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Specifications
LCD
Size
Elements
Alarms
Set points
Reset options
Selectable Contact Relay
Contact rating
Contact resistance
Range
Communications
Method
Speed
Time accuracy
Power
Dimensions
Weight
Internal 12‐Bit Temperature Sensor
Measurement range
Accuracy
Resolution
Response time
Temperature Accuracy Drift
Internal 12‐Bit Relative Humidity Sensor (User replaceable)
Measurement range
Accuracy
Resolution
Response time
Accuracy Drift
Hysteresis
External Sensors
Battery Life
Temperature Accuracy and Resolution
The maximum reading error for the internal temperature sensors is shown at right. This is a worst case
error. In a typical logger, temperature errors will be substantially lower. NIST certification of
temperature accuracy for some sensors is available from Onset. The temperature resolution for internal
sensors is also shown at right. Resolution is the smallest difference between adjacent temperature steps
that the logger can report. The logger will typically experience little or no accuracy drift unless the
electronic components or temperature sensor are damaged mechanically or by exposure to
environmental factors beyond the specifications, such as high heat and humidity.
HOBO U14 Data Logger User Manual
33 x 50.8 mm (1.3 x 2 inches)
Temperature and relative humidity simultaneously
°C or °F (selectable within host software)
Memory remaining and battery level
Flashing ALERT for out‐of‐limits conditions (selectable within host software), which stops flashing
on offload or return to normal range
High and low set points for both temperature and relative humidity with selectable delays
Alert conditions reset on offload or return to normal range
Normally Closed or Normally Open
48VDC, 1A max
Less than 1 Ohm
0% Low Battery Range
Offloads data to PC or U‐Shuttle via USB cable
Readout full logger (64K) in less than 30 seconds
±1 minute per month at +20°C (+68°F)
3 AAA Alkaline batteries, user‐replaceable
125 x 92 x 31 mm (4.9 x 3.6 x 1.2 in)
170 g (6.0 oz) with batteries
‐20°C to +50°C (‐4°F to +122°F)
±0.21°C from 0° to 50°C (±0.38°F from 32° to 122°F); ±0.13°C (0.24°F) typical (see Plot A)
0.02°C @ 25°C (0.04°F @ 77°F) (see Plot A)
15 minutes (to 90% in airflow of 1 m/sec)
Negligible
0‐100% RH, ‐20 to 50°C (‐4 to 122°F)
+/‐ 2.5% from 10% to 90% RH (typical), to a maximum of +/‐ 3.5% including hysteresis (see Plot B)
0.03% RH @ 25°C (77°F)
2 minutes (to 90% in airflow of 1 m/sec)
<2% over 5 years typical
1% Typical
For External Sensor Specifications, see the sensor's user manual
The batteries will last one year in typical conditions (logging intervals of ≥ 1 minute with weekly
offloads and average temperatures greater than 10°C or +50°F). Frequent offloads and/or extreme
temperatures will reduce battery life. At temperatures below freezing (0°C or +32°F), batteries will
typically require replacement every six months. In these conditions the battery level bar graph
should be checked regularly. See Battery Level Indicators on page 8.
The CE Marking identifies this product as complying with all relevant directives in the European
Union (EU).
Plot A: Internal Temperature Sensor
2
Accuracy and Resolution
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