Orion Star A223 and Star A323 Portable RDO/DO Meters
4
RDO/DO Calibration
Polarographic DO probes only - A polarographic DO probe must be polarized. The probe is continuously
polarized when it is connected to the meter. If the probe is not connected to the meter: connect the probe to
the meter, connect the meter to a power source and wait 30 to 60 minutes for polarization.
The Orion Star A223 an Star A323 RDO/DO meters can perform a calibration using water-saturated air
(
Air
), air-saturated water (
Water
), Winkler titration (
Manual
) or zero point calibration (
Set Zero
). See the
reference guide for detailed instructions for each calibration.
Air Calibration
1. In the measurement mode, press
f1 (cal)
.
2. Press
or
to highlight
Air
and press
f3 (select)
.
3. Rinse the RDO optical DO probe or polarographic DO probe with distilled water, blot dry with a lint-free
tissue and place into the prepared calibration sleeve or BOD bottle. Allow the probe and water-saturated
air to reach equilibrium.
4. When the probe and water-saturated air are ready, press
f3 (start)
.
5. Wait for the dissolved oxygen reading on the meter to stabilize and stop flashing. Once the reading is
stable, the meter will display
Accepting Auto % Sat. Calibration
and
100.0 %
if using an RDO optical
DO probe or
102.3 %
if using a polarographic DO probe.
6. Press
f3 (cal done)
to export the data to the calibration log or press
f2 (print)
to export the data to the
calibration log and a printer or computer. The meter will proceed to the measurement mode.
Set Zero Calibration
A zero point calibration is performed in an oxygen-free solution. A zero point calibration is not generally
required unless measurements will be taken below 10% saturation or 1 mg/L. Perform an air or water
calibration before performing a zero point calibration.
1. In the measurement mode, press
f1 (cal)
.
2. Press
or
to highlight
Set Zero
and press
f3 (select)
.
3. Rinse the RDO optical DO probe or polarographic DO probe and any other electrodes in use with distilled
water, blot dry with a lint-free tissue and place into the prepared zero oxygen standard. Allow the probe
and standard to reach equilibrium.
4. When the probe and zero oxygen standard are ready, press
f3 (start)
.
5. Wait for the dissolved oxygen reading on the meter to stabilize and stop flashing. Once the reading is
stable, the meter will display
Accepting Auto % Sat. Calibration
and
0.00
.
6. Press
f3 (cal done)
to export the data to the calibration log or press
f2 (print)
to export the data to the
calibration log and a printer or computer. The meter will proceed to the measurement mode.
