Onset HOBO User manual

HOBO® 4-Channel Analog Data Logger (UX120-006M) Manual
The HOBO 4-Channel Analog data logger has 16-bit resolution and can record up to 1.9 million
measurements or events. The four external channels accept a variety of sensors, including
temperature and split-core AC current sensors as well as 4-20 mA and voltage input cables (sold
separately). Using HOBOware®, you can easily configure an alarm to trip when the sensor
reading rises above or falls below a measurement that you specify. Or, you can set up burst
logging in which the logger records data at a different interval during certain conditions. The
logger can also calculate minimum, maximum, average, and standard deviation statistics. This
easy-to-use data logger has a built-in LCD screen to check current readings and to monitor
logging status, battery use, and memory consumption in between readouts.
Specifications
Logger with
Cable Type
CABLE-
4-20mA
CABLE-2.5-
STEREO
CABLE-
ADAP5
CABLE-
ADAP10
CABLE-
ADAP24
Measurement
Range
0 to 20.1 mA 0 to 2.5 V 0 to 5.0 V 0 to 10 V 0 to 24 V
Accuracy ±0.001 mA
±0.2% of
reading
±0.1 mV
±0.1% of
reading
±0.2 mV
±0.3% of
reading
±0.4 mV
±0.3% of
reading
±1.0 mV
±0.3% of
reading
Resolution 0.3 µA 40 µV 80 µV 160 µV 384 µV
Logger
Operating Range Logging: -20° to 70°C (-4° to 158°F); 0 to 95% RH (non-condensing);
Launch/Readout: 0° to 50°C (32° to 122°F) per USB specification
Logging Rate 1 second to 18 hours, 12 minutes, 15 seconds
Logging Modes Normal, burst, or statistics
Memory Modes Wrap when full or stop when full
Start Modes Immediate, push button, date & time, or next interval
Stop Modes When memory full, push button, or date & time
Restart Mode Push button
Time Accuracy ±1 minute per month at 25°C (77°F), see Plot A
Battery Life 1 year, typical with logging rate of 1 minute and sampling interval of 15
seconds or greater
Battery Type Two AAA 1.5 V alkaline batteries, user replaceable
Memory 4 MB (1.9 million measurements, maximum)
Download Type USB 2.0 interface
Full Memory Download
Time
Approximately 1.5 minutes
LCD LCD is visible from 0° to 50°C (32° to 122°F); the LCD may react slowly or
go blank in temperatures outside this range
Size 10.8 x 5.41 x 2.54 cm (4.25 x 2.13 x 1 in.)
Weight 107.5 g (3.79 oz)
Environmental Rating IP50
The CE Marking identifies this product as complying with all relevant
directives in the European Union (EU).
HOBO 4-Channel Analog
Data Logger
UX120-006M
Included Items:
Command™ strip
Double-sided tape
Hook & loop strap
Two AAA 1.5 V alkaline
batteries
Required Items:
HOBOware 3.6 or later
USB cable (included with
software)
Sensors and cables available at
www.onsetcomp.com.

HOBO 4-Channel Analog Data Logger (UX120-006M) Manual
Specifications (continued)
Plot A: Time Accuracy
Logger Components and Operation
Start/Stop Button: Press this button for 3 seconds to start or
stop logging data, or to resume logging. This requires
configuring the logger in HOBOware with a push button start or
stop, and with “Resume logging on next button push” selected
(see Setting up the Logger). You can also press this button for
1 second to record an internal event (see Recording Internal
Logger Events) or to turn the LCD screen on if the option to turn
off the LCD has been enabled (see Setting up the Logger).
Alarm/Stats Button: Use this button to clear a tripped alarm
(see Setting up Alarms) or to switch between statistics, alarm
readings, and the current sensor reading.
Mounting Loops: Use the two mounting loops (only one visible
in the diagram) to mount the logger with the hook-and-loop
strap (see Mounting the Logger).
