Hanna product. This manual will provide you with the necessary
information for the correct use of the instrument. Please read it carefully before using the meter. If
you need additional technical information, do not hesitate to e-mail us at tech@hannainst.com.
This instrument is in compliance with
directives.
TABLE OF CONTENTS
PRELIMINARY EXAMINATION............................................................................................... 3
GENERAL DESCRIPTION ...................................................................................................... 4
ABBREVIATIONS ................................................................................................................ 4
SPECIFICATIONS ................................................................................................................ 5
PRECISION AND ACCURACY ................................................................................................. 5
PRINCIPLE OF OPERATION .................................................................................................. 6
FUNCTIONAL DESCRIPTION .................................................................................................7
GUIDE TO DISPLAY CODES .................................................................................................. 9
GENERAL TIPS FOR AN ACCURATE MEASUREMENT ............................................................. 11
MEASUREMENT PROCEDURE............................................................................................. 13
VALIDATION PROCEDURE .................................................................................................. 15
CALIBRATION PROCEDURE ................................................................................................16
BATTERY REPLACEMENT.................................................................................................... 18
ACCESSORIES ................................................................................................................. 18
CE DECLARATION OF CONFORMITY .................................................................................... 19
WARRANTY ...................................................................................................................... 19
CE DECLARATION OF CONFORMITY
Recommendations for Users
Before using these products, make sure that they are
entirely suitable for your specific application and for
the environment in which they are used.
Operation of these instruments may cause
unacceptable interferences to other electronic
equipments, this requiring the operator to take all
necessary steps to correct interferences.
Any variation introduced by the user to the supplied
equipment may degrade the instruments' EMC
performance.
To avoid damages or burns, do not put the instrument
in microwave oven. For yours and the instrument
safety do not use or store the instrument in hazardous
environments.
WARRANTY
HI 95761 is warranted for two years against defects in workmanship and materials when used for
its intended purpose and maintained according to the instructions.
This warranty is limited to repair or replacement free of charge.
Damages due to accident, misuse, tampering or lack of prescribed maintenance are not covered.
If service is required, contact your dealer. If under warranty, report the model number, date of
purchase, serial number and the nature of the failure. If the repair is not covered by the warranty,
you will be notified of the charges incurred.
If the instrument is to be returned to Hanna Instruments, first obtain a Returned Goods Authorization
Number from the Customer Service Department and then send it with shipment costs prepaid.
When shipping any instrument, make sure it is properly packaged for complete protection.
To validate your warranty, fill out and return the enclosed warranty card within 14 days from the
date of purchase.
All rights are reserved. Reproduction in whole or in part is prohibited without the written consent
of the copyright owner, Hanna Instruments Inc., Woonsocket, Rhode Island, 02895 , USA.
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HANNA instruments® reserves the right to modify the design, construction and appearance of
its products without advance notice.
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E
FACTORY CALIBRATION RESET
It is possible to restore factory calibration:
• Enter the calibration mode by holding CAL CHECK
for three seconds.
• Hold ZERO for 10 seconds. The display will
show for 2 seconds “F.CAL” and "761" appears.
The factory calibration is automatically restored
and the instrument is ready for measurement.
BATTERY REPLACEMENT
Battery replacement must only take place in a
non-hazardous area.
Simply slide off the battery cover on the back of
the meter. Detach the battery from the terminals
and attach a fresh 9V battery while paying attention
to the correct polarity. Insert the battery and replace
the cover.
PRELIMINARY EXAMINATION
Please examine this product carefully. Make sure that the instrument is not damaged. If any
damage occured during shipment, please notify your Dealer.
Each HI 95761 Portable Meter is supplied complete with:
• Two Sample Cuvets and Caps
• 9V Battery
• Scissors
• Two CAL CHECK™ Cuvets (HI 95761-11) with Quality Certificate
• Tissue for wiping cuvets
• Instruction Manual and Quick Reference Guide
• Instrument Quality Certificate
• Rigid carrying case
9V
SLID
OFF
ACCESSORIES
REAGENT SETS
HI 95761-01 Reagents for 100
HI 95761-03 Reagents for 300
OTHER ACCESSORIES
HI 95761-11 CAL CHECK™ Standard Cuvets
HI 710009 Blue rubber boot
HI 710010 Orange rubber boot
HI 721310 9V battery (10 pcs)
HI 731318 Tissue for wiping cuvets (4 pcs)
HI 731331 Glass cuvets (4 pcs)
HI 731335 Caps for cuvets (4 pcs)
HI 93703-50 Cuvets cleaning solution (230 mL)
Total Chlorine LR tests
Total Chlorine LR tests
(1 set)
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Note:save all packing material until you are sure that the instrument works correctly. Any
defective item must be returned in its original packing.
