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.
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
- 1” 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
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
Calibration Range: Electrical conductivity: 50 to 80,000 µS/cm
5° to 35°C
Accuracy: Conductivity: +/-2% or 15 µS/cm whichever is greater
Salinity: +/-2% of reading or 0.1 PSU, whichever is greater
Resolution:
Conductivity:
0.1 µS/cm from 0 to 1,000 µS/cm
1 µS/cm from 1,000 to 10,000 µS/cm
10 µS/cm from 10,000 to 100,000 µS/cm
TDS: 0.1 mg/L
Salinity: 0.01 PSU
Response Time: 1 second to 90% at a stable temperature
Absolute Pressure and Water Level Measurements W-CTD-01
Range: 0 to 207 kPa (0 to 30 psia); approximately 0 to 9 m of water depth at sea level, or 0 to 12 m of water at 3,000 m of altitude
Factory Calibration Range: 69 to 207 kPa, 0° to 40°C
Burst Pressure: 310 kPa (45 psia) or 18 m (60 ft) depth
Water Level Accuracy*: Typical error: ±0.05% FS, 0.5 cm water
Maximum error: ±0.1% FS, 1.0 cm water
Raw Pressure Accuracy**: ±0.3% FS, 0.62 kPa maximum error
Resolution: <0.02 kPa, 0.21 cm water
Pressure Response Time***: <1 second to 90% at a stable temperature
Absolute Pressure and Water Level Measurements W-CTD-02
Range: 0 to 400 kPa; approximately 0 to 30.6 m of water depth at sea level, or 0 to 33.6 m of water at 3,000 m of altitude
Factory Calibration Range: 69 to 400 kPa, 0° to 40°C
Burst Pressure: 500 kPa or 40.8 m depth
Water Level Accuracy*: Typical error: ±0.05% FS, 1.5 cm water
Maximum error: ±0.1% FS, 3.0 cm water
Raw Pressure Accuracy**: ±0.3% FS, 1.20 kPa maximum error
Resolution: ±0.3% FS, 1.20 kPa maximum error
Pressure Response Time***: <1 second to 90% at a stable temperature
Absolute Pressure and Water Level Measurements W-CTD-03
Range: 0 to 850 kPa; approximately 0 to 76.5 m of water depth at sea level, or 0 to 79.5 m of water at 3,000 m of altitude
Factory Calibration Range: 69 to 850 kPa, 0° to 40°C
Burst Pressure: 1,200 kPa or 112 m depth
Water Level Accuracy*: Typical error: ±0.05% FS, 3.8 cm water
Maximum error: ±0.1% FS, 7.6 cm water
Raw Pressure Accuracy**: ±0.3% FS, 2.55 kPa maximum error
Resolution: <0.085 kPa, 0.87 cm water
Pressure Response Time***: <1 second to 90% at a stable temperature
Absolute Pressure and Water Level Measurements W-CTD-04
Range: 0 to 145 kPa; approximately 0 to 4 m of water depth at sea level, or 0 to 7 m of water at 3,000 m of altitude
Factory Calibration Range: 69 to 145 kPa, 0° to 40°C
Burst Pressure: 310 kPa or 18 m depth
Water Level Accuracy*: Typical error: ±0.075% FS, 0.3 cm water
Maximum error: : ±0.15% FS, 0.6 cm water
Raw Pressure Accuracy**: ±0.3% FS, 0.43 kPa maximum error
Resolution: <0.014 kPa, 0.14 cm water
Pressure Response Time***: <1 second to 90% at a stable temperature
Temperature Measurements (All Models)
Range: -20° to 50°C, non-freezing water
Accuracy: ±0.15°C from 0° to 50°C
Resolution: 0.01°C at 25°C
Response Time: 3 minutes to 90% in water (typical)
Drift: <0.1°C (0.18°F) per year
Sensor
Dimensions: 2.5 cm diameter, 15 cm length
Weight: Approximately xx g in air; approximately xx g in saltwater
Wetted Materials: Passivated 316 Stainless steel housing rated for use in saltwater, Viton and Buna-N O-rings, PET sensor connector
Depth sensor: ceramic
Conductivity sensor: PET, platinum plating on electrodes
Note: Sensor should be mounted so that it is not in contact with other metals
Environmental Rating: IP68; Waterproof to pressure sensor burst pressure rating
CE Compliance Mark
UKCA Compliance Mark
* Water Level Accuracy: With accurate reference water level measurement, known water density, and a stable temperature environment. System Water Level Accuracy equals the sum of the Barometric Water Level Accuracy plus the selected CTD sensor Water Level Accuracy.
** Raw Pressure Accuracy: Absolute pressure sensor accuracy includes all sensor drift, temperature, and hysteresis-induced errors.
*** Changes in Temperature: Allow 20 minutes in water to achieve full temperature compensation of the pressure sensor. There can be up to 0.5% of additional error due to rapid temperature changes.
