Milwaukee Instruments SM605 User Manual
USER MANUAL
PORTABLE
DISSOLVED OXYGEN METER
MODEL: SM605
Dissolved Oxygen Meter
WARRANTY:
This instrument is warranted against all defects in
materials and manufacturing for a period of two years
from the date of purchase. Probe is warranted for six
months.
If during this period the repair or replacement of parts
is required, and the damage is not because of negligence
or erroneous operation by the user, please return the
parts to either distributor or our office and the repair will
be made free of charge.
Damage due to accident, misuse, tampering or lack of
prescribed maintenance are not covered.
Note: We reserve the right to modify the design,
construction and appearance of our products
without advance notification.
INITIAL OPERATIONS
The meter is supplied with a 9V battery. Remove the
battery compartment cover on the back of the meter and
install the battery while paying attention to its polarity.
PROBE PREPARATION
D.O. probes 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 and black plastic cap.
This cap is used for shipping purposes
Shipping
cap
only and can be thrown away.
2. Wet the sensor by soaking the bottom
2.5 cm of the probe in electrolyte
(MA9071) for 5 minutes.
black
red
3. Rinse the membrane (supplied with the meter) with
electrolyte while shaking it
gently. Refill with clean
electrolyte.
4. Gently tap the sides of the
membrane with the finger
SECOND
FILL
THIRD
TAP
FIRST
INSERT
O’RING
tip to ensure that no air
bubbles remain trapped. To
avoid damaging the membrane, do not tap the
THEN SCREW
BACK ON
membrane directly on the
bottom.
5. Place 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, place the
protective cap supplied with the meter.
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 inside 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 non-polarized
probe, the oxygen level indicated is both that of the test
solution as well as that present in the electrolyte solution. This reading is obviously incorrect.
MEASUREMENTS
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 while ensuring that also the
temperature sensor is immersed.
For accurate dissolved oxygen measurements, a water
movement of at least 0.3 m/sec is required. This is to
ensure that the oxygen-depleted membrane surface is
constantly replenished. A moving stream will provide an
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 remains 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.
Anyway, wait the time necessary for thermal equilibrium to occur between the probe and the sample (a few
minutes for temperature difference of several degrees).
The meter can display D.O. readings in
mg/L (ppm) and in % O
saturation with reference to 100% at sea
(rate of Oxygen
2
level). Press the RANGE key to select
the desired range.
The temperature measurement is always displayed on the lower part of
the LCD.
If the sample contains salts or if the measurement is
performed at altitude different from sea level, the readout
values must be corrected, taking into account the lower
degree of oxygen solubility.
Set altitude and salinity compensations before performing
calibration and taking measurements. The meter will
automatically compensate for these factors.
ALTITUDE COMPENSATION
To enter altitude compensation, press the FACTOR key
and the meter will display the “ALT FACTOR” message.
Use UP and DOWN keys to set the altitude from 0 to
4.0 km, in steps of 0.1 km.
The meter will automatically compensate for altitude (see
also the table below for verification).
Altitude, Meters above Sea Level
°C
0
m
0
14.6
2
13.8
4
13.1
6
12.4
8
11.8
10
11.3
12
10.8
14
10.3
16
9.9
18
9.5
20
9.1
22
8.7
24
8.4
26
8.1
28
7.8
30
7.5
32
7.3
34
7.1
36
6.8
38
6.6
40
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
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
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
1500
m
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
1800
m
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
SALINITY COMPENSATION
To enter salinity compensation, press the FACTOR key
twice and the “SALT FACTOR” message will be displayed. Use UP and DOWN keys to set the salinity
between 0 and 80 g/L.
The meter will automatically compensate for salinity effects (see also following table for verification).
Salinity (g/l) at Sea Level
35 g/l
°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
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
CALIBRATION PROCEDURE
Calibration is simple and is recommended every time the
meter is switched on.
• Make sure the probe is ready for measurements (see
Probe Preparation), i.e. the membrane is filled with
electrolyte and the probe is connected to the meter
and properly polarized.
• Switch the meter on by pressing the
ON/OFF key.
• The "COND" message will be displayed for about 45 seconds to inform
the user that the probe is in autoconditioning mode (automatic
polarization) .
• Once “COND” disappears, the probe
is polarized and the instrument can
be calibrated.
• Remove the protective cap from the
D.O. probe.
