Hanna Instruments HI 96741C User manual

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www.hannainst.com
Instruction Manual
HI 96741C
Total Hardness and Iron LR
ISM

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TABLE OF CONTENTS
PRELIMINARY EXAMINATION ................................................................................................ 4
GENERAL DESCRIPTION ....................................................................................................... 5
ABBREVIATIONS .................................................................................................................. 5
SPECIFICATIONS ................................................................................................................... 6
PRECISION AND ACCURACY .................................................................................................. 6
PRINCIPLE OF OPERATION ................................................................................................... 7
FUNCTIONAL DESCRIPTION .................................................................................................. 9
ERRORS AND WARNINGS .................................................................................................. 11
GENERAL TIPS FOR AN ACCURATE MEASUREMENT ............................................................. 13
STARTUP ........................................................................................................................... 15
RANGE SELECTION ............................................................................................................. 15
MEASUREMENT PROCEDURE ............................................................................................. 16
VALIDATION PROCEDURE ................................................................................................... 18
CALIBRATION PROCEDURE ................................................................................................. 20
GLP ................................................................................................................................... 23
BATTERY MANAGEMENT .................................................................................................... 24
BATTERY REPLACEMENT .................................................................................................... 24
ACCESSORIES ..................................................................................................................... 25
WARRANTY........................................................................................................................ 26
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 [email protected].
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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GENERAL DESCRIPTION
ABBREVIATIONS
The HI 96741 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 CHECKTM 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 messages 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 in measurement mode or after 1 hour if left in
calibration mode .
The meter uses an exclusive positive-locking system to ensure that the cuvette is in the same
position every time it is placed into the measurement cell. It is designed to fit a cuvette with a
larger neck making it easier to add both sample and reagents. The cuvette is made from special
optical glass to obtain best results.
The HI 96741 meter measures the free and total chlorine (Cl2) content in water samples in the
0.00 to 5.00 mg/L (ppm) range. The method is an adaptation of the USEPA Method 330.5 for
wastewater, and Standard Method 4500-Cl G for drinking water.
The reagents are in powder form and supplied in packets. The amount of reagent is precisely
dosed to ensure the maximum repeatability.
degree Celsius
degree Fahrenheit
US Environmental Protection Agency
milligrams per liter. mg/L is equivalent to ppm (parts per million)
milliliter
millivolts
°C:
°F:
USEPA:
mg/L:
mL:
mV:
PRELIMINARY EXAMINATION
Please examine this product carefully. Make sure that the instrument is not damaged. If any
damage occurred during shipment, please notify your Dealer.
Each HI 96741C Ion Selective Meter is supplied complete with:
• Two Sample Cuvettes and Caps
• CAL CHECK standard cuvettes
• 9V Battery
• Scissors
• Cloth for wiping cuvettes
• Instruction Manual
• Instrument Quality Certificate
• Rigid carrying case
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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PRINCIPLE OF OPERATION
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:
-log I/Io= ελc d
or
A = ελc d
Where:
-log I/Io=Absorbance (A)
Io=intensity of incident light beam
I=intensity of light beam after absorption
ελ=molar extinction coefficient at wavelength 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 96 series colorimeters is based on special subminiature
tungsten lamps and narrow-band interference filters to guarantee both high performance and
reliable results.
HI 96 series block diagram (optical layout)
SPECIFICATIONS
PRECISION AND ACCURACY
Range Mg Hardness 0.00 to 2.00 mg/L
Ca Hardness 0.00 to 2.70 mg/L
Total Hardness 0.00 to 4.70 mg/L
Iron LR 0.00 to 1.60 mg/L
Resolution 0.01 mg/L Total Hardness
0.01 mg/L Iron LR
Accuracy Mg Hardness ±0.11 mg/L ±5% of reading @ 25°C
Ca Hardness ±0.11 mg/L ±5% of reading @ 25°C
Iron LR ±0.01 mg/L ±8% of reading @ 25°C
Typical EMC Deviation ±0.02 mg/L Mg Hardness
±0.02 mg/L Ca Hardness
±0.01 mg/L Iron LR
Light Source Tungsten lamp
Light Detector Silicon Photocell with narrow band interference filter @ 525nm.
Method For Total Hardness: Adaptation of the Standard Methods for the Examination
of Water and Wastewater, 18th Edition,
colorimetric method. The reaction
between Mg/Ca and reagents causes a violet tint in the sample.
For Iron LR: Adaptation of the TPTZ method. The reaction between iron and
the reagent causes a violet 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 After 10' of non-use in measurement mode ;
after 1 hour of non-use in calibration mode ;
with last reading reminder.
Dimensions 192 x 104 x 69 mm (7.6 x 4.1 x 2.7")
Weight 360 g (12.7 oz.).
REQUIRED REAGENTS
Code Unit Description Quantity/test
HI93719A-0 Hardness Ca and Mg Reagent 0.5 mL
HI93719B-0 Hardness Alkaly Solution 0.5 mL
HI93719C-0 Hardness EDTA Solution 1 drop
HI93719D-0 Hardness EGTA Solution 1 drop
HI93741-0 Iron LR TPTZ Reagent 1 packet
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 1.00 mg/L chlorine and a representative
lot of reagent, an operator obtained with a single
instrument a standard deviation of 0.02 mg/L.

