Onset Hobo U12 User Manual

HOBO® U12 Temp/RH/Light/
External Data Logger
(Part # U12-012)

Inside this package:

• HOBO U12 Temp/RH/

Light/External Data Logger

• Mounting kit with magnet, hook

and loop tape, tie-wrap mount,
tie wrap, and two screws.

Doc # 7661-B, MAN-U12-012
Onset Computer Corporation

Thank you for purchasing a HOBO data logger. With proper care, it
will give you years of accurate and reliable measurements.

The HOBO U12 Temperature/Relative Humidity/Light/External Data
Logger is a four-channel logger with 12-bit resolution and can record
up to 43,000 measurements or events. The external channel accepts a
variety of sensors, including temperature, and split-core AC current
sensors as well as 4-20 mA and voltage input cables (sold separately).
The logger uses a direct USB interface for launching and data readout
by a computer.

An Onset software starter kit is required for logger operation. Visit
www.onsetcomp.com for compatible software.

Specifications

Temperature: -20° to 70°C (-4° to 158°F)

Measurement
range

Accuracy

Resolution

Drift

Response time
in airflow of 1
m/s (2.2 mph)

Time accuracy ± 1 minute per month at 25°C (77°F), see Plot C

Operating
temperature

Battery life 1 year typical use

Memory 64K bytes (43,000 12-bit measurements)

Weight 46 g (1.6 oz)

Dimensions 58 x 74 x 22 mm (2.3 x 2.9 x 0.9 inches)

RH: 5% to 95% RH
Light intensity: 1 to 3000 footcandles (lumens/ft

maximum value varies from 1500 to 4500 footcandles
(lumens/ft

External input channel (see sensor manual): 0 to 2.5 DC Volts

Temperature: ± 0.35°C from 0° to 50°C (± 0.63°F from 32° to
122°F), see Plot A

RH: ± 2.5% from 10 to 90%, see Plot B; conditions above
80% RH and 60°C (140°F) may cause additional error

Light intensity: Designed for indoor measurement of relative
light levels, see Plot D for light wavelength response

External input channel (see sensor manual): ± 2 mV ± 2.5% of
absolute reading

Temperature: 0.03°C at 25°C (0.05°F at 77°F), see Plot A
RH: 0.03% RH

Temperature: 0.1°C/year (0.2°F/year)
RH: <1% per year typical; RH hysteresis 1%

Temperature: 6 minutes, typical to 90%
RH: 1 minute, typical to 90%

Logging: -20° to 70°C (-4° to 158°F)
Launch/readout: 0° to 50°C (32° to 122°F), per USB

specification

The CE Marking identifies this product as complying with all
relevant directives in the European Union (EU).

2

)

2

) typical;

2. Plug the small end of the USB interface cable into the bottom of the
logger as shown in the following diagram.

Light
intensity
sensor

Important: Press this
button for 3 seconds
when logger is
launched with Button
Start or press for 1
second to record an
event while logging

USB interface
cable plugged
into logger

If the logger has never been connected to the computer before, it may take
a few seconds for the new hardware to be detected. Use the logger
software to launch and read out the logger.

Important: If you configure the logger to start with a button start, be
sure to press and hold down the button on the front of the logger for
at least three seconds when you want to begin logging.

If using an external sensor, be sure to plug it into the side of the logger
before logging begins. Also select the correct sensor and activate the
external channel in the logger software when configuring the launch.

Important: If you select an external channel, but do not plug the
probe in, false data will be recorded for that channel.

You can read out the logger 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.

Plot A Plot B

Plot C Plot D

Connecting the logger

The U-Family logger requires an Onset-supplied USB interface cable to
connect to the computer. If possible, avoid connecting at temperatures
below 0°C (32°F) or above 50°C (122°F).

1. Plug the large end of the USB interface cable into a USB port on the
computer.

Sample and event logging

The logger can record two types of data: samples and events. Samples are
the sensor measurements recorded at each logging interval (for example,
the temperature every minute). Events are independent occurrences
triggered by a logger activity. Examples of events recorded
asynchronously during deployment include when the logger is connected
to the host, when the battery is low, the end of a data file once the logger
is stopped, and button pushes.

Press the button on the front of the logger for one second to record an
event. Both a button up and down event will be recorded. This is useful if
you want to mark the datafile at a particular point. For example, if the
logger is located in an incubator, you might press the button each time the
door is opened.

The logger stores 64K of data, and can record up to 43,000 samples and
events combined.

