Hanna Instruments HI 9142 User manual

1
Instruction Manual
HI 9142
Portable Waterproof
Dissolved Oxygen Meter
www.hannainst.com

2
Dear Customer,
Thank you for choosing a Hanna Instruments Product.
Please read this instruction manual carefully before using the
instrument.
This manual will provide you with all 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.
TABLE OF CONTENTS
PRELIMINARY EXAMINATION............................................... 3
GENERAL DESCRIPTION ...................................................... 3
PROBE FUNCTIONAL DESCRIPTION ...................................... 4
METER FUNCTIONAL DESCRIPTION ..................................... 5
SPECIFICATIONS ................................................................. 6
PROBE INITIAL PREPARATION ............................................. 7
CALIBRATION PROCEDURE .................................................. 9
TAKING MEASUREMENTS ................................................. 11
ALTITUDE AND SALINITY COMPENSATION .......................... 12
PROBE AND MEMBRANE MAINTENANCE ............................ 14
BATTERY REPLACEMENT ................................................... 16
ACCESSORIES ................................................................... 17
WARRANTY...................................................................... 18

3
PRELIMINARY EXAMINATION
Remove the instrument from the packing material and examine it
tomakesurethatnodamagehasoccurredduringshipping.Ifthere
is any damage, notify your Dealer.
The meter is supplied complete with:
•HI 76407/4 DO probe with 4 m cable
••
••
•2 spare membranes with O-rings
•HI 7041S electrolyte solution (30 mL)
•Calibration screwdriver
••
••
•Batteries (3 x 1.5V AAA)
••
••
•Instruction manual
••
••
•Rugged carrying case
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 solves the common
problems of field use, such as cold, rain, snow and dust, that can
damage a meter, rapidly deteriorating its performance and life.
It is very simple to use: calibration is performed with HI 7040 zero
oxygen solution, while 100% calibration is done in air.
The polarographic probe (HI 76407/4) is provided with a
membrane covering the sensors and a built-in thermistor for
temperaturemeasurementandcompensation.Thethinpermeable
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 membrane reacts
causing current to flow, allowing the determination of oxygen.
The probe included with the meter is supplied with a 4 m (13')
cable that allows measurements to be taken even in even hard to
reach places. For applications that require longer probe cables, the
HI 76407/10 and HI 76407/20 probes with a 10 m (33') or 20 m
(67') cable are available.

4
1. D.O. probe
2. Protective cap
3. Shielded cable
4. Polypropylene probe body
5. Temperature sensor
6. O-Ring seal
7. Silver chloride (AgCl) anode
8. Platinum cathode (sensor)
9. Oxygen permeable membrane
10. Membrane cap
PROBE FUNCTIONAL DESCRIPTION
9
1
3
4
4
5
6
7
8
9
2
10
8
7
6

5
METER FUNCTIONAL DESCRIPTION
1. Liquid Crystal Display (LCD)
2. On/Off button
3. °C/°F Celsius or Fahrenheit selection button
4. Zero oxygen calibration button
5. Battery compartment cap
6. Probe connector (DIN7)
7. Calibration button
8. Secondary LCD line
9. Primary LCD line
10. Slope calibration trimmer

6
SPECIFICATIONS
egnaR )mpp(L/gm9.91ot0.0
)F°0.221ot0.32(C°0.05ot0.5-
noituloseR L/gm1.0
)F°1(C°1.0
ycaruccA
SF%5.1±
)F°1±(C°2.0±
rorreeborpgnidulcxe
noitarbilaC OD%001nilaunaM
OD%0nicitamotuA
erutarepmeT
noitasnepmoC
C°05ot0,citamotuA
)F°221ot23(
eborP 4/70467IH ,cihpargoralop,
)dedulcni(elbac)'31(m4htiw
epyTyrettaB AAAV5.1x3
efiLyrettaB esufosruoh0001.xorppA
ffo-otuA setunim03.xorpparetfA
tnemnorivnE ;)F°221ot23(C°05ot0
%001xamHR
snoisnemiD mm63x27x581
)"4.1x8.2x3.7(
thgieW ).zo6.01(g003

7
PROBE INITIAL PREPARATION
Probe Preparation
All D.O. probes from Hanna Instrument are shipped dry. To
hydrate the probe and prepare it for use, connect it to the
meter and proceed as follows.
1. Remove the red & black plastic cap. This
cap is used for shipping 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 gently. 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 overflow.
When not in use and during polarization, protect
the membrane with the supplied cap.
Shipping
cap
black
red
THEN SCREW
BACK ON
THEN TAP
FILL FIRST

8
Connect the probe to the instrument.
Turn the instrument ON by pressing
On/Off.
At start-up the display will show
all the used segments for a
few seconds followed by the
percentage indication of the
remaining battery life.
•After a few seconds “Cnd
Prb” message appears, to
inform the user that the
probe is in auto-conditioning
mode (automatic polarization,
about 1 minute).
Note:Press any key (except On/Off) to skip conditioning
time.
•When the conditioning message disappears, the probe is
polarized and the instrument can be calibrated.
•The meter is now ready to operate.
If the probe is not connected, the display shows “---“ on both
LCD lines.
The auto-off feature turns the instrument off after about
30 minutes, if no key is pressed.

9
PROBE POLARIZATION
The probe is under polarization with a fixed voltage of
approximately 800 mV.
Probe polarization is essential for stable measurements with the
same recurring degree of accuracy.
With the probe properly polarized, oxygen is continually
“consumed“ by passing through the sensitive diaphragm and
dissolving in the electrolyte solution contained in the probe.
If this operation is interrupted, the electrolyte solution continues
to be enriched with oxygen until it reaches an equilibrium with the
surrounding solution.
Whenevermeasurementsaretakenwithanon-polarizedprobe,the
oxygen level revealed are both that of the tested solution as well
of the electrolyte solution. This reading is incorrect.
CALIBRATION PROCEDURE
The calibration is very simple and fast.
•Make sure the probe is ready for measurements (see initial
preparation at page 7), i.e. the membrane is filled with
electrolyte and the probe is connected to the meter.
•Switch the meter on by pressing the On/Off
key.
•Foranaccuratecalibration,itisrecommended
thatyou wait at least 15 minutes to ensure
precise conditioning of the probe.
•Remove the protective cap from the D.O.
probe.

10
SLOPE CALIBRATION
It is suggested to perform the slope calibration in saturated air
(100% DO).
•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 the CAL key and follow the
indication on the display.
•Adjust the slope trimmer on the bottom
ofthemetertoread“100%“ontheLCD.
Note:
•The slope calibration screw is located on
the bottom of the case.
•Press the CAL key and the LCD will
display the value in mg/L of oxygen.
A zero calibration is also possible.
ZERO CALIBRATION
•Dip the probe into HI 7040 zero oxygen
solution and stir gently for 2-3 minutes.
•Press and hold down CAL key then press
ZERO key.
• % tag will blink until the reading stabilize.
•When the reading is stable, the message “Press CAL, ...., meter
is calibrated“ will be displayed.
•Press CAL to exit zero calibration.
The zero calibration of the HI 9142 is very stable, therefore this
procedure needs only to be performed whenever the probe is
replaced.
However, because the slope calibration is more critical, it is
recommended to perform this procedure every week.