Instruction Manual
HI 9142
Portable Waterproof
Dissolved Oxygen Meter
www.hannainst.com
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 neces-
sary information for the correct use of the
instrument.
If you need additional technical information, do
not hesitate to e-mail us at
tech@hannainst.com
This instrument is in compliance with the CE
directives.
PRELIMINARY EXAMINATION
Remove the instrument from the packing material
and examine it to make sure that no damage
has occurred during shipping. If there 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 (4 x 1.5V AA)
• 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.
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 .................................. 8
Taking Measurements............................... 10
Altitude and Salinity Compensation........... 1 1
Probe & Membrane Maintenance .............. 13
Battery Replacement ................................ 15
Accessories.............................................. 16
Warranty ................................................... 17
CE Declaration of Conformity .................... 18
2
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 pro-
vided with a membrane covering the sensors
and a built-in thermistor for temperature measurement and compensation. The thin permeable 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.
3
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.
PROBE FUNCTIONAL DESCRIPTION
3
1
4
6
7
8
METER FUNCTIONAL DESCRIPTION
9
4
5
6
7
8
9
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
4
2
10
1. Battery compartment
2. Probe connector
3. Liquid Crystal Display
4. ON/OFF button
5. Calibration button
6. Slope calibration trimmer
7. Zero oxygen calibration trimmer
5
SPECIFICATIONS
Range 0.0 to 19.9 mg/L (ppm)
Resolution 0.1 mg/L
Accuracy ±1.5% FS
Typical EMC ±0.8 mg/L
Deviation with 4 m cable probe
Calibration Manual, 1 or 2 point
(zero and slope)
Temperature Automatic, 0 to 30°C
Compensation (32 to 86°F)
Probe HI 76407/4, polarographic,
with 4 m (13') cable (included)
Battery Type 4 x 1.5V AA
Life approx. 500 hours of use
Environment 0 to 50°C (32 to 122°F);
RH max 100%
Dimensions 196 x 80 x 60 mm
(7.7 x 3.1 x 2.4")
Weight 500 g (1.1 lb.)
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 ship-
Shipping
cap
ping purposes only and can be
thrown away.
2. Wet the sensor by soaking the
black
bottom (2.5 cm/1") of the probe
in HI 7041S electrolyte solution
red
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
FILL FIRST
THEN TAP
of the membrane
with your finger to
ensure that no air
bubbles remain
trapped inside.
THEN SCREW
BACK ON
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.
6
7
CALIBRATION PROCEDURE
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.
Whenever measurements are taken with a nonpolarized probe, the oxygen level revealed is
both that of the tested solution as well as that
present in the electrolyte solution. This reading
is incorrect
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
ON/OFF
• For an accurate calibration,
it is recommended that you
wait at least 15 minutes to
ensure precise conditioning of the probe.
• Remove the protective cap
from the D.O. probe.
8
ZERO CALIBRATION
• Dip the probe into HI 7040 zero
oxygen solution and stir gently for 2-3 minutes.
• Allow 2 minutes for the LCD
readout to stabilize.
• Adjust the zero D.O. calibration trimmer until the display
reads "0.0".
Note The zero calibration screw
is located close to the probe
connector.
SLOPE CALIBRATION
It is suggested to perform the slope calibration
in satured 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
CAL
the top of the meter to read
"100%" on the LCD (while still
holding the CAL button).
Note The slope calibration screw
is located farthest from the
probe connection.
• Release the CAL key and the
LCD will display the value in
%
ppm of oxygen.
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.
9
TAKING MEASUREMENTS
ALTITUDE & SALINITY COMPENSATION
Make sure the meter has been
calibrated and the protective
cap has been removed. Immerse the tip of the probe in the
sample to be tested.
Make sure the temperature sensor is also
immersed.
