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.
(1) Barometric Pressure Compensation Assistant Demo｜view
(2) Multi-rate Sampling Demo｜view
- 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
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 U20L-04 data logger supports the following measurements: Absolute Pressure, Barometric Pressure, Temperature and Water Level
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="" 14="" cm="" 005="" ft="" water="" li="">
- Pressure Response Time (90%)***：<1 second="" at="" a="" stable="" temperature="" measurement="" accuracy="" also="" depends="" on="" response="" time="" li="">
- 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.
- Environmental Rating：IP68
：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%