Using external sensors

The external input channel has a switched 2.5 V output. This signal can be
used to power a sensor directly or it can also be used to trigger an external
circuit. An external sensor should draw no more than 4 mA total when
powered. The switched 2.5 V output turns on about 15 ms before the
external channel is measured and stays powered for 48 ms after it is
measured, as shown in the following diagram. The striped bar shows the
16 ms period during which the logger samples the input signal.

16 ms

15 ms

48 ms

© 2003, 2004 Onset Computer Corporation
Part #: MAN-U12-012, Doc #: 7661-B

HOBO U12 Temp/RH/Light/External Data Logger

Operation

A light (LED) on the side of the logger confirms
logger operation.

Channel 4
external
input

Light

The following table explains when the logger
blinks during logger operation.

When: The light:

The logger is logging Blinks once every one to four seconds (the

The logger is awaiting a start
because it was launched in Start
At Interval, Delayed Start, or
Button Start mode

The button on the logger is
being pushed for a Button Start
launch

shorter the logging interval, the faster the
light blinks); blinks when logging a sample

Blinks once every eight seconds until launch
begins

Blinks once every second while pressing the
button and then flashes rapidly once you
release the button. The light then reverts to a
blinking pattern based on the logging interval

Using the RH sensor

In order to take humidity measurements, the temperature sensor must be
used in conjunction with the RH sensor.

Conditions outside the recommended range may offset the RH signal.
Vapors may also affect the RH sensor. The diffusion of chemicals into the
sensor may cause a shift in both offset and sensitivity. High levels of
pollutants may cause permanent damage to the sensor.

Upon returning to normal conditions, the RH sensor will slowly return
towards calibration state by itself. However, prolonged exposure to
extreme conditions may accelerate aging and eventually lead to a
permanent shift. To recondition the sensor, do the following:

1. Remove the battery

2. Warm 24 hours 80–90°C (176–194°F) at < 5% RH

3. Re-hydrate 48 hours 20–30°C (70–90°F) at 75–95% RH

Protecting the logger

The logger can be permanently damaged by corrosion if it gets wet.
Protect it from condensation. If it gets wet, remove the battery
immediately and dry the circuit board with a hair dryer before reinstalling
the battery. Do not let the board get too hot. You should be able to
comfortably hold the board in your hand while drying.

Note! Static electricity may cause the logger to stop logging. To avoid
electrostatic discharge, transport the logger in an anti-static bag, and
ground yourself by touching an unpainted metal surface before handling
the logger. For more information about electrostatic discharge, visit
http://www.onsetcomp.com/Support/support.html.

Mounting

There are four ways to mount the logger using the materials in the
mounting kit included with the logger.

• Use the hook and loop tape to affix the

logger to a surface.

• Attach the magnet and then place the logger

on a magnetic surface.

• Use the tie wrap and tie wrap mount to tie

the logger to an object.

32 mm
(1¼ inch)

• Fasten the logger to a surface with the two

Phillips-head screws. The back of the logger
has two inserts for the screws, 32 mm (1¼
inches) apart.

Battery

The logger requires one 3-Volt CR-2032 lithium battery. Expected battery
life varies based on the temperature and the frequency at which the logger
is recording data (the logging interval). A new battery will typically last
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.

To replace the battery:

1. Disconnect the logger from the computer.

2. Unscrew the logger case.

3. Lift the circuit board and carefully push the battery out with a small
blunt instrument, or pull it out with your fingernail.

4. Insert a new battery, positive side facing up.

5. Carefully realign the logger case and re-fasten the screws.

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.

Service and Support

HOBO products are easy to use and reliable. In the unlikely event that you have a problem with
this instrument, contact the company where you bought the logger: Onset or an Onset
Authorized Dealer. Before calling, you can evaluate and often solve the problem if you write
down the events that led to the problem (are you doing anything differently?) and if you visit
the Technical Support section of the Onset web site at www.onsetcomp.com/support.html.
When contacting Onset, ask for technical support and be prepared to provide the product
number and serial number for the logger and software version in question. Also completely
describe the problem or question. The more information you provide, the faster and more
accurately we will be able to respond.

