Chapter 6
RDO/DO Measurement Module
Thermo Scientific
Orion Versa Star Pro Meter User Manual
89
5.
Wait for the dissolved oxygen value on the meter to stabilize and perform one of the
following actions:
a.
Press the f2 (Accept) key to accept the displayed value.
or
b.
Press the f3 (Edit) key and use the numeric keypad to enter the dissolved oxygen
value of the calibration solution. Press the f2 (Accept) key to confirm the entered value.
6.
Press the f3 (Cal Done) key to save and end the calibration.
7.
The meter will display the calibration summary and export the data to the calibration log.
Press the measure (esc) key to proceed to the measurement mode.
Set Zero Calibration
A Water Saturated Air calibration or Air Saturated Water calibration must be completed before a
Set Zero calibration can be performed.
Prepare a sodium sulfite solution by dissolving about 15.0 grams of Na
2
SO
3
in about 250 mL of
distilled water. Transfer the solution to a BOD bottle or flask and use plastic paraffin film to seal
the bottle. A small amount of cobalt salt can be added to the sodium sulfite solution to act as an
indicator and change color when the sodium sulfite solution no longer has zero oxygen content.
1.
Press the f1 (Cal) key to start the calibration.
a.
If more than one channel is displayed in the measurement mode, press the
or
key to highlight the desired channel and press the f3 (Select) key.
2.
Press the ▲ or ▼ key to highlight Set Zero and press the f3 (Select) key.
3.
Prepare the DO probe and zero oxygen solution and allow them to reach equilibrium.
a.
Use plastic paraffin film to seal the open area between the DO probe and vessel
containing the calibration solution.
4.
When the DO probe and calibration apparatus are ready, press the f3 (Start) key.
a.
If using a stirrer probe, the stirrer probe will start stirring when the f3 (Start) key is
pressed and stop stirring when the reading stabilizes.
5.
Wait for the dissolved oxygen value on the meter to stabilize and press the f2 (Accept)
key.
a.
0.0 % will be displayed when the reading stabilizes.
6.
Press the f3 (Cal Done) key to save and end the calibration.
7.
The meter will display the calibration summary and export the data to the calibration log.
Press the measure (esc) key to proceed to the measurement mode.
