Data Logger

U23 Pro v2 External Temperature Data Logger

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.

External Temperature Data Logger

Diagram of data retrieval from U23 data logger using optic base station.

Image

Diagram showing installation of U23 data logger and solar radiation shield.

External Temperature Data Logger

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

External Temperature Data Logger

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

External Temperature Data Logger

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 × 1.5 in.

NIST Certificate

Temperature certificate available for additional charge

External Temperature Data Logger

External Temperature Data Logger

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U23 Pro v2 External Temperature Data Logger
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