Highlighted 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
The U23-004 data logger supports the following measurement: Temperature
Temperature Sensor
Operation range internal sensors: -40° to 70°C (-40° to 158°F)
U23-002 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: ±0.21°C from 0° to 50°C (±0.38°F from 32° to 122°F); see Plot A
Resolution: 0.02°C at 25°C (0.04°F at 77°F); see Plot A
Response Time (typical to 90%)
U23-001 internal sensor: 40 minutes in air moving 1 m/sec
U23-002 external temperature sensor: 5 minutes 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
Stability (drift): < 0.1°C (0.18°F) per year
Relative Humidity Sensor (U23-001, U23-002 only)
Operation range: 0-100% 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. See Plot B for full range.
Resolution: 0.03%
Response Time (typical to 90%)
U23-001: 40 minute in air moving 1 m/sec with protective cap
U23-002: 5 minutes in air moving 1 m/sec with protective cap
Stability (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 (part # 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)
U23-001, U23-002 only: ASA styrene polymer RH sensor cap; modified hydrophobic polyethersulfone membrane
Cables
U23-001: No cables
U23-002: 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 (refer to HOBOware software manual)
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
U23-001: 57 g (1.5 oz)
U23-002: 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 × 1.5 in.)
NIST certificate: Temperature certificate available for additional charge
The CE Marking identifies this product as complying with the relevant directives in the European Union (EU).
