Luminescence dissolved oxygen sensor DFDO-700

digitalRS-485Modbus

Product Overview
The dissolved oxygen (DO) sensor adopts advanced fluorescence quenching technology. When blue light emitted by the sensor irradiates the fluorescent substance on the fluorescent cap, the substance is excited to emit red light. Since oxygen molecules can carry away energy (quenching effect), the duration and intensity of the excited red light are inversely proportional to the oxygen molecule concentration—enabling accurate calculation of dissolved oxygen levels in water. Widely applicable for online DO monitoring, it is ideal for sewage treatment plants (regulating tanks, biochemical tanks, effluent), waterworks, surface water, industrial process water, aquaculture, and other related industries.

Measurement Principle
This DO analyzer employs fluorescence technology for dissolved oxygen detection. The sensor cap is coated with a luminescent material: when LED-emitted blue light irradiates the material, it is instantly excited to release red light. The duration and intensity of the red light are inversely proportional to the oxygen molecule concentration, allowing precise calculation of DO levels.

Key Features

• Equipped with a new oxygen-sensitive membrane and NTC temperature compensation, ensuring excellent measurement repeatability and stability.
• No oxygen consumption during measurement; no requirement for water flow rate or stirring.
• Innovative fluorescence technology: membrane-free, electrolyte-free, and nearly maintenance-free.
• Built-in self-diagnostic function to guarantee data accuracy.
• Factory-calibrated, with 1-year calibration-free operation; on-site calibration supported.
• Digital sensor design for strong anti-interference capability and long transmission distance.
• Standard digital signal output enables integration and networking with other devices without an additional controller.
• Plug-and-play functionality for quick, easy installation.

Applications

• Online DO monitoring for sewage treatment plants (regulating reservoirs, biochemical pools, effluent, etc.).
• Online DO monitoring for waterworks, surface water, industrial process water, aquaculture, and related fields.

Technical Specifications
Parameter | Details
Measurement Range | DO: 0~20mg/L or 0~200% saturability
| Temperature: 0~45℃ (with automatic temperature compensation)
Measurement Accuracy | DO: ±3% of measured value or ±0.3mg/L (whichever is greater)
| Temperature: ±0.5℃
Repeatability | ±0.3mg/L
Resolution | 0.01mg/L
Pressure Range | ≤0.3Mpa
Materials | Body: SUS316L (Ordinary Version) / Titanium Alloy (Seawater Version)
| Upper & Lower Covers: PPS + Glass Fiber
| Cable: PUR
Power Supply | 9~28VDC
Communication Protocol | MODBUS RS485
Storage Temperature | -15~60℃
Operating Temperature | 0~45℃ (no freezing)
Weight | 1.4KG
Protection Level | IP68/NEMA6P
Cable Length | Standard: 10m; Maximum extendable to 100m

Characteristics / Technical Specifications

• Model: DFDO-700
• Measurement Range: DO: 0~20mg/L or 0~200% saturability; Temperature: 0~45℃
• Measurement Accuracy: DO: ±3% of measured value or ±0.3mg/L; Temperature: ±0.5℃
• Repeatability: ±0.3mg/L
• Resolution: 0.01mg/L
• Pressure Range: ≤0.3Mpa
• Materials: SUS316L/Titanium Alloy, PPS + Glass Fiber, PUR cable
• Power Supply: 9~28VDC
• Communication Protocol: MODBUS RS485
• Storage Temperature: -15~60℃
• Operating Temperature: 0~45℃ (no freezing)
• Weight: 1.4KG
• Protection Level: IP68/NEMA6P
• Cable Length: Standard 10m, extendable to 100m