8
5.
Plug the probe plug into the DO probe socket
at the top of the DOH-SD1.
6.
Power on the instrument
by pressing the POWER button on the front panel once.
(Powering the unit through a 9V AC/DC adapter—an optional accessory—disables the
POWER button.)
7.
Press the
▼
button
(which has the word “Function” stenciled above it) once; the display
will then show “%O
2
” instead of “mg/L”.
8.
Wait at least five minutes
until the display readings stabilize.
9.
Use two fingers to press the REC/ENTER and HOLD/ESC buttons
at the same time.
Release your fingers
once the display shows the following (indicating that air typically
has an oxygen content of 20.9%):
20.9
CAL
10.
Press the REC/ENTER button
. The display will then count down from 30 seconds to 0.
When the countdown is complete, press the Function
▼
button once to return to the
normal display of “mg/L”
Normal operation
1.
To measure the percentage of oxygen dissolved in a liquid
:
•
Make sure that the probe is full fresh electrolyte and has been calibrated recently.
•
Remove the protective cover from the probe head.
•
Plug the probe plug into the DO probe socket at the top of the instrument.
•
Power on the DOH-SD1 by pressing the POWER button on the front panel once.
•
Insert the probe at least 4 inches (10 cm) into the liquid to be measured.
•
Wait a few minutes for the instrument to automatically compensate for any difference
in temperature between the probe and the liquid.
•
Read the DO content of the liquid in mg/L on the upper display and its temperature
on the lower display.
•
Rinse the probe head with tap water after each measurement.
•
Replace the probe head protection cover.
2.
To measure the oxygen content of a volume of air
, first make sure that the oxygen
probe is full of fresh electrolyte, calibrated and correctly inserted, and that the meter is
powered on. Then press the
▼
button (which has the word “Function” stenciled above it)
to make the display show “%O
2
” instead of “mg/L”. Wait at least five minutes until the
readings stabilize. To return to “mg/L” readings, press the
▼
button again.
Whenever the DOH-SD1 is in measurement mode, you can turn off the backlight (which is on by
default) by briefly pressing (but not holding) the POWER/ESC button. To reactivate the
backlight, briefly press the button again.
A DO measurement tip
Agitating the liquid reduces the effect and measurement errors caused by oxygen
diffusing into the liquid from ambient air. At a minimum, this can be done by
shaking the probe while it is immersed. To minimize measurement errors of this
type, Omega recommends using a magnetic agitator, especially in laboratory
settings.
