Desun Uniwill DS380 Fluorescence Dissolved Oxygen Sensor, 0–20 mg/L, RS485 Modbus Output, IP68 Submersible

The DS380 operates from a 6 to 12V DC power source and draws less than 50mA. Ensure your power supply is stable and properly rated for outdoor or wet location use if deployed in the field. The RS485 communication lines should be connected to a compatible MODBUS master device.

Unlike Clark-type sensors that consume oxygen and require electrolyte and membrane replacement, the DS380 uses an optical fluorescence method. An oxygen-sensitive fluorescent layer is excited by an LED; the decay time of the fluorescence is inversely proportional to oxygen concentration. This makes it maintenance-free, flow-independent, and not prone to fouling from sulfides or other chemicals.

The sensor uses standard MODBUS RTU protocol. The default slave address is typically configurable (e.g., 01). Key data, such as dissolved oxygen concentration (mg/L or % saturation) and temperature, are held in specific holding or input registers. Consult the manufacturer's datasheet for the exact register map, baud rate (commonly 9600 or 19200), and parity settings required for your PLC or SCADA system integration.

Yes, the DS380 is well-suited for saline environments. Its housing is constructed from SS316 stainless steel or titanium alloy, both offering excellent corrosion resistance against saltwater. The IP68 rating ensures it can be continuously submerged. The optical sensing principle is not affected by salinity, unlike some electrochemical sensors.

The sensor requires initial calibration, typically a one-point or two-point calibration in air-saturated water and/or zero-oxygen solution (using sodium sulfite). Calibration is performed via MODBUS commands sent to the sensor's internal controller. Once calibrated, the maintenance-free design means it can operate for extended periods without recalibration under stable conditions.