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1) RANGE/GLP/ key
2) CAL CHECK key
3) ZERO/CFM key
4) READ/ /TIMER key
5) ON/OFF key
6) Liquid Crystal Display (LCD)
7) Cuvette alignment indicator
8) Cuvette holder
FUNCTIONAL DESCRIPTION
A microprocessor controlled special tungsten lamp emits radiation which is first optically
conditioned and beamed to the sample contained in the cuvette. The optical path is fixed by the
diameter of the cuvette. Then the light is spectrally filtered to a narrow spectral bandwidth, to
obtain a light beam of intensity Ioor I.
The photoelectric cell collects the radiation Ithat 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 cuvette 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)
cuvettes, are optically identical to provide the same measurement conditions. Whenever possible
use the same cuvette for both. It is necessary that the surface of the cuvette is clean and not
scratched. This to avoid measurement interference due to unwanted reflection and absorption of
light. It is recommended not to touch the cuvette walls with hands.
Furthermore, in order to maintain the same conditions during the zeroing and the measuring
phases, it is necessary to close the cuvette to prevent any contamination.
INSTRUMENT DESCRIPTION
KEYPAD DESCRIPTION
•ON/OFF: to turn the meter on and off.
•ZERO/CFM: this is a bi-functional key. Just press to zero the meter prior to measurement,
or confirm edited values. In calibration mode press to confirm factory calibration restore.
•READ/ /TIMER: this is a multi-functional key. In measurement mode , press to make a
measurement, or press and hold for three seconds to start a pre-programmed countdown prior
to measurement. In GLP mode press to view the next screen.
•CAL CHECK: this is a bi-functional key. Just press to perform the validation of the meter, or
press and hold for three seconds to enter calibration mode .
•RANGE/GLP/ : this is a multi-functional key. Just press to change the parameter. Press
and hold for three seconds to enter GLP mode . In calibration mode press to edit the date and time.
OPERATING MODES
• Measurement mode: default operation mode, enables both validation and measurement.
• Calibration mode: may be entered by keeping CAL CHECK pressed for three seconds (the
“CAL” tag appears), it enables calibration of the instrument.
• GLP mode: may be entered by keeping RANGE/GLP/ pressed for three seconds (“GLP”
appears), it enables consulting of user calibration date or restore factory calibration.

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ERRORS AND WARNINGS
The instrument shows clear messages when erroneous condition appears. Messages are also displayed
when the obtained values are outside expected range. The beeper is playing a beep on errors.
a) on zero reading
Light High: There is too much light to perform a measurement.
Please check the preparation of the zero cuvette.
Light Low: There is not enough light to perform a measurement.
Please check the preparation of the zero cuvette.
No Light: The instrument cannot adjust the light level. Please
check that the sample does not contain any debris.
Inverted cuvettes: The sample and the zero cuvette are inverted.
Zero: A zero reading was not taken. Follow the instructions of
the measurement procedure for zeroing the meter.
b) on sample reading
DISPLAY ELEMENTS DESCRIPTION
1) The measuring scheme (lamp, cuvette, detector), appears during different phases of zero or
reading measurement
2) Error messages and warnings
3) The battery icon indicates the charge state of the battery
4) The hourglass appears when an internal check is in progress
5) Status messages
6) The chronometer appears when the reaction timer is running
7) The month, day and date icons appear when a date is displayed
8) Four digit main display
9) Measuring units
10) Four digit secondary display
10
8
5
2
9
7
3
4
6
1