External Inputs: Use these 2.5 mm jacks (not visible in the
diagram) to connect up to 4 sensors (see Connecting External
Sensors).
USB Port: Use this port to connect the logger to the computer
or the HOBO U-Shuttle via USB cable (see Setting up the Logger
and Reading Out the Logger).
LCD Screen: This logger is equipped with an LCD screen that
displays details about the current status. This example shows all
symbols illuminated on the LCD screen followed by definitions
of each symbol in the table.
LCD Symbol Description
The logger is waiting to be launched. Press and
hold the Start/Stop button for 3 seconds to launch
the logger.
The logger has been launched with push button
stop enabled; press and hold the Start/Stop
button for 3 seconds to stop the logger. Note : If
you also launched the logger with a push button
start, this symbol will not appear on the display for
30 seconds.
An alarm is ready to be cleared. This will only
appear if “Cleared with button press” was selected
in the HOBOware alarm settings. Press the
Alarm/Stats button for 3 seconds to clear the
alarm.
The battery indicator shows the approximate
battery power remaining.
This is an example of a temperature reading from
a temperature sensor. Temperature units are
determined by the settings in HOBOware. To
switch between Celsius and Fahrenheit, change
the Display Preferences in HOBOware before
launching the logger.
A sensor reading is above or below the high or low
alarm that you configured. Press and release the
Alarm/Stats button until the “alm” symbol
(described later in this chart) is displayed on the
screen. This symbol at left will clear depending on
how alarms were configured in HOBOware. If the
alarm was configured to clear when the logger is
relaunched, this symbol will remain on the LCD.
Otherwise, it will clear when the sensor reading is
back within the alarm limits or by pressing the
Alarm/Stats button for 3 seconds.
This is the channel number associated with the
sensor reading (channel 1 for this example). Up to
four channels are visible at one time.
This is an example of the units entered for the
sensor, which appears to the right of the channel
number. The unit type is determined by what was
entered in the LCD Units field for that sensor in
HOBOware. See Setting up the Logger for more
details. Note that units for temperature sensors
are displayed as °F or °C only.
The logger has been configured to start logging on
a particular date/time. The display will count down
in days, hours, minutes, and seconds until logging
Alarm/Stats Button
Start/Stop Button
USB Port
Mounting Loop
LCD Screen
External Inputs

HOBO 4-Channel Analog Data Logger (UX120-006M) Manual
LCD Symbol Description
begins. In this example, 5 minutes and 38 seconds
remain until logging will begin.
The logger is currently logging.
The logger has been configured to stop logging
when memory fills. The memory bar indicates the
approximate space remaining in the logger to
record data. When first launched, all five segments
in the bar will be empty. In this example, the
logger memory is almost full (only one segment in
the memory bar is empty).
The logger has been configured to never stop
logging (wrapping). The logger will continue
recording data indefinitely, with newest data
overwriting the oldest data. When first launched,
all five segments in the memory bar will be empty.
In this example, the memory is full (all five
segments are filled in) and new data is now
overwriting the oldest data. This will continue until
the logger is stopped or the battery runs out.
These symbols show the maximum, minimum,
average, and standard deviation values most
recently calculated by the logger (if the logging
mode has been set to Statistics in HOBOware).
Press the Alarm/Stats button for 1 second to cycle
through each of the available statistics, any alarm
readings, and back to the current sensor reading.
This is the sensor reading that tripped the alarm.
Press the Alarm/Stats button to view this reading.
Press the Alarm/Stats button again to cycle
through any statistics and return to the current
readings.
The launch settings are being loaded onto the
logger from HOBOware. Do not disconnect the
USB cable during this process.
An error occurred while loading the launch
configurations onto the logger from HOBOware.
Make sure the USB cable is connected to both the
logger and the computer and try launching again.
The logger has been stopped with HOBOware or
because the memory is full.