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GENERAL DESCRIPTION
The HI 95761 is an auto diagnostic portable microprocessor meter that benefits from Hanna’s
years of experience as a manufacturer of analytical instruments. It has the advanced optical
system based on a special tungsten lamp and a narrow band interference filter that allows most
accurate and repeatable readings. All instruments are factory calibrated and the electronic and
optical design minimizes the need of frequent calibration.
With the powerful CAL CHECK™ validation function you are able to validate good performance of
your instrument at any time. The validation procedure is extremely user friendly. Just use the
exclusive Hanna ready-made, NIST traceable standards to verify the performance of the instrument
and recalibrate if necessary.
All instruments are splash waterproof and the lamp and filter units are protected from dust or dirt
by a transparent cup. This makes the instruments fulfill field applications. Display codes aid the
user in routine operation. The meter has an auto-shut off feature that will turn off the instrument
after 10 minutes of non use or after 1 hour if left in the calibration mode.
The meter uses an exclusive positive-locking system to ensure that the cuvet is in the same
position every time it is placed into the measurement cell. It is designed to fit a cuvet with a larger
neck making it easier to add both sample and reagents. The cuvet is made from special optical
glass to obtain best results.
The HI 95761 portable meter measures the total chlorine (Cl
0.000 to 0.500 mg/L (ppm) range. The method is an adaption of the USEPA METHOD 330.5 for
wastewater.
The reagent is in
to ensure the maximum repeatability.
powder form and is supplied in packets. The amount of reagent is precisely dosed
) content in water samples in the
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• Press READ/TIMER and “SIP” will blink during
measurement.
• The instrument will show for three seconds the
CAL CHECK™ standard value.
Then the date of last calibration (e.g.: “01.08”)
appears on the display, or “01.01” if the factory
calibration was selected. In both cases the
number of the month is blinking, ready for date
input.
Note: if the display shows “ERR” the calibration
procedure failed. Verify that both CAL CHECK™
Standards HI 95761-11 Cuvets, A and B, are
free from fingerprints or dirt and that they are
inserted correctly.
DATE INPUT
• Keep READ/TIMER pressed to scroll to the desired
month number (01-12).
• When the correct month has been set, press
ZERO to confirm. Now the display will show the
day number blinking. Keep READ/TIMER pressed
to scroll to the desired day number (01-31).
Note: it is possible to change from day to
month and vice versa by pressing ZERO.
or
ABBREVIATIONS
degree Celsius
°C:
US Environmental Protection Agency
EPA:
°F:
degree Fahrenheit
mg/L:
milligrams per liter. mg/L is equivalent to ppm (part per million)
milliliter
mL:
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• When both the day and month have been
selected, hold CAL CHECK
store date and calibration values. The instrument
will show for one second “Stor”, to confirm that
the new calibration data has been accepted.
• The instrument will return automatically to the
measurement mode by displaying "761" on
the LCD.
for three seconds to
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CALIBRATION PROCEDURE
SPECIFICATIONS
Note: it is possible to interrupt calibration procedure at any time by pressing ON/OFF.
Warning: do not validate or calibrate the instrument with standard solutions other than the Hanna
CAL CHECK™ Standards, otherwise erroneous results will be obtained.
CALIBRATION PROCEDURE
• Turn the meter on by pressing ON/OFF.
• When the LCD displays “761”, it is ready.
• Enter the calibration mode by holding CAL CHECK
for three seconds.
• The date of the last calibration appears (e.g.:
month “01”, day “08”). “F.CAL” means that
the factory calibration is selected.
Note: at this point it is possible to reset the
instrument to restore FACTORY CALIBRATION,
see instructions page 18.
• Place the CAL CHECK™ Standard Cuvet A into
the holder and ensure that the notch on the cap
is positioned securely into the groove.
• Press ZERO and “SIP” will blink on the display.
• After a few seconds the display will show
“-0.0-”. The meter is now zeroed and ready for
calibration.
• Remove the cuvet.