• Press CAL. "----" appears on the
larger LCD together with "CAL" to
indicate that the instrument is in calibration mode.
• The instrument will automatically standardize itself to the actual saturation
value. After approx. 1 minute it will
display "100%" to indicate that the
calibration is complete.
Notes:
• It is recommended to re-calibrate the meter when-
ever probe, membrane or electrolyte is changed.
• To exit the calibration mode, press CAL.
• Switching from readings in % O
mg/L does not require recalibration.
to readings in
2
PROBE & MEMBRANE MAINTENANCE
The D.O. probe body is made of reinforced plastic for
maximum durability.
A thermistor temperature sensor provides temperature
measurements of the tested sample. It is always recommended to keep the protective cap on the probe when
not in use, to protect it against damage and dirt.
To replace the membrane or refill it with electrolyte,
proceed as follows:
• Remove the protective cap by gently twisting and pulling it off the probe's
body.
• Unscrew the membrane by turning it
counterclockwise with the other hand.
TWIST
AND
PULL
• Wet the sensor by soaking the bottom 2.5 cm of the probe in electrolyte
(MA9071) for 5 minutes.
• Rinse the new membrane supplied
with the meter with electrolyte, while
shaking it gently. Refill with clean
electrolyte.
• Gently tap the sides of the membrane with the finger tip to ensure
that no air bubbles remain trapped.
Do no directly tap the bottom with
the finger as this will damage the
UNSCREW
membrane.
• Make sure that the rubber
O-ring is seated properly
inside the membrane cap.
• With the sensor facing
down, screw the membrane cap clockwise.
Some electrolyte will overflow.
If the Platinum cathode is tarnished or stained, which
could be due to contact with certain gases or to an
extended use with a loose or damaged membrane, it
should be cleaned. Use a clean lint-free cardboard or
cloth and rub the cathode very gently side to side 4-5
times. This will be enough to polish it 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 and follow the steps above. Recalibrate the
instrument.
Note: To obtain accurate and stable measurements, it is
important that the surface of the membrane be in
perfect condition. This semipermeable membrane
isolates the sensor elements from the environment, but allows oxygen to enter. If any dirt is
observed on the membrane, rinse it carefully with
distilled or deionized water. If any imperfections
still exist, or any damage is evident (such as
wrinkles or tears-holes), replace the membrane.
Make sure that the O-Ring is properly seated in
the membrane cap.
Note: If don’t take measurements for a few hours,
protect the probe with the supplied cap.
BATTERY REPLACEMENT
When the battery becomes weak, the
meter will display the blinking battery
symbol.
When the low battery indicator appears, only about 10 hours
of battery life remain. A low battery will result in unreliable
measurements. It is recommended to replace the battery
immediately.
Battery replacement must only take place in a non-hazardous area using an alkaline 9V battery.
Turn the meter off, unscrew the two
screws on the rear of the instrument,
remove the cover and replace the 9V
battery with a new one. Install the battery while paying attention to its polarity
and reattach the cover.
ACCESSORIES:
MA840 D.O. probe
MA841 Spare membrane, 5 pcs
MA9071 Refilling Electrolyte solution, 230 ml
SPECIFICATIONS:
RANGE 0.0 to 45.00 mg/L (ppm) O
0.0 to 300 % O
0.0 to 50.0 °C
2
RESOLUTION 0.01 mg/L (ppm) O
0.1 %O
2
0.1 °C
2
2
ACCURACY (@25°C)
± 1.5% Full Scale mg/L (ppm) O
± 1.5% Full Scale %O
± 0.5 °C
2
TYPICAL EMC DEVIATION
± 0.3 mg/L (ppm) O
± 3.5 %O
± 0.5 °C
2
2
CALIBRATION Automatic in saturated air
TEMPERATURE COMPENSATION
Automatic, from 0 to 50°C
ALTITUDE COMPENSATION
0 to 4000 m; 100 m resolution
SALINITY COMPENSATION
0 to 80 g/L; 1 g/L resolution
PROBE MA840 (included)
ENVIRONMENT 0 to 50°C; 100% RH max.
BATTERY TYPE 1 x 9V alkaline (included)
BATTERY LIFE approx. 100 hours of use
AUTO-OFF after 4 hours of non-use
DIMENSIONS 200 × 85 × 50 mm
WEIGHT 280 g (with battery)
ISM605R1 11/03
2
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