Notes:
 You can disable the LCD screen when logging. Select
“Turn LCD off” when setting up the logger as described in
the next section. When this option is enabled, you can
still temporarily view the LCD screen by pushing the
Start/Stop button for 1 second. The LCD will then remain
on for 10 minutes.
 The LCD screen refreshes every 15 seconds while logging
regardless of the logging interval selected in HOBOware.
If you choose a logging interval less than 15 seconds, the
data will be recorded at the faster interval, but the sensor
readings will only be updated on the screen every 15
seconds.
 If a sensor is disconnected during logging, erroneous
values will display for that sensor on the LCD and return
to normal readings once reconnected. See Connecting
External Sensors for more details.
 When the logger has stopped logging, the LCD screen will
remain on until the logger is offloaded to a computer or
HOBO U-Shuttle (unless launched with the “Turn LCD off”
option). Once the logger has been offloaded and
disconnected from the computer, the LCD will turn off
automatically after 2 hours. The LCD will turn back on the
next time the logger is connected to the computer.
Setting up the Logger
Use HOBOware to set up the logger, including setting alarms,
selecting the options to start and stop logging, and choosing a
logging mode.
1. Install the batteries. See Battery Information for details.
2. Connect the logger and open the Launch Logger window.
To connect the logger to a computer, use the USB cable
provided. Click the Launch icon on the HOBOware toolbar
or select Launch from the Device menu.
Important: USB 2.0 specifications do not guarantee
operation outside the range of 0°C (32°F) to 50°C (122°F).
3. Configure a sensor. Under Configure Sensors to Log, click
the checkbox for sensor 1. Select the type of sensor or cable
that will be connected to channel 1 on the logger. Type a
label for the sensor if desired. Be sure to connect the sensor
before logging begins.
4. Set up scaling (optional). You can configure some sensors
to scale logged data into different values and units than the
default. If the sensor supports scaling, click the Scaling
button and type in the appropriate values and units (consult
the sensor user manual for recommended scaling factors).
Click Save and return to the Launch Logger window.
5. Set the LCD units (optional). Each sensor has its own
default units that will appear on the logger LCD. Type in up
to 3 characters if you want a different unit name to appear
on the LCD than the default. (Units for temperature sensors
are F or C and cannot be changed.) Note that if you have
configured Scaling for the sensor, then the scaled units
name will appear in the Launch Logger window for the
sensor instead of its default unit. You can still override this
by entering a new name in the LCD units field.
6. Set up alarms (optional). Click the Alarms button if you
want to configure an alarm to trip when the sensor reading
is above or below a value you specify. See Setting up Alarms
for details.

HOBO 4-Channel Analog Data Logger (UX120-006M) Manual
7. Configure filters (optional). Click the Filters button to
create additional filtered data series. Any filtered series will
be available automatically upon reading out the logger.
8. Configure additional sensors. Repeat steps 3 through 7 to
configure up to three more sensors.
9. Select the Logging Interval. Select a logging interval from 1
second to a maximum of 18 hours, 12 minutes, and 15
seconds.
10. Select the Logging Mode:
 Normal. In Normal mode, data will always be recorded at
the regular logging interval set in the previous step. This
is the default setting.
 Burst. In Burst mode, logging will occur at a different
interval when a specified condition is met. See Burst
Logging for more information.
 Statistics. In Statistics mode, maximum, minimum,
average, and standard deviation statistics are calculated
for the temperature during logging, sampling at an
interval you specify. See Statistics for more information.
11. Choose when to start logging:
 Now. Logging begins immediately.
 At Interval. Logging will begin at the next even interval as
determined by the selected logging interval.
 On Date/Time. Logging will begin at a date and time you
specify.
 Push Button. Logging will begin once you press the
Start/Stop logging button for 3 seconds.
12. Choose when to stop logging:
 When Memory Fills. Logging will end once the logger
memory is full.
