ST-772 Series Dissolved Oxygen Sensors

        The ST-772 Series Dissolved Oxygen (DO) Sensors perform online measurement of dissolved oxygen content in water based on the fluorescence quenching principle. Integrating Pyxis’ advanced technology in fluorescence detection, the ST-772 adopts a dual-light-source detection technology (excitation light source and reference light source), featuring a wide detection range and low detection limit—capable of detecting dissolved oxygen at concentrations in both μg/L and mg/L ranges. The sensor is integrated with a temperature and pressure sensor, which enables temperature and pressure compensation for dissolved oxygen measurements.

        The replaceable fluorescent cap at the sensor tip is fully independently developed by Pyxis, with a typical service life of up to two years. It is covered with black microporous PTFE (polytetrafluoroethylene) material, offering excellent scratch resistance. The sensor tip is designed with a flat structure, which is not easily contaminated and easy to clean. The entire sensor is made of 304 stainless steel, ensuring greater durability.

Typical Applications

        Dissolved oxygen concentration monitoring in fields such as sewage treatment plants, water treatment plants (tap water), water stations, surface water, and industrial water systems.

Instrument Features

• The fluorescent membrane has a typical service life of up to two years and is scratch-resistant; no requirement for flow rate or agitation; no need to replace solid electrodes/electrolytes.

• Built-in temperature and pressure sensors for automatic compensation, ensuring accurate and stable measurements with ultra-low drift.

• Built-in transmitter: no display unit required, directly outputting isolated RS485 and 4-20mA signals for more stable and accurate long-distance transmission.

• Calibration, data logging, and diagnostics can be performed on a PC or smartphone via a Bluetooth adapter. Slope calibration of the sensor can be done using air or oxygen-saturated water, while zero-point calibration can be performed using saturated oxygen-free water or nitrogen.

• Optional submersible mounting accessories are available, suitable for dissolved oxygen monitoring in filter tanks for sewage, tap water, and other applications.