The FST 100-DO202A Dissolved Oxygen Sensor is an integrated online fluorescence dissolved oxygen sensor designed based on the quenching principle of excited fluorescence by specific substances in physics. When the excitation light shines on the fluorescent substance on the surface of the fluorescent membrane head, the fluorescent substance is excited and emits fluorescence. The extinguishing time of the fluorescence is affected by the concentration of oxygen molecules on the surface of the fluorescent membrane head.

The concentration of oxygen molecules can be calculated by detecting the phase difference between fluorescence and excitation light and comparing it with the internal calibration curve, and outputs the final value after temperature and salinity compensation.