HOBO ONSET CTD Sensor

Onset CTD Sensor for MX800 Series

A Conductivity/Temperature/Depth sensor for use with HOBO MX800 Series Water Loggers with sensor options available for 4 mt, 9 mt, 30.6 mt or 76.5 mt (13, 30, 100 or 250 ft) in a wide range of underwater environments; for use in freshwater or saltwater.

The CTD sensor is an interchangeable sensor that works with HOBO MX800 Series Water Loggers to measure conductivity, temperature, and water level. With this sensor attached to a HOBO MX800 Series Water Logger, the logger can also calculate specific conductance, salinity, and total dissolved solids (TDS). The CTD sensor can be attached directly to the fully submersible MX801 model, or attached via cable to the direct read MX802 model, which doesn’t require having to pull the sensor out of the water to download data.

Key Features

• 4-electrode conductivity sensor provides wide measurement range for monitoring freshwater or saltwater
• Conductivity sensor is centrally located to minimize effects from stilling wells or protective guards
• Durable ceramic water level sensor, located in the sensor tip for accurate measurement of shallow water levels
• Get water level directly with the MX802, no need for post-processing
• 2.5 cm (1 in) diameter for use in narrow wells (with cable to MX802 above the well)
• Temperature sensor placement near the sensor tip for fast response time
• Specially treated stainless steel holds up in saltwater

• Specifications
• In the Box
• Required Items
• Optional Items

• Variable	Measurement Type	Related SKU	Measurement Units	Notes
  Electrical Conductivity	Direct Measurement	All (W-CTD-01 to 04)	µS/cm	Measures the water's ability to conduct an electrical current.
  Specific Conductance	Calculated	All (W-CTD-01 to 04)	µS/cm	Conductivity automatically compensated for temperature.
  Salinity	Calculated	All (W-CTD-01 to 04)	PSU	Calculated based on the PSS-78 standard.
  Total Dissolved Solids (TDS)	Calculated	All (W-CTD-01 to 04)	mg/L	Concentration of dissolved mineral substances in the water.
  Temperature	Direct Measurement	All (W-CTD-01 to 04)	°C	Range from -20° to 50°C. Essential for automatic compensations.
  Absolute / Raw Pressure	Direct Measurement	All (W-CTD-01 to 04)	kPa / psia	Total pressure detected by the ceramic sensor element.
  Water Level / Depth (Short Range)	Calculated / Direct	W-CTD-04	0 to 4 mt (0 to 13 ft)	Ideal for very shallow waters. Maximum error of 0.6 cm (0.02 ft).
  Water Level / Depth (Standard Range)	Calculated / Direct	W-CTD-01	0 to 9 mt (0 to 30 ft)	Standard setup for wells or streams. Maximum error of 1.0 cm (0.03 ft).
  Water Level / Depth (Medium Range)	Calculated / Direct	W-CTD-02	0 to 30.6 mt (0 to 100 ft)	For intermediate depth applications. Maximum error of 3.0 cm (0.1 ft).
  Water Level / Depth (High Range)	Calculated / Direct	W-CTD-03	0 to 76.5 mt (0 to 251 ft)	Designed for deep wells. Maximum error of 7.6 cm (0.25 ft).
  Sensor Diameter	Physical Dimension	All (W-CTD-01 to 04)	2.5 cm (0.08 ft)	Sized specifically for deployment in narrow wells (1 inch).
  Sensor Length	Physical Dimension	All (W-CTD-01 to 04)	18.7 cm (0.61 ft)	Total length of the cylindrical sensor body (7.37 inches).

   

  Conductivity Measurements
  Measurement Range	Electrical conductivity and specific conductance: 0 to 100,000 µS/cm Salinity using PSS-78: 2 to 42 PSU Total Dissolved Solids (TDS): 0 to 100,000 mg/L
  Calibrated Range	Electrical conductivity: 50 to 80,000 µS/cm 5° to 35°C (41° to 95°F)
  Accuracy	Conductivity: ±2% or 15 µS/cm Salinity: ±2% of reading or 0.1 PSU
  Temperature Measurements
  Range	-20° to 50°C (-40° to 122°F)
  Accuracy	±0.15°C (±0.27°F)
  Resolution	0.01°C at 25°C
  Sensor Physical Specifications
  Dimensions	2.5 cm diameter, 18.7 cm length
  Weight	177 g (0.39 lb / 6.24 oz)
  Environmental Rating	IP68

  Water Level Measurements W-CTD-01
  Range	0 to 207 kPa (0 to 30 psia)
  Accuracy	Typical error: ±0.05% FS
  Resolution	<0.02 kPa (0.003 psi)
  Water Level Measurements W-CTD-04
  Range	0 to 145 kPa (0 to 21 psia)
  Accuracy	Typical error: ±0.075% FS
  Resolution	<0.014 kPa (0.002 psi)

• • 1x CTD Sensor
• • Data Logger MX800 Series
• • Antifouling Protective Guard
  • Accessories
  • Communication Cables