U24 Conductivity & Salinity Loggers

Low cost conductivity/salinity and temperature datalogger

The HOBO U24-001 Conductivity Logger is a high-accuracy, cost-effective data logger for measuring conductivity and temperature in streams and lakes. Ideal for monitoring aquifers for saltwater intrusion and road and agricultural runoff, the U24 is easy to deploy and maintain. It features a non-contact sensor to minimize drift-related measurement errors, open access to the sensor for cleaning, and software-based drift compensation. HOBOware Pro software enables start/end-point calibration to compensate for any fouling and provides easy conversion to specific conductance and salinity.

The U24-002-C model is for saltwater environments with relatively small changes in salinity (±5,000 μS/cm) such as saltwater bays, or to detect salinity events such as upwelling, rainstorm, and discharge events. This logger can also be used to gather salinity data for salinity compensation of HOBO U26 Dissolved Oxygen logger data. Note: This logger is not intended for monitoring salinity levels in waters with widely changing salinities as it can have significant measurement error and drift in those environments. See specifications below.


  U24-001 Conductivity
U24-002-C Salinity


Calibrated Range

Low: 0 to 1000 μS/cm
High: 0 to 10,000 μS/cm

Low: 100 to 10,000 μS/cm
High: 5000 to 55,000 μS/cm
5 to 35°C

Low: 3% of reading, or 5 μS/cm, whichever is greater
High: 3% of reading, or 20 μS/cm, whichever is greater

Low: 3% of reading, or 50 μS/cm, whichever is greater
High: 5% of reading, in waters within a range of ±3,000 μS/cm;
waters with greater variation can have substantially greater error
Resolution 1 μS/cm 2 μS/cm
Drift < 3% per year Up to 12% per month. Use monthly start and end point calibration to compensate  


  • Memory - 14,400 sets of measurements when using both conductivity ranges (64kb)
  • Battery life - 3 years (@ 1 min logging)
  • Maximum Depth - 70m
  • Operating Range - 0 to 50°C - non freezing
  • Dimensions: 3.18cm diam. x 16.5cm, with 6.3 mm mounting hole
  • Response time - 1 second to 90% of change


About the manufacturer

Based on Cape Cod, Massachusetts, Onset has been designing and manufacturing its data loggers and monitoring solutions on site since the company's founding in 1981. Specialising in miniature, battery powered solutions, Onset data loggers are exceptional quality and value, ranging from indoor to outdoor and underwater applications. HOBO® data logger and weather station products are used around the world in a broad range of monitoring applications, from verifying the performance of green buildings and renewable energy systems to agricultural and coastal research.

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U24 conductivity logger brochure

File Size 245KB   Filename onset_hobo_u24_data_loggers-1.pdf   Download
Optional protective enclosure available as pictured

Optional protective enclosure available as pictured

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