YSI - a Xylem brand  


An easy way to install YSI ODO™ technology at your site, tank, or pond.

Engineered specifically for aquaculture applications, but at home in any Modbus system, the optical dissolved oxygen (ODO) sensor can be used to ensure adequate oxygen levels for your livestock or for improved energy efficiency. With YSI’s ODO RTU (Remote Terminal Unit), you’ll benefit from reduced costs, less maintenance, and better data.

ODO RTU utilizes the most advanced DO technology and can be connected anywhere without the need for special connectors. Additional inputs for barometric pressure and salinity are used to accurately calculate the DO% and mg/L. ODO RTU is also available with built-in conductivity measurement to automatically compensate for salinity. 

  • Specifications
  • Manuals and FAQ
  • Specification Sheets
  • Technical Notes
  • Documents

Key Benefits

Smarter Sensors
Industry-leading optical dissolved oxygen provides higher accuracy readings with less maintenance

Seamless Integration
Modbus communication integrates directly to the PLC or data logger you already have without additional software

Automatic Compensation
An optional built-in conductivity sensor automatically compensates for salinity - removing the guesswork

Less Maintenance, Long Warranty
2-year cable and probe warranty with user-replaceable DO cap

Not for use with the ProSolo or ProODO handheld meters.


Modbus/RS485 (4 wire)

Default Baud Rate

9600 (user programmable)

Dissolved Oxygen (Optical luminescence) Units

Range  0 to 500%, 0 to 50 mg/L

Accuracy  0 to 200%: ±1% of reading or

1% saturation, whichever is greater;

200 to 500%: ±8% of reading;

0 to 20 mg/L: ±0.1 mg/L

or 1% of reading, whichever is greater;

20 to 50 mg/L: ±8% of reading

Resolution   0.01 mg/L and 0.1 %, or

0.1 mg/L and 1% (auto-adjusted based on range)


10 V to 16 V DC, 15 mA max

2.46 cm diameter,

Cable options for 1, 4, 10, 20, 30, 50, and 100 m lengths

Temperature (Thermistor) Units

Range  –5 to 70°C (-5 to 50°C; DO compensation range for mg/L )

Accuracy  ±0.2°C

Resolution   0.1°C or 0.1°F (auto-adjusted based on range)


2 years on cable, probe, and ODO sensor cap

Additional Conductivity Specifications

Conductivity (Four nickel electrode cell) Units: μS/cm, mS/cm

Range  0 to 200 mS/cm

Accuracy  0 to 100 mS/cm ±0.5% of reading or 0.001 mS/cm, whichever is greater; 100 to 200 mS/cm ±1.0% of reading

Resolution   0.001, 0.01, or 0.1 μS (range dependent)

Salinity Units:

μS/cm, mS/cm
Range  0 to 70 ppt

Accuracy  ±1.0% of reading or ±0.1 ppt, whichever is greater

Resolution   0.01 ppt