Hanna Instruments HI 9142 User manual

Instruction Manual
HI 9142
Portable Waterproof
Dissolved Oxygen Meter
www.hannainst.com

23
PRELIMINARY EXAMINATION
Removetheinstrumentfromthepackingmaterial
and examine it to make sure that no damage
has occurred during shipping. If there is any
damage,notifyyourDealer.
The meter is supplied complete with:
• HI 76407/4 DO probe with 4 m cable
•2sparemembraneswithO-rings
• HI 7041S electrolyte solution (30 mL)
•Calibrationscrewdriver
•Batteries (4 x 1.5V AA)
•Instructionmanual
•Ruggedcarryingcase
Note: Save all packing material until you are sure
that the instrument functions correctly. All
defective items must be returned to us in the
original packaging with the supplied
accessories.
GENERAL DESCRIPTION
HI 9142 is a rugged, waterproof meter that
solvesthecommonproblemsoffielduse,such
ascold, rain, snowand dust, thatcan damage
a meter, rapidly deteriorating its performance
andlife.
Itisverysimpletouse:calibrationisperformed
withHI7040zerooxygensolution,while100%
calibration is done in air.
The polarographic probe (HI 76407/4) is pro-
vided with a membrane covering the sensors
and a built-in thermistor for temperature mea-
surementandcompensation.Thethinperme-
able membrane isolates the sensor elements
from the testing solution, but allows oxygen to
enter. When a voltage is applied across the
sensor, oxygen that has passed through the
membranereactscausingcurrenttoflow,allow-
ingthedeterminationofoxygen.
DearCustomer,
Thank you for choosing a Hanna Instruments
Product.
Please read this instruction manual carefully
beforeusingtheinstrument.
Thismanualwillprovideyouwithalltheneces-
sary information for the correct use of the
instrument.
Ifyouneedadditionaltechnicalinformation,do
not hesitate to e-mail us at
[email protected]
This instrument is in compliance with the CE
directives.
TABLE OF CONTENTS
PreliminaryExamination ............................. 3
GeneralDescription..................................... 3
ProbeFunctionalDescription ...................... 4
MeterFunctionalDescription....................... 5
Specifications ............................................. 6
ProbeInitialPreparation .............................. 7
CalibrationProcedure .................................. 8
TakingMeasurements ............................... 10
AltitudeandSalinityCompensation ........... 11
Probe&MembraneMaintenance .............. 13
BatteryReplacement ................................ 15
Accessories.............................................. 16
Warranty ................................................... 17
CEDeclarationofConformity .................... 18

45
METERFUNCTIONAL DESCRIPTION
1. Batterycompartment
2. Probeconnector
3. LiquidCrystalDisplay
4. ON/OFFbutton
5. Calibrationbutton
6. Slopecalibrationtrimmer
7. Zerooxygencalibrationtrimmer
1. D.O.probe
2. Protectivecap
3. Shieldedcable
4. Polypropyleneprobebody
5. Temperaturesensor
6. O-Ringseal
7. Silverchloride(AgCl)anode
8. Platinumcathode(sensor)
9. Oxygenpermeablemembrane
10.Membranecap
PROBEFUNCTIONAL DESCRIPTION
9
1
3
4
4
5
6
7
8
9
2
10
8
7
6
The probe included with the meter is supplied
witha4m(13')cablethatallowsmeasurements
tobetakeneven in even hardtoreach
places. For applications that require longer
probecables,theHI76407/10andHI76407/20
probeswitha10m(33')or20m(67')cableare
available.

67
PROBE INITIAL PREPARATION
Probe Preparation
All D.O. probes from Hanna Instrument are
shipped dry. To hydrate the probe and pre-
pare it for use, connect it to the meter and
proceed as follows.
1. Remove the red & black plastic
cap. This cap is used for ship-
ping purposes only and can be
thrown away.
2. Wet the sensor by soaking the
bottom (2.5 cm/1") of the probe
in HI 7041S electrolyte solution
for 5 minutes.
3. Rinse the membrane
(HI 76407A supplied
with the meter) with
some electrolyte
while shaking it gen-
tly. Refill with clean
electrolyte.
4. Gently tap the sides
of the membrane
with your finger to
ensure that no air
bubbles remain
trapped inside.
To avoid damaging the membrane, do not
tap the membrane directly on the bottom.
5. Place the rubber O-Ring properly inside
the membrane cap.
6. With the sensor facing down, screw the
cap clockwise. Some electrolyte will over-
flow.
When not in use and during polar-
ization, protect the membrane with
the supplied cap.
Shipping
cap
black
red
THEN SCREW
BACK ON
THEN TAP
FILL FIRST
SPECIFICATIONS
Range 0.0 to 19.9 mg/L (ppm)
Resolution 0.1mg/L
Accuracy ±1.5% FS
TypicalEMC ±0.8mg/L
Deviation with 4 m cable probe
Calibration Manual, 1 or 2 point
(zeroandslope)
Temperature Automatic, 0 to 30°C
Compensation (32to86°F)
Probe HI76407/4,polarographic,
with4m(13') cable (included)
Battery Type 4 x 1.5V AA
Life approx.500hoursofuse
Environment 0 to 50°C (32 to 122°F);
RHmax 100%
Dimensions 196 x 80 x 60 mm
(7.7 x 3.1 x 2.4")
Weight 500 g (1.1 lb.)

