U24-002 Salt Water Conductivity Data Logger

Description

The HOBO U24-002 Conductivity/Salinity Logger is a high-accuracy, cost-effective data logger for measuring salinity, conductivity and temperature in 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. The logger significantly reduces the cost of conductivity/salinity monitoring while making logger maintenance easier than ever.

IMPORTANT: The Hobo Pro software and base unit need to be purchased with this logger. Please order via the Recommended products area (below).

When monitoring salinity in waters with more than +/-5,000 uS/cm variation, refer to the accuracy shown in Plot C in the product specifications to determine if the accuracy is acceptable for your needs. Monthly field calibration readings are typically required to achieve the best accuracy.

Features

• Non-contact sensor reduces measurement error from fouling
• Provides easy access to sensor for cleaning and shedding air bubbles
• Two user-selectable ranges provide measurements from 100 to 55,000 uS/cm.
• The 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

Specifications

• Measurements: Actual Conductivity, Temperature, Specific Conductance at 25C (calculated), Salinity (calculated using PSS-78, the Practical Salinity Scale 1978)
• Conductivity Measurement Range: (Calibrated Range)
  High Range: 5000 to 55,000 uS/cm 
  Low Range: 100 to 10,000 uS/cm
  Over the range of 5 to 35C (41 to 95F)
• Conductivity Extended Ranges
  Low Range: 50 to 30,000 μS/cm
  High Range: 1,000 to 55,000 μS/cm
  (readings below these ranges reported as 0)
• Temperature Measurement Range: -2 to 36C (28 to 97F)

Plot A: Salinity Range (U24-002)*

Plot B: Specific Conductance Range in Saltwater

Plot C: Specific Conductance High-Range Accuracy

• Accuracy: 
  
  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 of the calibration point; waters with greater
  variation can have substantially greater error (see Plot C)
  Temperature: 0.1°C (0.2°F) (in calibrated range)
• Resolution:
  Conductivity: 2 uS/cm 
  Temperature: 0.01°C (0.02°F)
• Drift:
  Conductivity: Up to 12% sensor drift per month, exclusive of drift from fouling.
  Monthly start- and end-point calibration should be used with
  HOBOware Conductivity Assistant to achieve the specified Specific
  Conductance accuracy
• 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; 14,400 sets of measurements when using both conductivity ranges (64kbytes)
• 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.

Applications

 Include:

• Climate studies
• Irrigation management
• Ocean ecology
• Storm water impact
• Wetlands restoration
• Environmental impact
• Water Quality monitoring