Dissolved Oxygen Transmitter
Calibration Correction
Teledyne Analytical Instruments
31
Calibration Correction Factors
5.1 Calibration Correction Factors
Temperature, relative humidity, elevation and salinity factors affect
the solubility of oxygen in a liquid and thus affect the accuracy of the
dissolved oxygen calibration using the air calibration method. The affect
on solubility is caused by barometric pressure changes due to changes in
the atmospheric environment. Because the dissolved oxygen sensor
responds to pressure changes, the output of the sensor will be affected
by these pressure variations. To correct for these factors, refer to the
tables below.
Please note that the tables only apply to absolute dissolved oxygen
measurements (those in ppm or mg/l and not to relative dissolved
oxygen measurements (typically expressed as percent oxygen). The data
is used when performing an
air span calibration
or an
air saturated
sample calibration.
To compensate for these effects, use the following procedure:
1.
Determine the temperature of the air (if the electrode is being
calibrated in air only) or the temperature of the air saturated
sample (if the electrode is being calibrated in solution).
2.
Refer to Table 5-1, Oxygen Saturation vs. Temperature and find
the solubility value of oxygen in ppm for that temperature.
Interpolation may be necessary if the temperature is between the
listed values. Record this value.