For accurate dissolved oxygen measurements
a water movement of 0.3 m/sec is required at a
minimum. This is to ensure that the oxygendepleted membrane surface is constantly replenished. A moving stream will provide adequate circulation. To quickly check if the water
speed is sufficient, wait for the reading to stabilize and then move the D.O. probe. If the reading
is still stable, the measurement conditions are
right, while if the reading increases the water
movement is not adequate.
During field measurements, this condition may
be met by manually agitating the probe. Accurate readings are not possible while the liquid is
at rest.
During laboratory measurements, the use of a
magnetic stirrer to ensure a certain velocity in
the fluid is recommended. In this way, errors
due to the diffusion of the oxygen present in the
air in the solution are reduced to a minimum.
At all times, time necessary for thermal equilibrium to occur between the probe and the sample
must be allowed (a few minutes for temperature
difference of several degrees).
If the sample contains salts or if you are
performing the measurements at a different
altitude than sea level, the readout values must
be corrected, taking into account the lower
degree of oxygen solubility.
ALTITUDE COMPENSATION
All the readouts are referred at sea level, thus
the displayed measurements are higher than
the actual values. In fact, altitude affects D.O.
concentration decreasing its value. The following table reports the oxygen solubility at various
temperatures and altitudes, based on sea level
barometric pressure of 760 mm Hg.
Altitude, Meters above Sea Level
°C
0 m
300 m
10
12
14
16
18
20
22
24
26
28
30
32
34
36
38
40
600 m
0
14.6
14.1
2
13.8
4
13.1
6
12.4
8
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
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
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
6.4
6.1
5.9
5.8
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
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
°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
10
This gives an idea of the error that can be
introduced at different altitudes and allows you
to calculate the quantity to be subtracted to
correct your reading.
11
SALINITY COMPENSATION
The table below shows the influence of salt in
the measurement of oxygen.
In HI 9142 all the readouts are referred to 0 g/l
of salinity value. In fact, salinity affects D.O.
concentration decreasing its value.
For your reference the table below reports the
oxygen solubility at various temperatures and
salinity. From the table you can calculate the
quantity to be subtracted to correct your reading.
Salinity (g/l) at Sea Level
°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
30 g/l
9.3
8.9
8.6
8.2
7.9
7.6
7.3
7.1
6.8
6.6
35 g/l
9.0
8.6
8.3
8.0
7.6
7.4
7.1
6.9
6.6
6.4
°F
50.0
53.6
57.2
60.8
64.4
68.0
71.6
75.2
78.8
82.4
PROBE & MEMBRANE MAINTENANCE
The oxygen probe body is made of reinforced
plastic for maximum durability.
A thermistor temperature sensor provides temperature measurement and compensation. When
not in use, it is always recommended to protect
the probe against damage and dirt using the
supplied cap.
To replace the membrane or refill with electrolyte, proceed as follows:
• Remove the protective cap
by gently twisting and pulling it off (see fig. 1).
• Unscrew the membrane
by turning it counterclock-wise (see fig. 2)
TWIST
AND
PULL
• Wet the sensor by soak-
ing the bottom (2.5 cm) of
fig. 1
the probe in HI 7041S
electrolyte solution for 5
minutes.
• Rinse the new membrane
(HI 76407A supplied with
the meter) with some electrolyte while shaking it
gently. Refill with clean
electrolyte.
• Gently tap the sides of
the membrane with your
finger to ensure that no air
bubbles remain trapped
inside. Do no directly tap
the bottom as this will
damage the membrane.
• Make sure that the rubber
O-ring is seated properly
UNSCREW
inside the membrane cap.
fig. 2
12
13
• With the sensor facing down, screw the
membrane cap clock-wise. Some electrolyte will overflow.
The Platinum cathode (#8 in the Functional
Description at page 4) should always be bright
and untarnished. If it is tarnished or stained,
which could be due to contact with certain
gases or extended use with a loose or damaged
membrane, the cathode should be cleaned.
