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SDL150-EU-EN-V2.1-11/11
Taking Dissolved Oxygen Measurements
1. Immerse the DO probe into the solution under test to a depth of at least 10cm. The depth
specification is important since the temperature measurement of the solution and the automatic
temperature compensation circuitry rely on the probe depth to operate correctly.
2. Allow the test to stabilize for several minutes to achieve thermal equilibrium between the probe
and measurement sample.
3. To successfully measure DO the velocity of the solution striking the probe must be at least 0.2-
0.3m/s (meters per second); if not, simply agitate the solution with the probe while waiting for
thermal equilibrium to be achieved.
4. In laboratory environments use of a magnetic agitator to ensure proper velocity is
recommended. In this way, errors due to the diffusion of the oxygen present in the surrounding
air are minimized.
5. The Dissolved Oxygen measurements are displayed on the upper, larger digit display area of
the meter’s LCD. Measurements outside of the specified range will yield dashes (- - -).
Temperature measurements are displayed in the range of 0 to 50
o
C (32 to 122
o
F) on the lower
LCD line in smaller sized digits.
6. %SALT, Altitude (height) compensation, temperature units of measure, and other parameters,
can be modified in the SETUP mode (refer to the SETUP mode section later in this guide).
Taking Oxygen in Air Measurements
1. The probe measures Oxygen in the air surrounding the probe (in percent).
2. The meter defaults to the DO measurement mode. Therefore, press and hold the FUNCTION
button for 1.5 seconds to switch to the %O2 mode (oxygen in air). The displayed unit of
measure will switch from mg/L to 02. To return to the DO measurement mode simply press and
hold the FUNCTION button again for 1.5 seconds.
3. The Oxygen in Air measurements are displayed on the upper, larger digit display area of the
meter’s LCD. Measurements outside of the specified range will yield dashes (- - -). Temperature
measurements are displayed in the range of 0 to 50
o
C (32 to 122
o
F) on the lower LCD line in
smaller sized digits.
