The HOBO U20L-04 is a low-cost, research-grade water level data logger for continuously measuring water level and temperature in a wide range of underwater environments. It features 0.1% measurement accuracy, a polypropylene housing for use in both fresh and salt water, and a non-vented design for convenient and hassle-free deployment.
This data logger requires either the U-DTW-1 Waterproof Shuttle or the Base-U-4 Base Station for configuration and data offload, HOBOware software (free download). NOTE: HOBOware Pro is required when using the U-DTW-1 Waterproof Shuttle. See compatible items below.
• Self-contained non-vented design enables easy deployment
• Ideal for use in both fresh and saltwater environments, including wells, streams, lakes, wetlands, and tidal areas
• Depths up to 13 feet
• Durable ceramic pressure sensor withstands freezing
• HOBOware Pro software provides easy conversion to accurate water level reading, fully compensated for barometric pressure (see demo), temperature, and water density.
Pressure (Absolute) and Water Level Measurements U20L-04
|Operation Range||0 to 145 kPa (0 to 21 psia); approximately 0 to 4 m (0 to 13 ft) of water depth at sea level, or 0 to 7 m (0 to 23 ft) of water at 3,000 m (10,000 ft) of altitude|
|Factory Calibrated Range||69 to 145 kPa (10 to 21 psia), 0° to 40°C (32° to 104°F)|
|Burst Pressure||310 kPa (45 psia) or 18 m (60 ft) depth|
|Water Level Accuracy*||Typical error: ±0.1% FS, 0.4 cm (0.013 ft) water|
|Maximum error: ±0.2% FS, 0.8 cm (0.026 ft) water|
|Raw Pressure Accuracy**||±0.3% FS, 0.43 kPa (0.063 psi) maximum error|
|Resolution||<0.014 kPa (0.002 psi), 0.14 cm (0.005 ft) water|
|Pressure Response Time (90%)***||<1 second at a stable temperature; measurement accuracy also depends on temperature response time|
|Operation Range||-20° to 50°C (-4° to 122°F)|
|Accuracy||±0.44°C from 0° to 50°C (±0.79°F from 32° to 122°F), see Plot A in manual|
|Resolution||0.10°C at 25°C (0.18°F at 77°F), see Plot A in manual|
|Response Time (90%)||10 minutes in water (typical)|
|Stability (Drift)||0.1°C (0.18°F) per year|
|Real-time Clock||±1 minute per month 0° to 50°C (32° to 122°F)|
|Battery||2/3 AA, 3.6 Volt lithium, factory-replaceable|
|Battery Life (Typical Use)||5 years with 1 minute or greater logging interval|
|Memory (Non-volatile)||64K bytes memory (approx. 21,700 pressure and temperature samples)|
|Weight||Approximately 154 g (5.43 oz) in air Approximately 53.9 g (1.9 oz) in fresh water|
|Dimensions||3.18 cm (1.25 inches) diameter, 15.24 cm (6.0 inches) length; mounting hole 6.3 mm (0.25 inches) diameter|
|Wetted Materials||Polypropylene housing and lanyard; Viton and Buna-N O-rings; ceramic sensor in acetyl end cap; stainless steel screws suitable for saltwater|
|Logging Interval||Fixed-rate or multiple logging intervals, with up to 8 user-defined logging intervals and durations; logging intervals from 1 second to 18 hours. Refer to the HOBOware User’s Guide for details.|
|Launch Modes||Immediate start and delayed start|
|Offload Modes||Offload while logging; stop and offload|
|Battery Indication||Battery voltage can be viewed in status screen and optionally logged in datafile. Low battery indication in datafile.|
The CE Marking identifies this product as complying with all relevant directives in the European Union (EU).
* Water Level Accuracy: With accurate reference water level measurement, known water density, accurate Barometric Compensation Assistant data, and a stable temperature environment.
** 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. Maximum error due to rapid thermal changes is approximately 0.5%
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