89
ZEROCALIBRATION
•DiptheprobeintoHI7040zero
oxygensolutionandstirgen-
tly for 2-3 minutes.
• Allow 2 minutes for the LCD
readout to stabilize.
• Adjust the zero D.O. calibra-
tion trimmer until the display
reads "0.0".
Note Thezerocalibrationscrew
is located close to the probe
connector.
SLOPECALIBRATION
Itissuggestedtoperformtheslopecalibration
insatured air.
• Rinse the probe in a large amount of clean
water to remove any residual zero oxygen
solution.
• Dry the probe tip and allow a few minutes for
the LCD readout to stabilize.
• Press and hold the CAL key.
• Adjust the slope trimmer on
the top of the meter to read
"100%"ontheLCD(whilestill
holdingtheCALbutton).
NoteTheslopecalibrationscrew
is located farthest from the
probeconnection.
• Release the CAL key and the
LCD will display the value in
ppmofoxygen.
The zero calibration of the HI 9142 is very
stable, therefore this procedure needs only to
be performed whenever the probe is re-
placed.
However, because the slope calibration is
more critical, it is recommended to perform
this procedure every week.
%
CAL
CALIBRATION PROCEDURE
PROBE POLARIZATION
The probe is under polarization with a fixed
voltageofapproximately800mV.
Probepolarization isessential forstable mea-
surements with the same recurring degree of
accuracy.
With the probe properly polarized, oxygen is
continually"consumed"bypassingthroughthe
sensitivediaphragmanddissolvingintheelec-
trolyte solution contained in the probe.
If this operation is interrupted, the electrolyte
solution continues to be enriched with oxygen
untilitreachesanequilibriumwiththesurround-
ingsolution.
Whenevermeasurementsaretakenwithanon-
polarized probe, the oxygen level revealed is
both that of the tested solution as well as that
presentintheelectrolytesolution.Thisreading
is incorrect
Thecalibration isvery simpleand fast.
• Make sure the probe is ready for measure-
ments(seeinitialpreparation at page7),i.e.
themembraneisfilledwithelectrolyteandthe
probe is connected to the meter.
• Switch the meter on by
pressing the ON/OFF key
• Foranaccuratecalibration,
itisrecommendedthatyou
wait at least 15 minutes to
ensure precise condition-
ingoftheprobe.
• Removetheprotectivecap
fromtheD.O.probe.
ON/OFF