• Place the CAL CHECK™ Standard HI 95761-11
Cuvet B into the holder and ensure that the
notch on the cap is positioned securely into the
groove.
or
Range 0.000 to 0.500 mg/L
Resolution 0.001 mg/L
Precision ±0.004 mg/L @ 0.200 mg/L
Typical EMC Deviation ±0.001 mg/L
Light Source Tungsten lamp with narrow band interference filter @ 525 nm
Light Detector Silicon Photocell
Method Adaptation of the USEPA METHOD 330.5. The reaction between the
chlorine and the DPD reagent causes a pink tint in the sample.
Environment 0 to 50°C (32 to 122°F); max 95% RH non-condensing
Battery Type 1 x 9 volt
Auto-Shut off
Dimensions 180 x 83 x 46 mm (7.1 x 3.3 x 1.8")
Weight 290 g (10 oz.).
REQUIRED REAGENTS
Code Description Quantity/test
HI 95761-0 Total Chlorine LR Reagent 1 packet
After 10' of non-use in measurement mode;
after 1 hour of non-use in calibration mode.
PRECISION AND ACCURACY
Precision is how closely repeated
measurements agree with each other.
Precision is usually expressed as standard
deviation (SD).
Accuracy is defined as the nearness of a
test result to the true value.
Although good precision suggests good
accuracy, precise results can be inaccurate.
The figure explains these definitions.
In a laboratory using a standard solution of
0.200 mg/L chlorine and a representative
lot of reagent, an operator obtained with a
single instrument a standard deviation of
0.004 mg/L.
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PRINCIPLE OF OPERATION
VALIDATION PROCEDURE
Absorption of Light is a typical phenomenon of interaction between electromagnetic radiation and
matter. When a light beam crosses a substance, some of the radiation may be absorbed by atoms,
molecules or crystal lattices.
If pure absorption occurs, the fraction of light absorbed depends both on the optical path length
through the matter and on the
physical-chemical characteristics of the substance according to the
Lambert-Beer Law:
= ε
-log I/I
c d
o
λ
or
A = ε
c d
λ
Where:
-log I/I
= Absorbance (A)
o
I
= intensity of incident light beam
o
I = intensity of light beam after absorption
= molar extinction coefficient at wavelength λ
ε
λ
c = molar concentration of the substance
d = optical path through the substance
Therefore, the concentration "c" can be calculated from the absorbance of the substance as the
other factors are known.
Photometric chemical analysis is based on the possibility to develop an absorbing compound from
a specific chemical reaction between sample and reagents. Given that the absorption of a
compound strictly depends on the wavelength of the incident light beam, a narrow spectral
bandwidth should be selected as well as a proper central wavelength to optimize measurements.
The optical system of Hanna's HI 95 series colorimeters is based on special subminiature tungsten
lamps and narrow-band interference filters to guarantee both high performance and reliable
results.
Use the validation procedure to ensure that the instrument is properly calibrated.
Warning: do not validate or calibrate the instrument with standard solutions other than the Hanna
CAL CHECK™ Standards, otherwise erroneous results will be obtained.
Temperature correction for Validation: corrected value = read value × [1 + 0.002 × (20 − T(°C))]
corrected value = read value × [1 + 0.001 × (68 − T(°F))]
• Turn the meter on by pressing ON/OFF.
• When the LCD displays “761”, it is ready.
• Place the CAL CHECK™ Standard Cuvet A into
the holder and ensure that the notch on the cap
is positioned securely into the groove.
• Press ZERO and “SIP” will blink on the display.
• After a few seconds the display will show
“-0.0-”. The meter is now zeroed and ready for
validation.
• Remove the cuvet.
• Place the CAL CHECK™ Standard HI 95761-11
Cuvet B into the holder and ensure that the
notch on the cap is positioned securely into the
groove.
• Press CAL CHECK and “SIP” will blink during
measurement.
HI 95 series block diagram (optical layout)
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• Wait for a few seconds and the display will show the validation standard value.
The reading should be within specifications as reported on the CAL CHECK™ Standard
Certificate. If the value is found out of specifications, please check that the cuvets are free of
fingerprints, oil or dirt and repeat validation. If results are still found out of specifications then
recalibrate the instrument.
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• Hold READ/TIMER for three seconds. The
display will show the countdown prior to
measurement.
Alternatively, wait for 2 minutes and 30 seconds
and just press READ/TIMER.
In both cases “SIP” will blink during
measurement.