 Never (Wrapping). The logger will continue recording
data indefinitely, with newest data overwriting the
oldest.
 Push Button. Logging will end once you press the
Start/Stop logging button for 3 seconds. If you select
Push Button, you also have the option to select “Resume
logging on next button push.” Select this if you want to
be able to start and stop logging at any time during the
deployment by pushing the Start/Stop button on the
logger. Note that if you also choose Push Button to start
logging, then you will not be able to stop logging until 30
seconds after logging begins.
 Specific Stop Time. Logging will end at a date and time
you specify. Note that if you also configure the logger for
a Push Button stop and to “Resume logging on next
button push,” then the logger will stop logging at the
date you select regardless of how many times you stop
and restart the logger with the Start/Stop button.
13. Choose whether to keep the LCD on or off. By default, the
LCD will always remain on while logging. If you select the
“Turn LCD off” checkbox, the LCD will not show the current
readings, status, or other information while the logger is
logging. You will, however, be able to temporarily turn the
LCD screen on by pressing the Start/Stop button for 1
second if you select this option.
14. Click the Start button to launch the logger. Note that the
Start button text changes based on the Start Logging
selection. Disconnect the logger from the computer and
deploy it using the mounting materials (see Mounting the
Logger). After logging begins, you can read out the logger at
any time (see Reading Out the Logger for details).
Connecting External Sensors
The logger can accept up to four external sensors (refer to
onsetcomp.com for a current list of supported sensors). Plug
each sensor into one of the four input jacks, making sure each
sensor is firmly seated in the appropriate numbered jack based
on how you configured that corresponding channel in the
Launch Logger window. For example, if you selected “TMCx-
HD” for sensor 1 in the Launch Logger window, then you must
plug the TMCx-HD temperature sensor into the port labeled “1”
on the logger otherwise the logger will not record the correct
data. Connect each sensor before logging begins. Refer to the
sensor or cable manual for more information on connecting the
sensor and wiring, if applicable.
If you disconnect a sensor or if it is not fully inserted into the
jack while the logger is logging, an erroneous sensor reading
can appear on the LCD for that channel. In addition, erroneous
readings will be logged and saved in the data file depending on
the logging interval (e.g. if a sensor is disconnected for 5
minutes and the logging interval is set to 1 minute, then there
will be 5 erroneous data points while the sensor was
disconnected). If you reconnect the sensor, the correct values
will display on the LCD again and will be logged and saved in
the data file.
Some sensors, such as temperature sensors, can be connected
directly to the external input jacks, but others require
additional cables as described in the following sections.
4-20mA Input Cable
The 4-20mA input cable (CABLE-4-20mA) measures current
from 0 to 20.1 mA. Do not expose to current above 20 mA or to
negative current. Do not cut off the end of the gray cable where
it connects to the blue and yellow wires as it contains the
precision resistor required for current measurement.
Voltage Input Cable
The logger’s external inputs can accept the voltage input cable
(CABLE-2.5-STEREO), which allows a voltage to be recorded.
The input line must not be exposed to signals below 0 V or
above 2.5 V. The voltage input cable connections are as follows:
Wire Connection
Red Switched 2.5 V output
White Voltage input
Black Ground

HOBO 4-Channel Analog Data Logger (UX120-006M) Manual
Switched 2.5 V Output
The external input channels have a switched 2.5 V output. This
signal can be used to power a sensor directly or to trigger an
external circuit. External sensors should draw no more than 4
mA total when powered.
The switched 2.5 V output turns on about 5 ms before the
external channels are measured as shown in the following
diagram. The shaded area shows the 100 ms period for each
enabled channel during which the logger samples the input
signals.