Onset Computer Corporation
470 MacArthur Blvd., Bourne, MA 02532
Mailing: PO Box 3450, Pocasset, MA 02559-3450
Phone: 1-800-LOGGERS (1-800-564-4377) or 508-759-9500
Fax: [phone]
E-mail: [e-mail]
Internet: www.onsetcomp.com

Returning Products to Onset

Direct all warranty claims and repair requests to place of purchase. Before returning a failed
unit, you must obtain a Return Merchandise Authorization (RMA) number from Onset. You
must provide proof that you purchased the Onset product(s) directly from Onset (purchase order
number or Onset invoice number). Onset will issue an RMA number that is valid for 30 days.
You must ship the product(s), properly packaged to protect against further damage, to Onset (at
your expense) with the RMA number marked clearly on the outside of the package. Onset is not
responsible for any package that is returned without a valid RMA number or for the loss of the
package by any shipping company. Products must be clean and free of any contaminants before
they are sent back to Onset or they may be returned to you.

Repair Policy

Products that are returned after the warranty period or that are damaged by the customer as
specified in the warranty provisions can be returned to Onset with a valid RMA number for
evaluation.

Optional Services

Please contact Onset for more information and prices on:

• ASAP Repair. Onset will expedite the repair of a returned product.

• Data-back™ Service. HOBO data loggers store data in nonvolatile EEPROM memory.

Onset will, if possible, recover your data to a disk.

• Tune Up Service. Onset will examine and retest any HOBO data logger.

Warranty

Onset Computer Corporation (“Onset”) warrants to the original end-user Purchaser for a period
of one year from the date of original purchase that the HOBO product(s) purchased will be free
from defect in material and workmanship. During the warranty period Onset will, at its option,
either repair or replace products that prove to be defective in material or workmanship.

This warranty is void if the product has been damaged by the Purchaser as a result of improper
maintenance, abuse, misuse, mishandling, misapplication, error or negligence of Purchaser, or if
there has been an unauthorized alteration, attachment or modification.

THERE ARE NO WARRANTIES BEYOND THE EXPRESSED WARRANTY AS
PROVIDED IN THIS DOCUMENT. IN NO EVENT SHALL ONSET BE LIABLE FOR
LOSS OF PROFITS OR INDIRECT, CONSEQUENTIAL, INCIDENTAL, SPECIAL OR
OTHER SIMILAR DAMAGES ARISING OUT OF ANY BREACH OF THIS
CONTRACT OR OBLIGATIONS UNDER THIS CONTRACT, INCLUDING BREACH
OF WARRANTY, NEGLIGENCE, STRICT LIABILITY, OR ANY OTHER LEGAL
THEORY.

LIMITATION OF LIABILITY. The Purchaser’s sole remedy and the limit of Onset’s

liability for any loss whatsoever shall not exceed the Purchaser’s price of the product(s). The
determination of suitability of products to the specific needs of the Purchaser is solely the
Purchaser’s responsibility. THERE ARE NO WARRANTIES BEYOND THE

EXPRESSED WARRANTY IN THIS DOCUMENT. EXCEPT AS SPECIFICALLY
PROVIDED IN THIS DOCUMENT, THERE ARE NO OTHER WARRANTIES
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO, ANY IMPLIED
WARRANTIES OF MERCHANTIBILITY OR FITNESS FOR A PARTICULAR
PURPOSE. NO INFORMATION OR ADVICE GIVEN BY ONSET, ITS AGENTS OR
EMPLOYEES SHALL CREATE A WARRANTY OR IN ANY WAY INCREASE THE
SCOPE OF THE EXPRESSED WARRANTY OFFERED WITH THE SALE OF THIS
PRODUCT.

INDEMNIFICATION. Products supplied by Onset are not designed, intended, or authorized

for use as components intended for surgical implant or ingestion into the body or other
applications involving life-support, or for any application in which the failure of the Onset­supplied product could create or contribute to a situation where personal injury or death may
occur. Products supplied by Onset are not designed, intended, or authorized for use in or with
any nuclear installation or activity. Products supplied by Onset are not designed, intended, or
authorized for use in any aeronautical or related application. Should any Onset-supplied product
or equipment be used in any application involving surgical implant or ingestion, life-support, or
where failure of the product could lead to personal injury or death, or should any Onset­supplied product or equipment be used in or with any nuclear installation or activity, or in or
with any aeronautical or related application or activity, Purchaser will indemnify Onset and
hold Onset harmless from any liability or damage whatsoever arising out of the use of the
product and/or equipment in such manner.

LEGAL REMEDIES. This warranty gives you specific legal rights. You may also have other
rights which vary by jurisdiction. The remedies provided herein are in lieu of all other remedies,
express or implied.

© 2003, 2004 Onset Computer Corporation. All rights reserved.
Part #: MAN-U12-012, Doc #: 7661-B

Onset and HOBO are registered trademarks of Onset Computer Corporation. Other products
and brand names may be trademarks or registered trademarks of their respective owners.

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