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The instructions listed below should be carefully followed during testing to ensure best accuracy.
•Color or suspended matter in large amounts may cause
interference, therefore these should be removed by
treatment with active carbon and by prior filtration.
•For a correct filling of the cuvette: the liquid in the
cuvette forms a concavity on the top; the bottom of this
concavity must be at the same level of the 10 mL mark.
•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.
GENERAL TIPS FOR AN ACCURATE MEASUREMENT
Battery low: The battery must be replaced soon.
Dead battery: This indicates that the battery is dead and must
be replaced. Once this indication is displayed, normal operation
of the instrument will be interrupted. Change the battery and
restart the meter.
Under range: A blinking “0.00” indicates that the sample
absorbs less light than the zero reference. Check the procedure
and make sure you use the same cuvette for reference (zero) and
measurement.
Over Range: 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.
c) during calibration procedure
Standard Low: The standard reading is less than expected.
Standard High: The standard reading is higher than expected.
Cap error: Appears when external light enters in the analysis
cell. Assure that the cuvette cap is present.
Cooling lamp: The instrument waits for the lamp to cool down.
d) other errors and warnings

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•Press RANGE/GLP/ to change the range.
The range can be changed any time when the
instrument is in measurement mode .
The selected range is memorized and the selection
remaines unchanged at power off or when the
battery is removed.
Code Parameter
P1 Total Hardness
P2 Iron Low Range
The HI 96741 can measure Free chlorine when range P1 is selected or Total chlorine when
range P2 is selected. To change the active range follow the procedure:
•Turn the meter on by pressing ON/OFF. The
display briefly shows all tags on.
•After startup, the range identification number is
displayed on the secondary LCD as P1 or P2.
RANGE SELECTION
STARTUP
Prepare the instrument for measurement as follows:
•Unpack the instrument by removing the dust protection sleeve from the instrument cuvette
holder.
•Place the battery in the instrument as described in the “BATTERY REPLACEMENT” chapter.
•Place the instrument on a flat table.
•Do not place the instrument under direct sun light.
•It is important that the sample does not contain any debris.
This would corrupt the reading.
•Each time the cuvette is used, the cap must be tightened
to the same degree.
•Whenever the cuvette 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
or a lint-free cloth prior to insertion.
•Shaking the cuvette can generate bubbles in the sample, causing higher readings. To obtain
accurate measurements, remove such bubbles by swirling or by gently tapping the cuvette.
•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 cuvette 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.

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•Place the cuvette into the cuvette holder and
ensure that the notch on the cap is positioned
securely into the groove.
•Press ZERO/CFM and the lamp, cuvette and
detector icons will appear on the display,
depending on the measurement phase.
•For Total Hardness: Place the ZERO sample
into the holder and ensure that the notch on
the cap is positioned securely into the groove.
Press ZERO/CFM and the lamp, cuvette and
detector icons will appear on the display,
depending on the measurement phase. After a
few seconds the display will show “-0.0-”.
Remove the ZERO sample and insert the READ1
sample into the instrument. Press and hold
READ/ /TIMER for three seconds.The display
will show the countdown prior to measurement.
The beeper is playing a beep at the end of
countdown period. Alternatively, wait for 30
seconds. The lamp, cuvette and detector icons
will appear on the display, depending on the
measurement phase, then the instrument will
display the level of Magnesium hardness in
mg/L CaCO3(togheter with “n”).
•After a few seconds the display will show “-
0.0-”. The meter is now zeroed and ready for
measurement.
•Remove the cuvette.
•Add the specific test reagent for each parameter:
Total hardness: the third cuvette (nothing is
added)
Iron LR: Fill one graduated mixing cylinder up
to the 25 mL mark with the sample.
Add the content of one packet of HI 93741-0
reagent, close the cylinder and shake well for
30 seconds.
Fill a cuvette with 10 mL of the reacted
sample up to the mark and replace the cap.
To compensate the meter for the sample turbidity or color, the measurement takes place in two
phases. First, the meter is zeroed using the unreacted sample. After the reagents are added the
reacted sample is measured.
Important note:Free and Total Chlorine have to be measured separately with fresh unreacted
samples if both values are requested.
MEASUREMENT PROCEDURE
•Turn the meter on by pressing ON/OFF. The
display briefly shows all tags on.
•When the beeper sounds briefly and the LCD
displays dashes, the meter is ready. The
blinking “ZERO” indicates that the instrument
needs to be zeroed first.
•Pay attention to the selected range.
To change the range, simply press RANGE/
GLP/ .
•For Total Hardness: Fill a graduated beaker
up to the 50mL mark with the sample. Add
0.5 mL of HI 93719A-0 Calcium And
Magnesium Reagent indicator solution and
mix. Add 0.5 mL of HI 93719B-0 Alkali
solution for Calcium and Magnesium and mix.
Fill three cuvettes with 10mL of sample each.
Add 1 drop of HI 93719C-0 EDTA solution
to one cuvette, replace the cap and swirl the
solution. This is the ZERO sample. Add 1 drop
of HI 93719D-0 EGTA solution to the second
cuvette, replace the cap and swirl the solution.
This is the READ1 sample.
For Iron LR: Fill one graduated mixing cylinder
up to the 25 mL mark with deionized water.
Add the content of one packet of HI 93741-0
reagent, close the cylinder and shake well for
30 seconds. This is the blank.
Fill a cuvette with 10 mL of the blank up to
the mark and replace the cap.
#1
#2
#3
#1
#2
or