When using multiple voltage and/or current inputs, the (-) from
the current source(s) and the 0 V line from the voltage
source(s) are tied together at the logger. If these lines are at
different voltage potentials, this may cause inaccurate readings
or even damage your logger. Keep in mind that these lines may
also be tied to earth ground through the USB cable when the
logger is connected to the computer. Special precautions may
be necessary if any of the voltage or current source common
lines are not tied to earth ground. Input isolators may be
needed in industrial environments to prevent errors caused by
ground loops.
WARNING: Analog channel input cannot exceed 2.5 V DC.
For sensor outputs up to 24 V DC, use the appropriate voltage
adapter cable (CABLE-ADAPX).
Setting up Alarms
You can set an alarm to trip when a sensor reading rises above
or falls below a specified value on any of the four sensor
channels. To set an alarm:
1. Click the Alarms button from the Launch Logger window. If
the Alarms button is disabled, make sure the Logging Mode
is not set to Burst. (Alarms can only be configured if the
logger is in Normal or Statistics mode.)
2. In the Configure Alarms window, select a sensor from the
list. In the example in this section, a temperature sensor
was selected.
3. Select the High Alarm checkbox if you want an alarm to trip
when the sensor reading rises above the high alarm value.
Type the reading next to the High Alarm checkbox or drag
the red upper slider in the Configure Alarms window.
4. Select the Low Alarm checkbox if you want an alarm to trip
when the sensor reading falls below the low alarm value.
Type the reading next to the Low Alarm checkbox or drag
the blue lower slider.
5. Set the “Number of out-of-range samples displayed before
alarm is raised,” which is the number of sensor readings
needed to trigger each alarm. The time next to the “Number
of out-of-range…” field indicates the amount of time it will
take for the alarm to trip based on the number you entered
in that field and the 15-second LCD refresh rate.
6. Select either Cumulative or Consecutive for the Sensor
Alarm Mode. If you select Cumulative, the alarm will trip
after a specific number of samples (as set in the previous
step) are outside the limits (the high or low samples do not
need to be consecutive). If you select Consecutive, the
alarm will trip after a specific number of samples (as set in
the previous step) outside the limits are displayed in a row.
7. Repeat steps 2 through 6 for any additional sensors.
8. Choose how long the logger should maintain the sensor
alarm once it has tripped. Select “Host has relaunched
logger” if you want the alarm to remain visible on the LCD
until the next time you relaunch the logger. Select “Sensor
reading within limits” if you want the alarm to clear once
the sensor reading returns to the normal range between
the high and low alarm limits. Select “Cleared with button
press” if you want the alarm to remain on until you press
the Alarm/Stats button on the logger.
9. Click OK to save alarm settings.
Notes:
 Once the logger is launched, alarms will trip as
determined by these settings. Logger alarms will display
on the LCD screen. Note that the alarm limits are only
checked when the logger’s LCD screen refreshes every 15
seconds.
 The actual values for the high and low alarm limits are set
to the closest values supported by the logger based on
the sensor type. This means the value that triggers the
alarm may differ slightly than the value entered.
 When you read out the logger, high and low alarm levels
will be displayed on the plot along with “Chan <#> Alarm
Tripped” and “Chan <#> Alarm Cleared” events showing
when the alarm tripped and cleared. The “Chan <#>
Alarm Cleared” event contains the value that was
furthest out of range for the sensor before the alarm
cleared (see the Points table for the actual value).

HOBO 4-Channel Analog Data Logger (UX120-006M) Manual
Burst Logging
Burst logging is a logging mode that allows you to set up more
frequent logging when a specified condition is met. For
example, let’s say the logger has a temperature sensor
connected to channel 1 and is recording data at a 5-minute
logging interval. Burst logging is configured on channel 1 to log
every 10 seconds when the temperature goes above 85°F (the
high level) or falls below 32°F (the low level). This means the
logger will record data every 5 minutes as long as the
temperature remains between 85°F and 32°F. Once the
temperature reaches 90°F, for example, the logger will switch
to the faster logging rate and record data every 10 seconds
until the temperature falls back below the high level (or 85°F in
this case). At that time, logging then resumes every 5 minutes
at the normal logging interval. Similarly, if the temperature falls
to 30°F, for example, then the logger would switch to burst
logging mode again and record data every 10 seconds. Once the
temperature rises back to 32°F, the logger will then return to
normal mode, logging every 5 minutes. To set up burst logging:
1. Select Burst for Logging Mode in the Launch Logger
window. If Burst has already been configured for this
logger, click the Edit button in the Launch Logger window.
