# RS485 Fluorescence Dissolved Oxygen Sensor (Seawater)

**Type:** Product page · **SKU:** SEN0681 · **Brand:** [DFRobot](https://core-electronics.com.au/brands/dfrobot-australia)
**Page:** https://core-electronics.com.au/dfrobot-rs485-fluorescence-dissolved-oxygen-sensor-seawater-modbus-rtu-ip68.html ([markdown](https://core-electronics.com.au/dfrobot-rs485-fluorescence-dissolved-oxygen-sensor-seawater-modbus-rtu-ip68.html.md))

Measure DO in seawater with this RS485 fluorescence sensor. IP68, maintenance-free, and ModBus-ready. Ideal for mariculture and ocean monitoring...

## Pricing

- **Price:** $336.00 (inc GST) — $305.45 AUD, exc GST

## Availability & dispatch

- Available with a lead time — expect dispatch between Sep 01 and Sep 07.

## Description

This RS485 Fluorescence Dissolved Oxygen Sensor is an advanced monitoring instrument specifically engineered for high-salinity applications. It operates on the principle of fluorescence quenching to provide stable, accurate readings across a 0-20 mg/L (0-200% saturation) range. Unlike traditional electrochemical sensors, this method eliminates the need for electrolytes and avoids electrode polarization, ensuring long-term reliability with minimal maintenance. Featuring an industrial-standard RS485 ModBus-RTU interface, a wide 10-30V DC power supply, and automatic temperature compensation, this sensor is designed for easy integration and dependable performance in demanding marine environments.

![Probe of RS485 Fluorescence Dissolved Oxygen Sensor](https://dfimg.dfrobot.com/enshop/image/data/SEN0681/1_0x0.jpg.webp)

**Optimized for Saline Environments**

This seawater version is specifically designed for high-salinity waters. It utilizes specialized calibration and advanced algorithms to accurately compensate for the effects of salinity on dissolved oxygen measurement, ensuring reliable data integrity in oceans and marine aquaculture farms.

**Stable Fluorescence Measurement**

The sensor measures the phase difference between an excited red light and a reference light, a value inversely proportional to the oxygen concentration. This fluorescence-based method does not consume oxygen during measurement and requires no electrolyte replacement, drastically reducing operating costs and service frequency.

![Stable Fluorescence Measurement of S485 Fluorescence Dissolved Oxygen Sensor](https://dfimg.dfrobot.com/enshop/image/data/SEN0681/2_0x0.jpg.webp)

**Robust IP68 Stainless Steel Construction**

Built to withstand harsh marine conditions, the probe is constructed from 316 stainless steel. It features an overall IP68 waterproof rating, providing excellent resistance to corrosion, salt, and alkali. This durable design ensures continuous operation in submerged, high-pressure (up to 0.6MPa) environments.

**RS485 ModBus-RTU Interface**

Equipped with an RS485 communication interface supporting the standard ModBus-RTU protocol, the sensor is easily integrated into PLCs, data loggers, and other industrial monitoring systems. A built-in temperature sensor provides real-time data and enables automatic temperature compensation, further guaranteeing measurement accuracy.

### Specification

13. Power Supply: DC10-30V
14. Power Consumption: 0.2W
15. Communication Interface: RS485 (Standard ModBus-RTU Protocol)
16. Measurement Principle: Fluorescence
17. Measuring Range: 0-20mg/L, 0-200% Saturation
18. Measurement Error: ±3% FS; ±0.5°C (25°C)
19. Resolution: 0.01mg/L; 0.1%; 0.1°C
20. Response Time: =60s
21. Operating Temperature: 0-40°C
22. Fluorescent Film Lifespan: 1 year under normal use
23. Waterproof Rating: IP68
24. Pressure Resistance: 0.6MPa
25. Cable Length: 5m
26. Casing Material: Corrosion-Resistant Plastic
### Documents

28. [Product wiki](https://wiki.dfrobot.com/SKU_SEN0681_RS485_Dissolved_Oxygen_Sensor_Seawater)

## Images

- [Product image 1](https://core-electronics.com.au/media/catalog/product/S/E/SEN0681-1.jpg)