10 11
ALTITUDE & SALINITY COMPENSATION
If the sample contains salts or if you are
performing the measurements at a different
altitudethansealevel,thereadoutvaluesmust
be corrected, taking into account the lower
degreeofoxygensolubility.
ALTITUDE COMPENSATION
Allthereadouts are referredatsealevel, thus
the displayed measurements are higher than
theactualvalues. Infact,altitude affects D.O.
concentrationdecreasingitsvalue.Thefollow-
ingtablereportstheoxygensolubilityatvarious
temperaturesandaltitudes,basedonsealevel
barometricpressureof760 mmHg.
This gives an idea of the error that can be
introducedatdifferentaltitudesandallowsyou
to calculate the quantity to be subtracted to
correctyourreading.
TAKING MEASUREMENTS
Makesurethemeterhasbeen
calibrated and the protective
cap has been removed. Im-
mersethetipoftheprobeinthe
sample to be tested.
Make sure the temperature sensor is also
immersed.
Foraccuratedissolvedoxygenmeasurements
awatermovementof0.3m/secisrequiredata
minimum. This is to ensure that the oxygen-
depleted membrane surface is constantly re-
plenished. A moving stream will provide ad-
equatecirculation.Toquicklycheckifthewater
speedissufficient,waitforthereadingtostabi-
lizeandthenmovetheD.O.probe.Ifthereading
is still stable, the measurement conditions are
right, while if the reading increases the water
movementisnotadequate.
Duringfieldmeasurements,thisconditionmay
bemet bymanually agitatingthe probe. Accu-
ratereadingsarenotpossiblewhiletheliquidis
at rest.
Duringlaboratorymeasurements,theuseof a
magnetic stirrer to ensure a certain velocity in
the fluid is recommended. In this way, errors
duetothediffusionoftheoxygenpresentinthe
air in the solution are reduced to a minimum.
Atalltimes,timenecessaryforthermalequilib-
riumtooccurbetweentheprobeandthesample
mustbeallowed(afewminutesfortemperature
differenceofseveraldegrees).
°C
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
32
34
36
38
40
0 m
14.6
13.8
13.1
12.4
11.8
11.3
10.8
10.3
9.9
9.5
9.1
8.7
8.4
8.1
7.8
7.5
7.3
7.1
6.8
6.6
6.4
300 m
14.1
13.3
12.7
12.0
11.4
10.9
10.4
9.9
9.7
9.2
8.8
8.4
8.1
7.8
7.5
7.2
7.1
6.9
6.6
6.4
6.2
600 m
13.6
12.9
12.2
11.6
11.0
10.5
10.1
9.6
9.2
8.7
8.5
8.1
7.8
7.5
7.3
7.0
6.8
6.6
6.3
6.2
6.0
1200 m
12.7
12.0
11.4
10.8
10.3
9.8
9.4
9.0
8.6
8.3
7.9
7.7
7.3
7.0
6.8
6.5
6.4
6.2
5.9
5.7
5.6
1500m
12.3
11.6
11.0
10.4
9.9
9.5
9.1
8.7
8.3
8.0
7.7
7.3
7.1
6.8
6.6
6.3
6.1
6.0
5.7
5.6
5.4
1800m
11.8
11.2
10.6
10.1
9.6
9.2
8.8
8.3
8.0
7.7
7.4
7.1
6.8
6.6
6.3
6.1
5.9
5.8
5.5
5.4
5.2
900 m
13.2
12.4
11.9
11.2
10.6
10.2
9.7
9.3
8.9
8.6
8.2
7.8
7.5
7.3
7.0
6.8
6.6
6.4
6.1
5.9
5.8
Altitude, Meters above Sea Level °F
32.0
35.6
39.2
42.8
46.4
50.0
53.6
57.2
60.8
64.4
68.0
71.6
75.2
78.8
82.4
86.0
89.6
93.2
96.8
100.4
104.4

12 13
PROBE & MEMBRANE MAINTENANCE
The oxygen probe body is made of reinforced
plastic for maximum durability.
Athermistortemperaturesensorprovidestem-
peraturemeasurementandcompensation.When
notinuse,itisalwaysrecommendedtoprotect
the probe against damage and dirt using the
suppliedcap.
To replace the membrane or refill with elec-
trolyte,proceed asfollows:
• Removetheprotectivecap
bygentlytwistingandpull-
ing it off (see fig. 1).
• Unscrew the membrane
by turning it counter-
clock-wise (see fig. 2)
• Wet the sensor by soak-
ingthebottom(2.5cm)of
the probe in HI 7041S
electrolyte solution for 5
minutes.
• Rinsethenewmembrane
(HI76407Asuppliedwith
themeter)withsomeelec-
trolyte while shaking it
gently. Refill with clean
electrolyte.
• Gently tap the sides of
the membrane with your
fingertoensurethatnoair
bubbles remain trapped
inside.Do no directlytap
the bottom as this will
damagethemembrane.
• Makesurethattherubber
O-ringisseatedproperly
insidethemembranecap.
TWIST
AND
PULL
fig. 1
UNSCREW
fig. 2
SALINITY COMPENSATION
The table below shows the influence of salt in
themeasurementofoxygen.
In HI 9142 allthereadoutsarereferredto0g/l
of salinity value. In fact, salinity affects D.O.
concentrationdecreasingitsvalue.
Foryourreferencethetablebelowreportsthe
oxygensolubilityat varioustemperaturesand
salinity. From the table you can calculate the
quantitytobesubtractedtocorrectyourread-
ing.
35 g/l
9.0
8.6
8.3
8.0
7.6
7.4
7.1
6.9
6.6
6.4
30 g/l
9.3
8.9
8.6
8.2
7.9
7.6
7.3
7.1
6.8
6.6
°C
10
12
14
16
18
20
22
24
26
28
0 g/l
11.3
10.8
10.3
9.9
9.5
9.1
8.7
8.4
8.1
7.8
10 g/l
10.6
10.1
9.7
9.3
8.9
8.5
8.2
7.9
7.6
7.4
20 g/l
9.9
9.5
9.1
8.7
8.4
8.0
7.8
7.5
7.2
7.0
°F
50.0
53.6
57.2
60.8
64.4
68.0
71.6
75.2
78.8
82.4
Salinity (g/l) at Sea Level