2. In the Burst Logging window, select a sensor from the list. In
the following example, a temperature sensor was selected.
3. Select the High Level checkbox if you want to set up a
condition in which burst logging will occur when the sensor
reading rises above the high level value. Type in the value
or drag the red upper slider.
4. Select the Low Level checkbox if you want to set up a
condition in which burst logging will occur when the sensor
reading falls below the low level value. Type in the value or
drag the blue lower slider.
5. Repeat steps 2 through 4 for any additional sensors.
6. Set the burst logging interval, which must be less than the
logging interval. Select either a preset burst logging interval
or select Custom and enter your own interval. Keep in mind
that the more frequent the burst logging rate, the greater
the impact on battery life and the shorter the logging
duration.
7. Click OK when done. This will return you to the Launch
Logger window. Click the Edit button next to Logging Mode
in the Launch Logger window to make additional changes.
Notes:
 Once the logger is launched, the high and low burst
logging levels are only checked when the logger's
LCD screen refreshes once every 15 seconds. Therefore,
if you set the logging interval to less than 15 seconds and
the sensor reading falls outside the levels, the burst
logging will not begin until the next 15-second refresh
cycle.
 If high and/or low levels have been configured for more
than one sensor, then burst logging will begin when any
high or low condition goes out of range. Burst logging will
not end until all conditions on all sensors are back within
normal range.
 The actual values for burst logging levels are set to the
closest values supported by the logger based on the
sensor type.
 Once the high or low condition clears, the logging
interval time will be calculated using the last recorded
data point in burst logging mode, not the last data point
recorded in “normal mode.” For example, let’s assume
the logger has a 10-minute logging interval and logged a
data point at 9:05. Then, the high level was surpassed
and burst logging began at 9:06. Burst logging then
continued until 9:12 when the sensor reading fell back
below the high level. Now back in normal mode, the next
logging interval will be 10 minutes from the last burst
logging point, or 9:22 in this case. If burst logging had not
occurred, the next data point would have been at 9:15.
 A New Interval event will appear on the plot (if you select
events for plotting in the Plot Setup window) each time
the logger enters or exits burst logging mode.
Statistics
Statistics is a logging mode in which the logger calculates
maximum, minimum, average, and standard deviation statistics
during logging, recording the results at each logging interval
based on samples taken at a rate you specify. This will result in
up to four additional series per sensor that record the following
information at each logging interval:
 The maximum, or highest, sampled value,
 The minimum, or lowest, sampled value,
 An average of all sampled values, and
 The standard deviation from the average for all sampled
values.
For example, let’s say the logging interval is set to 5 minutes
and the sampling interval is set to 30 seconds (with maximum,
minimum, average, and standard deviation all enabled). Once
logging begins, the logger will measure and record the actual
sensor values every 5 minutes. In addition, the logger will take
a sample every 30 seconds and temporarily store it in memory.
The logger will then calculate the maximum, minimum,
average, and standard deviation using the samples gathered
over the previous 5-minute period and log the resulting
value(s). When reading out the logger, this would result in 5
data series for each channel: one sensor series (with data
logged every 5 minutes) plus four maximum, minimum,

HOBO 4-Channel Analog Data Logger (UX120-006M) Manual
average, and standard deviation series (with values calculated
and logged every 5 minutes based on the 30-second sampling).
To set up statistics:
1. Select Statistics for Logging Mode in the Launch Logger
window. If Statistics has already been configured for this
logger, click the Edit button in the Launch Logger window.
