HOBO 2x External Temperature Data Logger
HOBO data loggers require HOBOware software and a USB cable. (Note: A USB cable is included w/HOBOware Pro CD or USB software purchase). HOBOware Pro is required when using the U-DTW-1 Waterproof shuttle. See compatible items below.
Overview
The HOBO Pro v2 2x External Temperature Data Logger is a weatherproof data logger with two external soil/water temperature probes on 6-foot cables for fast sensor response and deployment in tight spaces.
- 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
In what environment does this data logger operate?
This data logger operates in an outdoor environment.
What measurements does this data logger support?
The U23-003 data logger supports the following measurements: Soil Temperature and Temperature
The country of origin for this product is the United States. To see the full specifications for this product, please see our product manual found under the documentation tab if available.
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 Ă— 3.8 cm (4.0 Ă— 1.5 in.) |
NIST Certificate | Temperature certificate available for additional charge |
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The CE Marking identifies this product as complying with all relevant directives in the European Union (EU). |

- HOBO U23-003 2x External Temp Data Logger
- Clamp and mounting screws
- UV protective cap
The following are associated resources for this product. In general users of this product can gain insight into its possible use by utilizing the resources below.
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Detailed Specifications
HOBO 2x External Temperature Data Logger
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 Ă— 3.8 cm (4.0 Ă— 1.5 in.) |
NIST Certificate | Temperature certificate available for additional charge |
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The CE Marking identifies this product as complying with all relevant directives in the European Union (EU). |