Reference

Calibration Principle

When the temperature is fixed, the voltage is linearly related to the dissolved oxygen concentration. Due to the slight differences in the production of the probe, the voltage corresponding to the saturated dissolved oxygen needs to be calibrated before accurate data can be obtained.

Saturated dissolved oxygen is greatly affected by temperature changes. In order to improve accuracy, it is necessary to consider changes in dissolved oxygen and saturation voltage caused by temperature changes.

The approximate relationship between saturation voltage and temperature is shown in the following figure. It is necessary to measure the saturated dissolved oxygen voltage at two different temperatures to obtain a temperature compensation curve.

The correspondence between the temperature and saturated dissolved oxygen at standard atmospheric pressure is known, and the saturated oxygen concentration and corresponding voltage at the current temperature can be determined by measuring the temperature to calculate the dissolved oxygen.