14 15
BATTERY REPLACEMENT
Whenthebatterylevelislow,
"V" is displayed on the LCD
towarntheuserthatthebat-
tery needs to be replaced.
The meter will still work for approximately 4
hours,thenthedisplaywillbeshut-off to avoid
erroneousreadings.
Battery replacement must only take place in a
safe area and using alkaline 1.5V AA type
batteries.
Inordertoreplacethebatteries,simplyremove
the two screws on the rear cover of the instru-
ment and replace all four batteries with new
ones, while paying attention to the correct
polarity.
V
• With the sensor facing down, screw the
membrane cap clock-wise. Some electro-
lytewilloverflow.
The Platinum cathode (#8 in the Functional
Descriptionatpage4)shouldalwaysbebright
and untarnished. If it is tarnished or stained,
which could be due to contact with certain
gasesorextendedusewithalooseordamaged
membrane, the cathode should be cleaned.
Use a lint-free cardboard or cloth and rub the
cathodeverygentlysidetoside4-5times.This
willbeenoughtopolish andremoveanystains
withoutdamagingtheplatinumtip.Afterwards,
rinsetheprobewithdeionizedordistilledwater
and install a new membrane cap using fresh
electrolyte.Recalibratetheinstrument.
Important:Inordertohaveaccurateandstable
measurements,itisimportantthatthe surface
of the membrane is in perfect condition. This
semi-permeablemembraneisolatesthesensor
elementsfromtheenvironmentbutallowsoxy-
gen to enter. If any dirt is observed on the
membrane,rinsecarefullywithdistilledordeion-
izedwater.Ifanyimperfectionstillexists,orany
damageisevident (such aswrinklesor tears),
themembraneshouldbereplaced.Makesure
thattheO-Ring isproperlyseatedinthemem-
branecap.

16 17
WARRANTY
AllHannaInstrumentsmeters are warranted
fortwoyearsagainstdefectsinworkmanship
and materials when used for their intended
purpose and maintained according to the in-
structions. The probes are warranted for a
period of six months.
Damagesduetoaccidents,misuse,tampering
orlackofprescribedmaintenancearenotcov-
ered. This warranty is limited to repair or re-
placementfreeofcharge.
If service is required, contact the dealer from
whom you purchased the instrument. 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 war-
ranty,youwillbenotifiedofthechargeforrepair
or replacement. If the instrument is to be re-
turned to Hanna Instruments, obtain a Return
Goods Authorization from the Customer Ser-
vice Department first and then send it with
shipment cost prepaid. When shipping any
instrument, make sure it is properly packaged
forcompleteprotection.
Allrightsarereserved.Reproductioninwholeor
inpartisprohibitedwithoutthewrittenconsent
ofthecopyrightowner.
HannaInstrumentsreservestherightto
modifythedesign,constructionandappear-
anceof itsproducts withoutadvance notice.
ACCESSORIES
HI7040M Zerooxygensolution,230 mL
HI7040L Zerooxygensolution,500 mL
HI7041S Refillingelectrolytesolution,
30 mL
HI76407/4 D.O. probe with 4 m (13')
cable
HI76407/10 D.O. probe with 10 m (33')
cable
HI76407/20 D.O. probe with 20 m (66')
cable
HI76407A/P D.O. membrane (5 pcs)

18 19
CE DECLARATION OF CONFORMITY
RecommendationsforUsers
Before using this product, make sure that it is entirely suitable for the environment in
which it is used.
Operation of this instrument in residential area could cause unacceptable interfer-
ences to radio and TV equipments, requiring the operator to take all necessary steps
to correct interferences.
Any variation introduced by the user to the supplied equipment may degrade the
instrument's EMC performance.
To avoid electrical shock, do not use this instrument when voltages at the measure-
ment surface exceed 24 Vac or 60 Vdc.
To avoid damages or burns, do not perform any measurement in microwave ovens.
In particular cases the meter could turn off. In these cases it can be turned on by
pressing the ON/OFF key.

MAN9142R2 08/05
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