| 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 |
| Temperature Measurements |
| 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 |
| Logger |
| 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 |
