HOBO Pendant Temperature/Light Data Logger (UA-002

HOBO® Pendant® Temperature/Light
Data Logger (UA-002-xx) Manual
The HOBO Pendant Temperature/Light Data Logger is a waterproof, two-channel logger with
10-bit resolution and can record up to approximately 3,500 (8K model) or 28,000 (64K model)
combined temperature and light readings or internal logger events. The logger uses a coupler
and optical base station with USB interface for launching and data readout by a computer.
HOBO Pendant
Data Logger
Models: UA-002-08
Required Items:
• HOBOware 2.x or later
• USB cable (included with
• Pendant Optic USB Base
Station & Coupler (BASE-U-1)
• Optic USB Base Station
(BASE-U-4) or HOBO
Waterproof Shuttle
(U-DTW-1) & Coupler
Measurement Range
Temperature: -20° to 70°C (-4° to 158°F)
Light: 0 to 320,000 lux (0 to 30,000 lumens/ft )
Temperature: ± 0.53°C from 0° to 50°C (± 0.95°F from 32° to 122°F), see
Plot A
Light intensity: Designed for measurement of relative light levels, see Plot D
for light wavelength response
Temperature: 0.14°C at 25°C (0.25°F at 77°F), see Plot A
Less than 0.1°C/year (0.2°F/year)
Response Time
Airflow of 2 m/s (4.4 mph): 10 minutes, typical to 90%
Water: 5 minutes, typical to 90%
Time Accuracy
±1 minute per month at 25°C (77°F), see Plot B
Operating Range
In water/ice: -20° to 50°C (-4° to 122°F)
In air: -20° to 70°C (-4° to 158°F)
Water Depth Rating
30 m from -20° to 20°C (100 ft from -4° to 68°F), see Plot C
NIST Traceable
Available for temperature only at additional charge; temperature range
-20° to 70°C (-4° to 158°F)
Battery Life
1 year typical use
UA-002-08: 8K bytes (approximately 3.5K combined temperature and light
readings or events)
UA-002-64: 64K bytes (approximately 28K combined temperature and light
readings or events)
Polypropylene case; stainless steel screws; Buna-N o-ring
18 g (0.6 oz)
58 x 33 x 23 mm (2.3 x 1.3 x 0.9 inches)
The CE Marking identifies this product as complying with all relevant
directives in the European Union (EU).
Plot A
9556-K MAN-UA-002
Plot B
HOBO Pendant Temperature/Light Data Logger (UA-002-xx) Manual
Specifications (continued)
Response (%)
Depth (m)
Temperature (°C)
Wavelength (nm)
Plot C
Plot D
1. Plug the USB connector on the base station into an available
USB port on your computer.
The Light Sensor response is roughly cosine dependent with the
angle from vertical. Therefore, whether outdoors or
underwater, the logger must be mounted horizontally so that
the sensor is pointing straight up towards the sky.
2. Insert the logger and the base station into the coupler, as
shown in the following diagrams.
For BASE-U-1, make sure that the logger is inserted in the
end of the coupler that has the magnet, and that the ridges
on the base station and logger are aligned with the grooves
in the coupler.
Attach the logger to a flat surface using glue, a tie, or a rubber
band, making sure that the sensor is pointing up.
For BASE-U-4 or the HOBO Waterproof Shuttle, firmly insert
the optical end of the base station into the D-shaped end of
the coupler, and make sure that the ridge on the logger is
aligned with the groove in the coupler.
To BASE-U-4 or
HOBO Waterproof Shuttle
Connecting the Logger to a Computer
The HOBO Pendant logger requires either of the following to
connect to the computer:
Ridge side down
• Pendant Optic USB Base Station & Coupler (BASE-U-1);
HOBOware 2.1 or later
3. If you are using the HOBO Waterproof Shuttle, briefly press
the coupler lever to put the shuttle into base station mode.
• Optic USB Base Station (BASE-U-4) or HOBO Waterproof
Shuttle (U-DTW-1); coupler (COUPLER2A); HOBOware 2.2 or
4. If the logger has never been connected to the computer
before, it may take a few seconds for the new hardware to
be detected.
