HOBO Salt Water Conductivity/Salinity Data Logger

A 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. Data from this logger can be used with data from the HOBO U26 Dissolved Oxygen Logger for monitoring percent dissolved oxygen saturation.

Note: 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 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

In what environment does this data logger operate?

This data logger operates in outdoor and underwater environments.

What measurements does this data logger support?

The U24-002-C data logger supports the following measurements: Conductivity/Salinity and Temperature

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)
Temperature Measurement Range:	5 to 35C (41 to 95F)
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 (see Plot C)
Conductivity:	2 uS/cm
Temperature:	0.01°C (typical 0.02°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.
Response time:	1 second to 90% of change (in water)
Operating range:	64K bytes – 16K to 23K tips when recording rain only; 25K to 30K data points when recording rain and temperature-2 to 36C (28 to 97F) – non-freezingtd>
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:	Less than 0.1°C/year (0.2°F/year)
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 the relevant directives in the European Union (EU).