DFRobot
DFRobot SEN0681 RS485 Dissolved Oxygen Sensor - Seawater
· MPN: SEN0681
This sensor is designed for monitoring dissolved oxygen in seawater and other high-salinity applications. It uses fluorescence quenching rather than a tradit...
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This sensor is designed for monitoring dissolved oxygen in seawater and other high-salinity applications. It uses fluorescence quenching rather than a traditional electrochemical cell, so it does not consume oxygen during measurement and does not require electrolyte replacement.
The probe measures dissolved oxygen across a 0-20 mg/L, 0-200% saturation range and includes automatic temperature compensation via a built-in temperature sensor. It is intended for demanding marine use such as mariculture, aquaculture, coastal water quality checks and long-term environmental monitoring.
Integration is handled through an industrial RS485 interface using the standard ModBus-RTU protocol, making it suitable for PLCs, data loggers and other monitoring systems. The package includes the RS485 fluorescence dissolved oxygen sensor and a sensor cable, and DFRobot provides a product wiki for setup information.
Features:
- Optimised for saline environments: Designed for high-salinity waters with calibration and algorithms that compensate for salinity effects on dissolved oxygen measurement.
- Stable fluorescence measurement: Measures the phase difference between excited red light and reference light, avoiding oxygen consumption during measurement and eliminating electrolyte replacement.
- Robust IP68 construction: Rated for submerged marine environments with resistance to corrosion, salt and alkali, and operation up to 0.6MPa pressure.
- RS485 ModBus-RTU interface: Supports integration with PLCs, data loggers and industrial monitoring systems.
- Automatic temperature compensation: Built-in temperature sensing provides real-time data for compensated dissolved oxygen readings.
Specifications:
- 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
Useful for automated mariculture and aquaculture monitoring, DIY oceanographic data buoys, estuary and coastal water quality analysis, and industrial process control in saline solutions.
Jargon buster
Plain-language definitions for the technical terms used above.
- Modbus
- Modbus is an industrial communication protocol used by many meters, sensors, PLCs and automation devices. When a product lists Modbus support, it is generally easier to integrate with existing industrial equipment that speaks the same protocol.
- ModBus-RTU
- ModBus-RTU is a common industrial protocol for sending readings and control commands over serial links such as RS485. Knowing a device uses ModBus-RTU helps you choose software libraries, data loggers, or controllers that can request and interpret its data.
- RS485
- RS485 is a robust differential serial communication standard often used in factories, farms and buildings where cables may be long or electrically noisy, and it can link many devices on a single pair of wires. When a product lists RS485, it can communicate with industrial sensors, meters and control equipment over longer distances than typical hobby serial wiring.
- Temperature compensation
- Temperature compensation is when a sensor or instrument adjusts its readings to reduce errors caused by changes in temperature. This matters because a sensor's raw output often drifts as conditions warm or cool, so compensation keeps readings more consistent and accurate over time.
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