• The instrument directly displays concentration
in mg/L of total chlorine on the Liquid Crystal
Display.
INTERFERENCES
• Alkalinity:
above 1,000 mg/L CaCO
pH < 8.3); above 250 mg/L CaCO
sample pH > 9.0).
In both cases, it will not reliably develop the full amount of color
or it may rapidly fade (negative error). To resolve this, neutralize
the sample with diluted HCl.
or
if present as bicarbonate (HCO
3
if present as carbonate (CO
3
-
, sample
3
A microprocessor controlled special tungsten lamp emits radiation which is first optically conditioned
and beamed to the sample contained in the cuvet. The optical path is fixed by the diameter of the
cuvet. Then the light is spectrally filtered to a narrow spectral bandwidth, to obtain a light beam of
intensity I
or I.
o
The photoelectric cell collects the radiation I that is not absorbed by the sample and converts it
into an electric current, producing a potential in the mV range.
The microprocessor uses this potential to convert the incoming value into the desired measuring
unit and to display it on the LCD.
The measurement process is carried out in two phases: first the meter is zeroed and then the actual
measurement is performed.
The cuvet has a very important role because it is an optical element and thus requires particular
attention. It is important that both the measurement and the calibration (zeroing) cuvets are
optically identical to provide the same measurement conditions. Whenever possible use the same
cuvet for both. It is necessary that the surface of the cuvet is clean and not scratched. This to avoid
2-
,
3
measurement interference due to unwanted reflection and absorption of light. It is recommended
not to touch the cuvet walls with hands.
Furthermore, in order to maintain the same conditions during the zeroing and the measuring
phases, it is necessary to close the cuvet to prevent any contamination.
• Acidity:
• Hardness:
• Bromine (Br2):
• Chlorine dioxide (ClO2):
• Iodine (I2):
• Oxidized Manganese
and Chromium:
• Ozone
(O3):
above 150 mg/L CaCO3. May not reliably develop the full amount
of color or it may rapidly fade (negative error). To resolve this,
neutralize the sample with diluted NaOH.
in case of water with hardness greater than 500 mg/L CaCO
shake the sample for approximately 2 minutes after adding the
powder reagent.
positive error.
positive error.
positive error.
positive error.
positive error.
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FUNCTIONAL DESCRIPTION
,
3
1) Liquid Crystal Display (LCD)
2) Cuvet Holder
3) Cuvet alignment indicator
4) ON/OFF key
5) ZERO key
6) READ/TIMER key
7) CAL CHECK key
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KEYPAD DESCRIPTION
• ON/OFF: to turn the meter on and off.
• ZERO: to zero the meter prior to measurement.
• READ/TIMER: this is a bi-functional key, just press for making a measurement, or hold the key
for 3 seconds to start a pre-programmed countdown prior to measurement.
• CAL CHECK: this bi-functional key allows to perform validation of the instrument just pressing
the CAL CHECK key, or hold the key for 3 seconds to enter the calibration mode.
OPERATING MODES
• Measurement mode: default operation mode, enables both validation and measurement.
• Calibration mode: may be entered by keeping CAL CHECK pressed
icon appears), it enables calibration of the instrument.
DISPLAY ELEMENTS DESCRIPTION
1) four digit main display area.
2) CAL: appears when the instrument operates in the calibration mode.
3) the Month and Day icons appear above the number of month and day when a date is
displayed.
4) the blinking “Battery” icon appears when the battery voltage is getting low.
for three seconds (the “CAL”
MEASUREMENT PROCEDURE
Turn the meter on by pressing ON/OFF and follow instruction manual to perform either the
MEASUREMENT, VALIDATION or CALIBRATION PROCEDURE.
MEASUREMENT PROCEDURE
• Turn the meter on by pressing ON/OFF.
• When the LCD displays “761”, it is ready.
• Fill the cuvet with 10 mL of unreacted sample,
up to the mark, and replace the cap.
• Place the cuvet into the holder and ensure that
the notch on the cap is positioned securely into
the groove.
• Press ZERO and “SIP” will blink on the display.
• After a few seconds the display will show
“ -0.0- ”. The meter is now zeroed and ready for
measurement.
• Remove the cuvet.
• Add the content of one packet of HI 95761-0
Total Chlorine Low Range reagent. Replace the
cap and shake gently for 20 seconds.
• Replace the cuvet into the holder and ensure
that the notch on the cap is positioned securely
into the groove.
