Hanna Instruments HI 96761C User manual

INSTRUCTION MANUAL
HI96761C
Total Chlorine Meter for the
Analysis of Trace Total Chlorine
Concentrations

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.
Thank you for choosing a Hanna Instruments product.
Please read this instruction manual carefully before using the instrument.
This manual will provide you with the necessary information for correct use of
the instrument, as well as a precise idea of its versatility.
If you need additional technical information, do not hesitate to e‑mail us at
[email protected] or view our worldwide contact list at www.hannainst.com.
Dear
Customer,

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TABLE OF CONTENTS
PRELIMINARY EXAMINATION ............................................................................................
GENERAL DESCRIPTION ....................................................................................................
ABBREVIATIONS ..............................................................................................................
SPECIFICATIONS ..............................................................................................................
PRECISION AND ACCURACY ..............................................................................................
PRINCIPLE OF OPERATION ...............................................................................................
FUNCTIONAL DESCRIPTION ...............................................................................................
ERRORS AND WARNINGS .................................................................................................
GENERAL TIPS FOR AN ACCURATE MEASUREMENT .............................................................
STARTUP ........................................................................................................................
MEASUREMENT PROCEDURE ............................................................................................
VALIDATION PROCEDURE .................................................................................................
CALIBRATION PROCEDURE ...............................................................................................
GLP ................................................................................................................................
BATTERY MANAGEMENT ...................................................................................................
BATTERY REPLACEMENT ...................................................................................................
ACCESSORIES ..................................................................................................................
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Please examine this product carefully. Make sure that the instrument is not damaged. If any damage
occurred during shipment, please contact your local Hanna Instruments Office.
Each HI96761 Ion Selective Meter is supplied complete with:
• Sample Cuvettes and Caps (2 pcs.)
• CAL Check™ standard cuvettes
• 9V Battery
• Scissors
• Cloth for wiping cuvettes
• Instrument Quality Certificate
• Instruction Manual and Quick Reference Guide
• 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.
PRELIMINARY EXAMINATION

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The HI96761 is an auto diagnostic portable microprocessor meter that benefits from
Hanna Instruments’ years of experience as a manufacturer of analytical instruments. It has an
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 Instruments ready‑made, NIST traceable standards to verify the performance of
the instrument and recalibrate if necessary.
All instruments are splash proof 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 HI96761 meter measures the total chlorine (Cl2) content in water samples in the 0.000 to
0.500 mg/L (ppm) range. The method is an adaptation of the Standard Method 4500‑Cl G for
drinking water.
The reagent is in powder form and is supplied in packets. The amount of reagent is precisely dosed
to ensure the maximum repeatability.
GENERAL DESCRIPTION
degree Celsius
degree Fahrenheit
Liquid Crystal Display
milligrams per liter. mg/L is equivalent to ppm (parts per million)
milliliter
millivolt
°C:
°F:
LCD:
mg/L:
mL:
mV:
ABBREVIATIONS

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SPECIFICATIONS
Range 0.000 to 0.500 mg/L
Resolution 0.001 mg/L
Accuracy
@25 °C (77 °F) ±0.020 mg/L ±3% of reading
Light Source Tungsten lamp
Light Detector Silicon Photocell with narrow band interference filter @525 nm
Method Adaptation of the Standard Method 4500‑Cl G. 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 9V (1 pc.)
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 320 g (11.3 oz.).
REQUIRED REAGENTS
Code Description Quantity/test
HI95761‑0 DPD Powder Reagent 1 packet

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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.
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
ε
λ= 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.
PRINCIPLE OF OPERATION
PRECISION AND ACCURACY

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PRINCIPLE OF OPERATION
The optical system of Hanna Instruments’ HI96 series colorimeter is based on special subminiature
tungsten lamps and narrow‑band interference filters to guarantee both high performance and
reliable results.
HI96 series block diagram (optical layout)
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.

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INSTRUMENT DESCRIPTION
1) 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
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 pressing GLP/ (“GLP” appears), it enables consulting of
user calibration date or restore factory calibration.
KEYPAD DESCRIPTION
• ON/OFF: to turn the meter on and off.
• ZERO/CFM: to zero the meter prior to measurement, to confirm edited values or 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.
• GLP/ : this is a bi‑functional key. Just press to enter GLP mode. In calibration mode press
to edit the date and time.

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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 shows the charging level of the battery
4) The hourglass appears when an internal checking 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
FUNCTIONAL DESCRIPTION
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.
Light High: There is too much light to perform a measurement.
Please check the preparation of the zero cuvette.
a) on zero reading
ERRORS AND WARNINGS
Light Low: There is not enough light to perform a measurement.
Please check the preparation of the zero cuvette.