> **Source:** Core Electronics is an Australian maker-electronics retailer and manufacturer based in Newcastle, NSW, run by a team of makers and educators. We design and manufacture our own product lines (PiicoDev, CE originals) and are official retailers for iconic maker and industrial brands including Raspberry Pi, Arduino, Adafruit, SparkFun and DFRobot. Orders ship Australia-wide from our Newcastle warehouse. Prices are in AUD and include GST. Pricing, stock and dispatch on this page are generated from the store's live catalog. Full machine-readable index: https://core-electronics.com.au/llms.txt # RS485 Fluorescence Dissolved Oxygen Sensor (Freshwater) **Type:** Product page · **SKU:** SEN0680 · **Brand:** [DFRobot](https://core-electronics.com.au/brands/dfrobot-australia) **Page:** https://core-electronics.com.au/dfrobot-rs485-fluorescence-optical-dissolved-oxygen-sensor-freshwater-modbus-rtu-ip68.html ([markdown](https://core-electronics.com.au/dfrobot-rs485-fluorescence-optical-dissolved-oxygen-sensor-freshwater-modbus-rtu-ip68.html.md)) Measure dissolved oxygen in freshwater aquaculture or wastewater treatment with this IP68 sensor. Uses fluorescence (no maintenance) and RS485 ModBus.... ## Pricing - **Price:** $320.70 (inc GST) — $291.55 AUD, exc GST ## Availability & dispatch - Available with a lead time — expect dispatch between Aug 18 and Aug 24. ## How to buy - **Build a cart:** compose `https://core-electronics.com.au/cart/link?items=SEN0680:1` (comma-separated SKU:qty pairs) and share the link. Opening it shows a confirmation page with live pricing and stock before anything is added to the cart. - **Verify the cart first:** fetch `https://core-electronics.com.au/cart/link/SEN0680:1.md` for live line prices (inc & exc GST, quantity discounts applied), stock and dispatch estimates, and totals. Append `/to/{AU-postcode}` (or `/to/{country-code}:{postcode}`) before `.md` for delivery options and prices to that destination. Unknown, retired, or out-of-stock SKUs are flagged. (Query form `cart/link.md?items=...` also works but some robots parsers refuse query strings here.) - **Checkout** is completed on-site and includes a captcha at the payment step. Share the cart link; checkout takes it from there. - **Search the catalogue:** `https://core-electronics.com.au/search/{query}.md` (URL-encode the query; pages 2-3 at `search/{query}/{page}.md`; `search.md?q=` also works) - **Payment methods, purchase orders, policies and contact details:** https://core-electronics.com.au/llms.txt ## Description The RS485 Fluorescence Dissolved Oxygen Sensor (Freshwater) provides a high-stability solution for measuring dissolved oxygen, designed specifically for freshwater environments. It operates on the principle of fluorescence quenching, an optical method that measures the phase shift of light caused by oxygen molecules. This optical DO probe delivers a high-accuracy measurement range of 0-20 mg/L (0-200% saturation) with an error of just ±3% FS. Key advantages include its maintenance-free optical design, built-in automatic temperature compensation, and simple system integration via the standard ModBus-RTU protocol. With a robust IP68 waterproof rating, this water quality instrument is engineered for demanding applications in freshwater aquaculture, wastewater treatment, and long-term environmental monitoring. ![Probe of RS485 Fluorescence Dissolved Oxygen Sensor](https://dfimg.dfrobot.com/enshop/image/data/SEN0680/1_0x0.jpg.webp) **Maintenance-Free Fluorescence Principle** Traditional electrochemical sensors require frequent calibration and electrolyte replacement due to electrode polarization and depletion. This fluorescence dissolved oxygen sensor utilizes an advanced optical method that does not consume oxygen or rely on electrolytes. This design results in excellent long-term stability, significantly reduces maintenance frequency, and lowers the total cost of ownership. **Accurate Data with Automatic Temperature Compensation** Dissolved oxygen levels are highly dependent on water temperature. This ModBus DO sensor integrates a dedicated temperature sensor to monitor water conditions in real time. It automatically applies temperature compensation to every measurement, ensuring accurate and reliable dissolved oxygen concentration and saturation readings, even in environments with fluctuating temperatures. **Seamless System Integration via RS485** The industrial-grade sensor is equipped with an RS485 communication interface and supports the standard ModBus-RTU protocol. This feature allows for reliable, long-distance data transmission and simple integration into existing data platforms, PLCs, data loggers, or other industrial control and monitoring systems. The unit comes factory-calibrated and also supports user-defined zero-oxygen and full-scale calibration via registers for optimization. **Robust Design for Harsh Environments** Engineered for long-term field deployment, the dissolved oxygen sensor is built to last. The probe is constructed from 316 stainless steel, offering superior resistance to corrosion. The entire unit is sealed to an IP68 waterproof rating, ensuring it can be continuously submerged and operate reliably in challenging freshwater conditions, including rivers, lakes, and treatment facilities. ![Robust Design for Harsh Environments](https://dfimg.dfrobot.com/enshop/image/data/SEN0680/2_0x0.jpg.webp) ### Specification - Power Supply: DC10-30V - Power Consumption: 0.2W - Communication Interface: RS485 (Standard ModBus-RTU Protocol) - Measurement Principle: Fluorescence - Measuring Range: 0-20mg/L, 0-200% Saturation - Measurement Error: ±3% FS; ±0.5°C (25°C) - Resolution: 0.01mg/L; 0.1%; 0.1°C - Response Time: =60s - Operating Temperature: 0-40°C - Fluorescent Film Lifespan: 1 year under normal use - Waterproof Rating: IP68 - Pressure Resistance: 0.6MPa - Cable Length: 5m - Casing Material: Corrosion-Resistant Plastic ### Documents - [Product wiki](https://wiki.dfrobot.com/SKU_SEN0680_RS485_Dissolved_Oxygen_Sensor_Freshwater) ## Images - [Product image 1](https://core-electronics.com.au/media/catalog/product/S/E/SEN0680-1.jpg)