Use a lint-free cardboard or cloth and rub the
cathode very gently side to side 4-5 times. This
will be enough to polish and remove any stains
without damaging the platinum tip. Afterwards,
rinse the probe with deionized or distilled water
and install a new membrane cap using fresh
electrolyte. Recalibrate the instrument.
Important: In order to have accurate and stable
measurements, it is important that the surface
of the membrane is in perfect condition. This
semi-permeable membrane isolates the sensor
elements from the environment but allows oxygen to enter. If any dirt is observed on the
membrane, rinse carefully with distilled or deionized water. If any imperfection still exists, or any
damage is evident (such as wrinkles or tears),
the membrane should be replaced. Make sure
that the O-Ring is properly seated in the membrane cap.
BATTERY REPLACEMENT
When the battery level is low,
"V" is displayed on the LCD
V
to warn the user that the battery needs to be replaced.
The meter will still work for approximately 4
hours, then the display will be shut-off to avoid
erroneous readings.
Battery replacement must only take place in a
safe area and using alkaline 1.5V AA type
batteries.
In order to replace the batteries, simply remove
the two screws on the rear cover of the instrument and replace all four batteries with new
ones, while paying attention to the correct
polarity.
14
15
ACCESSORIES
WARRANTY
HI 7040M Zero oxygen solution, 230 mL
HI 7040L Zero oxygen solution, 500 mL
HI 7041S Refilling electrolyte solution,
30 mL
HI 76407/4 D.O. probe with 4 m (13')
cable
HI 76407/10 D.O. probe with 10 m (33')
cable
HI 76407/20 D.O. probe with 20 m (66')
cable
HI 76407A/P D.O. membrane (5 pcs)
All Hanna Instruments meters are warranted
for two years against defects in workmanship
and materials when used for their intended
purpose and maintained according to the instructions. The probes are warranted for a
period of six months.
Damages due to accidents, misuse, tampering
or lack of prescribed maintenance are not covered. This warranty is limited to repair or replacement free of charge.
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 warranty, you will be notified of the charge for repair
or replacement. If the instrument is to be returned to Hanna Instruments, obtain a Return
Goods Authorization from the Customer Service Department first and then send it with
shipment cost prepaid. When shipping any
instrument, make sure it is properly packaged
for complete protection.
16
All rights are reserved. Reproduction in whole or
in part is prohibited without the written consent
of the copyright owner.
Hanna Instruments reserves the right to
modify the design, construction and appearance of its products without advance notice.
17
CE DECLARATION OF CONFORMITY
Recommendations for Users
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 interferences 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 measurement 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.
18
19
SALES & TECHNICAL SERVICE CONTACTS
Australia:
Tel. (03) 9769.0666 • Fax (03) 9769.0699
China:
Tel. (10) 88570068 • Fax (10) 88570060
Egypt:
Tel. & Fax (02) 2758.683
Germany:
Tel. (07851) 9129-0 • Fax (07851) 9129-99
Greece:
Tel. (210) 823.5192 • Fax (210) 884.0210
Indonesia:
Tel. (21) 4584.2941 • Fax (21) 4584.2942
Japan:
Tel. (03) 3258.9565 • Fax (03) 3258.9567
Korea:
Tel. (02) 2278.5147 • Fax (02) 2264.1729
Malaysia:
Tel. (603) 5638.9940 • Fax (603) 5638.9829
Singapore:
Tel. 6296.7118 • Fax 6291.6906
South Africa:
Tel. (011) 615.6076 • Fax (011) 615.8582
Taiwan:
Tel. 886.2.2739.3014 • Fax 886.2.2739.2983
Thailand:
Tel. 66.2619.0708 • Fax 66.2619.0061
United Kingdom:
Tel. (01525) 850.855 • Fax (01525) 853.668
USA:
Tel. (401) 765.7500 • Fax (401) 765.7575
For e-mail contacts and complete list of Sales and
Technical offices, please see www.hannainst.com
MAN9142R2 08/05
Loading...