Onset HOBO U24-002-C Salt Water Conductivity/Salinity Data Logger

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Onset HOBO U24-002-C Salt Water Conductivity/Salinity Data Logger

  • Vendor:Onset

Availability: Available Item


A miniature, waterproof, value-priced, two-channel temperature and relative light level data logger. Suitable for indoor, outdoor, and underwater applications, this logger holds approximately 6.5K of 10-bit readings. For accurate temperature measurement in sunlight, a solar radiation shield is required (assembly-required RS1 Solar Radiation Shield or pre-assembled M-RSA Solar Radiation Shield). Note that using a solar radiation shield prevents the use of the light sensor.


  • Non-contact sensor provides long life
  • Easy access to sensor for cleaning and shedding air bubbles
  • Two user-selectable ranges provide measurements from 100 to 55,000 uS/cm
  • Delrin housing will not corrode in saltwater
  • HOBOware Pro software enables start/end-point calibration to compensate for any fouling and provides easy conversion to specific conductance and salinity using the Practical Salinity Scale 1978 (PSS-78)
  • USB optical interface provides high-speed, reliable salinity data offload in wet environments
  • Compatible with the HOBO Waterproof Shuttle for easy and reliable data retrieval and transport
  • Non-contact sensor with titanium pentoxide coating keeps the sensor from coming in contact with the water, thereby preventing tarnishing or corrosion associated with traditional electrode sensors; sensor coating is inert, so fouling can be wiped off easily

Measurement : Actual Conductivity, Temperature, Specific Conductance at 25C (calculated), Salinity (calculated using PSS-78, the Practical Salinity Scale 1978)


Measurement Range

Temperature: 5 to 35C (41 to 95F)

Conductivity Measurement Range (Calibrated Range)

High range: 5000 to 55,000 uS/cm
Low range: 100 to 10,000 uS/cm

Specific Conductance Accuracy

(in Calibrated Range using Conductivity Assistant and Calibration Measurements)

Low range: 3% of reading or 50 µS/cm, whichever is greater
High range: 5% of reading, in waters within a range of ±3,000 µS/cm; waters with greater variation can have substantially greater error
Temperature Accuracy: 0.1°C (0.2°F) at 25°C (77°F)
Conductivity drift: Up to 12% sensor drift per month, exclusive of drift from fouling. Monthly start- and end-point calibration should be used with the HOBOware Conductivity Assistant to achieve the specified Specific Conductance accuracy.


Conductivity Resolution: 2 uS/cm
Temperature Resolution: 0.01°C (0.02°F)


Response time: 1 second to 90% of change (in water)
Operating range: -2 to 36C (28 to 97F) – non-freezing
Memory:  18,500 temperature and conductivity measurements when using one conductivity range; 11,500 sets of measurements when using both conductivity ranges (64 KB total memory)
Sample rate: 1 second to 18 hrs, fixed or multiple-rate sampling with up to 8 user-defined sampling intervals
Clock accuracy: +/- 1 minute per month
Battery life: 3 years (@ 1 min logging)
Maximum depth: 70 m (225')
Weight: 193 gm (6.82 ounces), buoyancy in freshwater: -59.8 gm (-2.11 ounces)
Size: 3.18 cm diameter x 16.5 cm, with 6.3 mm mounting hole (1.25" diameter x 6.5", ¼" hole)
Wetted housing materials: Delrin housing, epoxy, stainless steel retaining ring, polypropylene, Buna rubber O-ring, titanium pentoxide (inert coating over sensor) – all materials are suitable for long-term use in saltwater.
CE compliance: The CE Marking identifies this product as complying with all relevant directives in the European Union (EU).