If possible, avoid connecting at temperatures below 0°C (32°F)
or above 50°C (122°F).
Coupler lever (for use with
HOBO Waterproof Shuttle)
HOBO Pendant Temperature/Light Data Logger (UA-002-xx) Manual
5. Use the logger software to set up the alarms, launch, and
read out the logger.
Light Measurement
The logger measures light intensity in units of lumens per
square foot (US) or lux (SI). The light sensor in the Pendant
logger measures a much broader spectrum of light wavelengths
than are visible to the human eye. Plot D shows that the
logger's response extends farther into ultraviolet and infrared
wavelengths than the eye's response. This means the logger is
useful for sensing wavelengths not visible to the eye, but it also
may mean that the logger's readings will not correspond
exactly to measurements made with a device having different
spectral sensitivity. The light sensor is most useful for
determining relative changes, rather than absolute values of
You can read out the logger or check its status while it
continues to log, stop it manually with the software, or let it
record data until the memory is full. Refer to the software
user’s guide for complete details on launching, reading out, and
viewing data from the logger.
Important: Do not cover the optical communication window in
the logger (shown in diagram above) with a label or sticker as
that may interfere with the communications with the base
station or shuttle.
Triggered Start
The logger has a very wide dynamic range of light sensitivity
extending from complete darkness to somewhat beyond full
daylight. The resolution steps are smaller at low light levels
than at high light levels to allow useful measurements across
this broad range of intensities. Intensity readings are maximum
for light hitting the sensor directly on-axis and are reduced for
light coming in at an angle. Readings can also be reduced by
abrasions or dirt on the case above the light sensor.
This logger can be configured to start at your command, using
the magnet in the coupler to trigger a start.
1. Use HOBOware to launch the logger with Using Coupler
selected. Remove the logger from the coupler.
2. Bring the logger and an empty coupler or strong magnet to
the deployment location.
Important: Any magnet can trigger a start. This can be helpful,
but it can also cause a premature start. Keep the logger away
from strong magnetic fields until you are ready to begin
Protecting the Logger
The logger can be damaged if the water depth rating is
exceeded. The depth rating is approximately 30 m (100 ft) at
temperatures below 20°C (68°F), but is less in warmer water.
Refer to Plot C for details.
3. When you are ready for the logger to start logging, insert
the logger into the empty coupler (or place it next to a
strong magnet) and remove it after three seconds.
Do not store the logger in the coupler. Remove the logger from
the coupler when you are not using it. When the logger is in the
coupler or near a magnet, it consumes more power and will
drain the battery prematurely.
Important: The logger will not launch if the base station is in
the coupler.
Keep the logger away from magnets. Being near a magnet can
cause false coupler events to be logged. It can also launch the
logger prematurely if it was waiting for a trigger start.
4. Verify that the logger’s light is blinking at least every four
Note! Static electricity may cause the logger to stop logging.
To avoid electrostatic discharge, transport the logger in an antistatic bag, and ground yourself by touching an unpainted metal
surface before handling the logger. For more information,
search for “static discharge” in the FAQ section on
Sample and Event Logging
The logger can record two types of data: samples and internal
logger events. Samples are the measurements recorded at each
logging interval (for example, temperature every minute). Events
are independent occurrences triggered by a logger activity, such
as Bad Battery or Host Connected. Events help you determine
what was happening while the logger was logging.
Periodically inspect the desiccant and dry it if it is not bright
blue. The desiccant pack is located in the cap of the logger. To
dry the desiccant, remove the desiccant pack from the cap and
leave the pack in a warm, dry location until the bright blue
color is restored. (Refer to the Battery section for instructions
on removing and replacing the logger cap.)
A light (LED) on the front of the logger confirms logger
operation. The following table explains when the light blinks
during logger operation.
