Water Quality Dissolved Oxygen Sensor, 0~20mg/L, RS485

Equipped with a fluorescence measurement principle, this water quality dissolved oxygen sensor is available for sale. The dissolved oxygen sensor features a measurement range of 0 to 20 mg/L, supports RS485 (Modbus RTU) output, and incorporates automatic temperature compensation (Pt1000) to ensure reliable readings across varying environments. The T90 response time is less than 30 seconds, enabling rapid capture of oxygen concentration changes in water bodies.

Feature

• The water quality dissolved oxygen sensor employs a fluorescence measurement method, eliminating the need for electrolytes and preventing polarization. It remains unaffected by flow velocity and offers superior long-term stability.
• The sensor incorporates high-precision temperature and salinity compensation modules that automatically adjust for environmental changes, ensuring more accurate and reliable readings.
• SUCH water quality sensors demonstrate excellent resistance to chemical interference, unaffected by substances like sulfides. They exhibit minimal drift, fast response times, and suitability for diverse complex water bodies.
• The fluorescent membrane head is easily replaceable with low maintenance requirements. It supports both RS485 interfaces and Modbus-RTU protocol, featuring low power consumption and robust anti-interference design for extended service life.

Dimension (unit: mm)

Detail

Calibration

Zero Calibration: Weigh 5g sodium sulfite using a balance. Measure 95mL water with a 250mL graduated cylinder. Pour water into a beaker, add weighed sodium sulfite, and stir thoroughly with a glass rod until dissolved to obtain a 5% sodium sulfite solution. Immerse the sensor in the solution. After 3 minutes when readings stabilize, perform zero calibration.

Slope Calibration: Place the sensor in air-saturated water. After approximately 3 minutes when the reading stabilizes, perform slope calibration.

Preparation of Air-Saturated Water: Add 2/3 of the volume of fresh distilled water to a constant-temperature water bath. Float a porous plastic plate on the water surface (see left side of the image above). Simultaneously, continuously aerate the water using a bubbler (air pump) for over 1 hour. After stopping aeration, allow the water to settle for approximately 20 minutes to obtain air-saturated water. Immerse the sensor in the water and perform slope calibration once the readings stabilize.

Note: As an alternative, slope calibration may also be performed in air saturated with water vapor. Fill the calibration cup with pure water to a level approximately 1 mm below the column height. Gently shake the sensor's fluorescent membrane head after wetting it (ensuring the membrane surface is moist without droplets). Place the water quality sensor vertically on the calibration cup column (as shown on the right in the figure above, ensuring the water surface does not touch the fluorescent membrane). Wait 3 minutes for the reading to stabilize before calibrating the slope.

Wiring Diagram