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• It is important that the sample does not contain
any debris. This would corrupt the reading.
GUIDE TO DISPLAY CODES
• Each time the cuvet is used, the cap must be
tightened to the same degree.
• Whenever the cuvet is placed into the measurement
cell, it must be dry outside, and completely free of
fingerprints, oil or dirt. Wipe it thoroughly with
HI 731318 (tissue for wiping cuvets, see chapter
ACCESSORIES) or a lint-free cloth prior to insertion.
• Shaking the cuvet can generate bubbles in the
sample, causing higher readings. To obtain accurate
measurements, remove such bubbles by swirling
or by gently tapping the vial.
• Do not let the reacted sample stand too long after
reagent is added, or accuracy will be lost.
• It is possible to take multiple readings in a row,
but it is recommended to take a new zero reading
for each sample and to use the same cuvet for
zeroing and measurement.
• After the reading it is important to discard
immediately the sample, otherwise the glass might
become permanently stained.
• All the reaction times reported in this manual are
referred to 20°C (68°F). As a general rule of
thumb, they should be doubled at 10°C (50°F)
and halved at 30°C (86°F).
• In order to maximize accuracy, prior to a
measurement follow the validation procedure to
be sure that the instrument is properly calibrated.
If necessary, calibrate the instrument.
This prompt appears for 1 second each time the instrument is
turned on.
This indicates that the meter is in a ready state and zeroing can be
performed.
Sampling in Progress. This
meter is performing a measurement.
This indicates that the meter is in a zeroed state and measurement
can be performed.
Light over range: the cuvet is not inserted correctly and an excess
ambient light is reaching the detector. If the cover is properly
installed, then contact your dealer or the nearest Hanna Customer
Service Center.
The blinking "BAT" indicates that the battery voltage is getting low
and the battery needs to be replaced.
This indicates that the battery is dead and must be replaced. Once
this indication is displayed, the meter will lock up. Change the
battery and restart.
“Configuration”: this indicates that the meter has lost its
configuration. Contact your dealer or the nearest Hanna Customer
Service Center.
CALIBRATION MODE MESSAGES
The date of the last calibration appears on the LCD each time the
calibration mode is entered. If calibration is performed for the first
time, “F.CAL” appears.
This indicates that the factory calibration is selected.
flashing prompt appears each time the
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The flashing digits indicate that:
1) the month can be set
2) the day can be set
“Storage”: this prompt appears for 1 second at the end of the
calibration procedure, to indicate that the calibration data has
been stored.
“Error”: the concentration of the calibration solution used is not
correct. Repeat the calibration procedure with the right standard
solution, and verify it is not expired. If the calibration procedure fails
again, contact your dealer or the nearest Hanna Customer Service
Center.
ERROR MESSAGES
a) on zero reading
This indicates that the zeroing procedure failed due to a low signal-tonoise ratio. In this case press ZERO again.
“No Light”: the instrument cannot adjust the light level. Please check
that the sample does not contain any debris.
Under range. A blinking "0.000" indicates that the sample absorbs
less light than the zero reference. Check the procedure and make
sure you use the same cuvet for reference (zero) and measurement.
A flashing value of the maximum concentration indicates an over
range condition. The concentration of the sample is beyond the
programmed range: dilute the sample and re-run the test.
A flashing value lower than the maximum concentration indicates
a low signal-to-noise ratio condition. In this case accuracy of the
result is not guaranteed. Repeat the measurement procedure.
GENERAL TIPS FOR AN ACCURATE MEASUREMENT
The instructions listed below should be carefully followed during testing to ensure best accuracy.
• For a correct filling of the cuvet: the liquid in the
cuvet forms a convexity on the top; the bottom
of this convexity must be at the same level of
the 10 mL mark.
“Light Low”: there is not enough light to perform a measurement.
Please check the preparation of the zero cuvet.
“Light High”: there is too much light to perform a measurement.
Please check the preparation of the zero cuvet.
b) on sample reading
There is too much light for the sample measurement. Please check if
the right sample cuvet is inserted.
“Inverted”: the sample and the zero cuvet are inverted.
“Zero”: a zero reading was not taken. Follow the instruction in the
measurement procedure for zeroing the meter.
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• Proper use of the powder reagent packet:
(a) use scissors to open the powder packet;
(b) push the edges of the packet to form a spout;
(c) pour out the content of the packet.
(a)
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(b)
(c)
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