Hanna Instruments HI 96761C User manual

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www.hannainst.com
This Instrument is in
Compliance with the CE Directives
Instruction Manual
HI 96761C
Total Chlorine Meter
for the analysis of
trace Total Chlorine concentrations

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TABLE OF CONTENTS
PRELIMINARY EXAMINATION .............................................................................................. 3
GENERAL DESCRIPTION ...................................................................................................... 4
ABBREVIATIONS ................................................................................................................ 4
SPECIFICATIONS ................................................................................................................ 5
PRECISION AND ACCURACY ................................................................................................. 5
PRINCIPLE OF OPERATION .................................................................................................. 6
FUNCTIONAL DESCRIPTION ................................................................................................7
ERRORS AND WARNINGS ..................................................................................................9
GENERAL TIPS FOR AN ACCURATE MEASUREMENT ...........................................................11
STARTUP...................................................................................................................12
MEASUREMENT PROCEDURE ...........................................................................................13
VALIDATION PROCEDURE .................................................................................................15
CALIBRATION PROCEDURE ...............................................................................................17
GLP...........................................................................................................................20
BATTERY MANAGEMENT ..................................................................................................21
BATTERY REPLACEMENT ..................................................................................................22
ACCESSORIES .................................................................................................................22
WARRANTY .................................................................................................................23
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].
This instrument is in compliance with directives.
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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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 96761 Ion Selective Meter is supplied complete with:
• Two Sample Cuvets and Caps
• 9V Battery
• Scissors
• Tissue for wiping cuvets
• Instrument quality certificate
• Instruction Manual
• 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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GENERAL DESCRIPTION
ABBREVIATIONS
The HI 96761 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 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 96761 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.
degree Celsius
United States Environmental Protection Agency
degree Fahrenheit
milligrams per liter. mg/L is equivalent to ppm (part per million)
milliliter
millivolts
°C:
USEPA:
°F:
mg/L:
mL:
mV:

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SPECIFICATIONS
PRECISION AND ACCURACY
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
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 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 102 x 67 mm (7.6 x 4 x 2.6")
Weight 290 g (10 oz.).
REQUIRED REAGENTS
Code Description Quantity/test
HI 95761-0 DPD Powder 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 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
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)

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1) GLP/ key
2) CAL CHECK key
3) ZERO/CFM key
4) READ/ /TIMER key
5) ON/OFF key
6) Liquid Cristal Display (LCD)
7) Cuvet alignment indicator
8) Cuvet holder
FUNCTIONAL DESCRIPTION
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 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 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 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.
INSTRUMENT DESCRIPTION

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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.
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.
DISPLAY ELEMENTS DESCRIPTION
1) The measuring scheme (lamp, cuvet, 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

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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 cuvet.
Light Low: There is not enough light to perform a measurement.
Please check the preparation of the zero cuvet.
No Light:The instrument cannot adjust the light level. Please
check that the samples does not contain any debris.
Inverted cuvets: The sample and the zero cuvet are inverted.
Zero: A zero reading was not taken. Follow the instructions of
the measurement procedure for zeroing the meter.
b) on sample reading

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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.
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 cuvet cap is present.
Cooling lamp: The instrument waits for the lamp to cool down.
d) other errors and warnings