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January 2009 UDA2182 Universal Dual Analyzer Product Manual 169
Calibrating a Dissolved Oxygen Probe Using Sample Calibration Method
Introduction
Sample calibration allows a calibration based on a known dissolved oxygen concentration.
It is similar to air calibration except that the known DO value may be entered. Assuming
an accurate reference is available, use the sample calibration method rather than air
calibration if any of the following conditions apply:
• The air is below freezing (32°F, 0°C), or hot (above 104°F, 40°C) or very dry (below
20% relative humidity).
• The probe is mounted such that it is much easier to measure the concentration of the
DO in the water independently than to expose the probe to air. Such mounting is not
recommended but is sometimes necessary.
• The measurement interruption for air calibration cannot be tolerated.
Sample calibration is usually executed by leaving the probe in the measured sample and
adjusting the analyzer to agree with the sample dissolved oxygen measured with a
properly calibrated portable dissolved oxygen meter whose probe is held very close to the
probe of the analyzer. Alternatively, the probe may be removed from the measured sample
and placed in a sample of known dissolved oxygen concentration.
Procedure
Table 8-12 Calibrating a Dissolved Oxygen Probe Using Sample Calibration
Method
Step Action Screen
1
Power the probe for at least
one hour. (power the probe for
24 hours if initial installation)
2
Press
Calibrate
CALIBRATION
Input Temp Cal
Output Cal
Cal History
Input PV Cal
CALIBRATION
Input Temp Cal
Output Cal
Cal History
Input PV Cal
3
Press
Enter
PV INPUT CAL
In 1 DO Cal
PV INPUT CAL
In 1 DO Cal
Use
to select
Input 1 or 2 DO Cal