User's Manual
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
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.
3. Rinse the membrane (sup-
plied with the meter) with
electrolyte while shaking it
gently. Refill with clean
electrolyte.
4. Gently tap the sides of the
membrane with the finger
tip to ensure that no air
bubbles remain trapped. To
avoid damaging the mem-
brane, do not tap the
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 in-
side 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 solu-
tion. 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 recom-
mended. 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 equilib-
rium 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
2
(rate of Oxygen
saturation with reference to 100% at sea
level). Press the RANGE key to select
the desired range.
The temperature measurement is al-
ways 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).
SALINITY COMPENSATION
To enter salinity compensation, press the FACTOR key
twice and the “SALT FACTOR” message will be dis-
played. Use UP and DOWN keys to set the salinity
between 0 and 80 g/L.
The meter will automatically compensate for salinity ef-
fects (see also following table for verification).
USER MANUAL
PORTABLE
DISSOLVED OXYGEN METER
MODEL: SM605
Dissolved Oxygen Meter
°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
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
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
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
THEN SCREW
BACK ON
THIRD
TAP
SECOND
FILL
FIRST
INSERT
O’RING
Shipping
cap
black
red