Temperature Range
Desiccant Maintenance Schedule
The light:
Less than 30°C (86°F)
Approximately once per year
The logger is logging
Blinks once every one to four seconds
(the shorter the logging interval, the
faster the light blinks); blinks when
logging a sample
30° to 40°C (86° to
Approximately every six months
Over 40°C (104°F)
Approximately every three months
The logger is awaiting a start
because it was configured to
start logging At Interval, On
Date/Time, or Using Coupler
Blinks once every eight seconds until
logging begins
HOBO Pendant Temperature/Light Data Logger (UA-002-xx) Manual
The logger requires one 3-Volt CR-2032 lithium battery. Battery
life varies based on the temperature and the frequency at
which the logger is recording data (the logging interval). A new
battery typically lasts one year with logging intervals greater
than one minute. Deployments in extremely cold or hot
temperatures, or logging intervals faster than one minute, may
significantly reduce battery life. Continuous logging at the
fastest logging rate of one second will deplete the battery in as
little as two weeks.
8. Remove the O-ring from the end cap. Use the thumb and
finger of one hand to hold the cap from the top and
bottom, and use the thumb and fingers on your other hand
to slide the O-ring to form a loop as shown. Use this loop to
roll the O-ring off the cap.
Replacing the Battery
Before you begin: You will need a small Philips head
screwdriver and silicone-based O-ring grease, such as Parker
Super-O-Lube, to complete these steps (no petroleum-based
lubricants). The logger should be wiped clean and dried
completely before opening it.
To replace the battery:
1. Avoid electrostatic discharge while handling the logger and
internal circuit board; ground yourself by touching an
unpainted metal surface. Hold the circuit board by its edges
and avoid touching electronics.
2. Working on a clean, dry surface, remove the two screws
that secure the end cap to the case and remove the cap.
3. Examine the desiccant pack that is tucked into the cap. If
the desiccant is not bright blue, put the desiccant pack in a
warm, dry place until the blue color is restored. Or, for
faster drying, the desiccant can be dried for two hours in a
70°C (160°F) oven.
4. Gently tap the case to loosen the circuit board and remove
it from the case.
9. Inspect the O-ring for cracks or cuts and replace it if any are
detected (the O-ring is included in the Pendant replacement
parts kit, UA-PARTSKIT).
10. Using your fingers (not cloth or paper), spread a small dot of
silicone-based grease on the O-ring, just enough to moisten
it all the way around and making sure that the entire O-ring
surface is completely coated with grease. As you work the
grease into the O-ring, make sure there is no grit or debris
on the O-ring.
11. Place the O-ring back on the end cap, making sure it is fully
seated and level in the groove. Make sure the O-ring is not
pinched or twisted and that no dirt, lint, hair, or any debris
is trapped on the O-ring. This is necessary to maintain a
waterproof seal.
12. Very slightly grease the inside rim of the case, especially
around the screw holes with the silicone grease, just
enough to moisten the inside edges without touching any
circuitry. Make sure that there is no excess lubricant that
could get onto the logger electronics or label. Make sure
there is no debris on this surface.
13. Check that the desiccant pack is tucked into the cap.
14. Carefully push the end cap into the lubricated case until the
screw holes are aligned. Visually check that the O-ring forms
a uniform seal all around.
O-ring on end cap, with
desiccant tucked inside
Circuit board
Logger case
5. Carefully push the battery out of the holder with a small,
nonmetallic blunt instrument.
6. Insert a new battery, positive side facing up.
7. Return the circuit board and label to the case, carefully
aligning the circuit board with the grooves in the case so
that the battery faces the ridged side of the case.
1-800-LOGGERS (564-4377) • 508-759-9500
www.onsetcomp.com • loggerhelp@onsetcomp.com
15. Re-fasten the screws. Tighten the screws until you feel
them hit the bottom of the screw holes, but not so tight
that they distort the clear housing.
WARNING: Do not cut open, incinerate, heat above
85°C (185°F), or recharge the lithium battery. The battery
may explode if the logger is exposed to extreme heat or
conditions that could damage or destroy the battery case. Do
not dispose of the logger or battery in fire. Do not expose the
contents of the battery to water. Dispose of the battery
according to local regulations for lithium batteries.
© 2009–2014 Onset Computer Corporation. All rights reserved. Onset, HOBO, Pendant, and
HOBOware are trademarks or registered trademarks of Onset Computer Corporation. All other
trademarks are the property of their respective companies.
Patent # 6,826,664
9556-K MAN-UA-002
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