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The reading should be within specifications as reported in the CAL CHECKTM Standard
Certificate. If the value is found out of the specifications, please check that the cuvettes are free
of fingerprints, oil or dirt and repeat validation. If results are still found out of specifications,
then recalibrate the instrument.
•Turn the meter on by pressing ON/OFF.
•When the beeper sounds briefly and the LCD
displays dashes, the meter is ready.
•Place the CAL CHECKTM Standard Cuvette
A into the cuvette holder and ensure that the
notch on the cap is positioned securely into
the groove.
•Press ZERO/CFM and the lamp, cuvette and
detector icons will appear on the display,
depending on the measurement phase.
•After a few seconds, the display will show
“-0.0-”. The meter is now zeroed and ready
for validation.
•Remove the cuvette.
•Place the specific CAL CHECKTM Standard
Cuvette B into the cuvette holder, for:
Hardness:B, HI 96719-11
or
Iron LR:B,HI 96741-11
Ensure that the notch on the cap is positioned
securely into the groove.
•Press CAL CHECKTM and the lamp, cuvette
and detector icons together with “CAL CHECK”
will appear on the display, depending on the
measurement phase.
•At the end of the measurement the display
will show the validation standard value.
INTERFERENCES
•Iron LR: Cadmium above 4.0 mg/L, Chromium6+ above 1.2 mg/L, Copper above 0.6 mg/L,
Manganese above 50.0 mg/L, Molybdenum above 4.0 mg/L, Nitrite ion above 0.8 mg/L, Chromium3+
above 0.25 mg/L, Cobalt above 0.05 mg/L, Cyanide above 2.8 mg/L, Mercury above 0.4 mg/L, Nickel
above 1.0 mg/L. Sample pH should be between 3 and 4 to avoid developed color to fade or turbidity
formation.
•Total Hardness: Excessive amounts of heavy metals.
Note:If the sample is very acidic, some extra drops of HI 93719B buffer reagent may be added.
VALIDATION PROCEDURE
Use the validation procedure to ensure that the instrument is properly calibrated.
Warning:Do not validate the instrument with any standard solutions other than the HANNA CAL
CHECKTM Standards, otherwise erroneous results will be obtained.
Note: The validation is performed only for the selected parameter. For full validation of the
instrument, the following procedure must be performed for each parameter.
•Replace the cap and swirl the solution.
•Replace the cuvette into the cuvette holder
and ensure that the notch on the cap is
positioned securely into the groove.
•Press and hold READ/ /TIMER for three
seconds. The display will show the countdown
prior to measurement. An audible “beep”
indicates the end of countdown period.
•Alternatively, wait for:
Iron LR:30 seconds
Then press READ/ /TIMER.
For Hardness press READ/ /TIMER directly.
In all cases the lamp, cuvette and detector
icons will appear on the display, depending
on the measurement phase.
•At the end of measurement, the instrument
directly displays concentration in mg/L of iron
or for hardness the instrument will display the
concentration of Calcium in mg/L CaCO3on the
LCD, depending on the selected parameter.
or