Overview
A weatherproof data logger with an external soil/water temperature sensor on a 6-foot cable, for applications where just one temperature probe is required. Also includes an internal temperature sensor.
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Features
- Weatherproof housing for use in outdoor or condensing environments
- High accuracy
- Small-diameter external sensor versions for measurements in tight spaces
- Optic USB interface for fast and reliable download
- Compatible with HOBOware and HOBOware Pro software for logger setup, graphing, and analysis
Specifications
Temperature Sensor
Operation Range
U23-001A internal sensor: -40 to 70°C (-40 to 158°F)
U23-002A external temperature sensor: -40 to 70°C (-40 to 158°F)
U23-003 and U23-004 external sensors: -40 to 100°C (-40 to 212°F), with tip and cable immersion in fresh water up to 50°C (122°F) for one year
Accuracy
U23-001A and U23-002A: ±0.25°C from -40 to 0°C (±0.45 from -40 to 32°F), ±0.2°C from 0 to 70°C (±0.36 from 32 to 158°F)
U23-003 and U23-004: ±0.21°C from 0° to 50°C (±0.38°F from 32° to 122°F); see Plot A
Resolution
U23-001A and U23-002A: 0.04°C (0.072°F)
U23-003 and U23-004: 0.02°C at 25°C (0.04°F at 77°F); see Plot A
Response Time (Typical to 90%)
U23-001A internal sensor: 10 minutes in air moving 1 m/sec
U23-002A external temperature sensor: 3 minutes, 45 seconds in air moving 1 m/sec
U23-003 and U23-004 external sensors: 3 minutes in air moving
1 m/sec; 30 seconds in stirred water
Drift
U23-001A and U23-002A: <0.01°C (0.018°F) per year
U23-003 and U23-004: <0.1°C (0.18°F) per year
Relative Humidity Sensor (U23-001A, U23-002A only)
Operation Range
0 to 100% RH, -40° to 70°C (-40° to 158°F)
Exposure to conditions below -20°C (-4°F) or above 95% RH may temporarily increase the maximum RH sensor error by an additional 1%
Accuracy
±2.5% from 10% to 90% RH typical to a maximum of ±3.5% including hysteresis at 25°C (77°F); below 10% and above 90% ±5% typical
Resolution
0.05%
Response Time (Typical to 90%)
U23-001A: 40 minutes in air moving 1 m/sec with protective cap
U23-002A: 15 seconds in air moving 1 m/sec
Drift
<1% per year typical
Logger
Operation Range
-40° to 70°C
-40° to 158°F
Real-time Clock
±1 minute per month 0° to 50°C
32° to 122°F
Battery
1/2 AA, 3.6 Volt lithium, user-replaceable (HP-B)
Battery Life (Typical Use)
3 years with 1 minute or greater logging interval
Memory (Non-Volatile)
64K bytes memory (approx. 21,000 temperature and RH measurements)
Materials
All models: ASA styrene polymer housing and mounting clamp; polypropylene protective cap; Buna-N o-ring(s); U23-001A,
U23-002A only: ASA styrene polymer RH sensor cap; modified hydrophobic polyethersulfone membrane
Cables
U23-001A: No cables
U23-002A: One 184 cm (6 ft) PVC cable; sensor diameter 1 cm (0.38 in.)
U23-003: Two 184 cm (6 ft) PVC cables; sensor diameter 0.5 cm (0.20 in.)
U23-004: One 184 cm (6 ft) PVC cable; sensor diameter 0.5 cm (0.20 in.)
Environmental Rating
Electronics housing is NEMA 6P equivalent (tolerant of brief submergence);
Units with RH sensors are NEMA 4 equivalent (splash-resistant)
Launch Modes
Immediate start; delayed start
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
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.
Weight
U23-001A: 57 g (1.5 oz); U23-002A: 118 g (3.1 oz); U23-003: 138 g (3.7 oz); U23-004: 102 g (2.7 oz)
Dimensions
Housing measures 10.2 × 3.8 cm
4.0 Ã 1.5 in.
NIST Certificate
Temperature certificate available for additional charge