2. Click the Maximum, Minimum, Average, and Standard
Deviation checkboxes for each of the statistics you want to
calculate during logging. Note that Average is automatically
enabled when selecting Standard Deviation. In addition, the
more statistics you record, the shorter the logger duration
and the more memory is required.
3. Set the sampling interval, which must be less than and a
factor of the logging interval. Choose either a preset
sampling interval or select Custom and enter your own
sampling interval. Keep in mind that the more frequent the
sampling rate, the greater the impact on battery life.
4. Click OK when done. This will return you to the Launch
Logger window. Click the Edit button next to Logging Mode
in the Launch Logger window to make additional changes.
Once logging begins, click the Alarm/Stats button on the logger
to cycle through the current maximum, minimum, average, and
standard deviation data on the LCD screen. You can plot the
statistics series once you read out the logger.
Reading Out the Logger
There are two options for reading out the logger: connect it to
the computer with a USB cable and read out it with HOBOware,
or connect it to a HOBO U-Shuttle (U-DT-1, firmware version
1.20m030 or higher) and then offload the data files from the
U-Shuttle to HOBOware. Refer to the HOBOware Help for details.
Recording Internal Logger Events
The logger records the following internal events to track logger
operation and status. You can plot these events in HOBOware
after reading out the logger and opening the data file.
Internal Event Name Definition
Host Connected The logger was connected to the computer.
Started The Start/Stop button was pressed to begin
logging.
Stopped The logger received a command to stop
recording data (from HOBOware or by
pushing the Start/Stop button).
Button Up/Button
Down
The Start/Stop button was pressed for
1 second.
Internal Event Name Definition
Chan <#> Alarm
Tripped
An alarm has tripped on that channel.
Chan <#> Alarm
Cleared
An alarm has cleared on that channel. This
event also contains the value that was
furthest out of range for the sensor before
the alarm cleared.
New Interval The logger has entered or exited burst
logging mode.
Safe Shutdown The battery level dropped below 1.85 V; the
logger performs a safe shutdown.
Mounting the Logger
There are several ways to mount the logger using the materials
included:
 Use the four built-in magnets on the back of the logger to
mount it to a magnetic surface.
 Attach the Command strip to the back of the logger to
mount it a wall or other flat surface.
 Use the double-sided tape to affix the logger to a surface.
 Insert the hook-and-loop strap through the mounting
loops on both sides of the logger to mount it to a curved
surface, such as a pipe or tubing.
Protecting the Logger
The logger is designed for indoor use and can be permanently
damaged by corrosion if it gets wet. Protect it from
condensation. If the message FAIL CLK appears on the LCD
screen, there was a failure with the internal logger clock
possibly due to condensation. Remove the batteries
immediately and dry the circuit board.
Note: Static electricity may cause the logger to stop logging.
The logger has been tested to 8 KV, but avoid electrostatic
discharge by grounding yourself to protect the logger. For more
information, search for “static discharge” in the FAQ section on
onsetcomp.com.
Battery Information
The logger requires two user-replaceable AAA 1.5 V alkaline or
optional lithium batteries for operation at the extreme ends of
the logger operating range. Expected battery life varies based
on the ambient temperature where the logger is deployed, the
logging or sampling interval, frequency of offloading to the
computer, number of channels that are active, if burst or
statistics logging modes are active, and battery performance.
New batteries typically last 1 year with logging intervals greater
than 1 minute. Deployments in extremely cold or hot
temperatures, a logging interval faster than 1 minute, or a
sampling interval faster than 15 seconds can impact battery
life. Estimates are not guaranteed due to uncertainties in initial
battery conditions and operating environment.
The logger can also be powered by the USB cable when the
remaining battery voltage is too low for it to continue logging.
Connect the logger to the computer, click the Readout button
on the toolbar, and save the data as prompted. Replace the
battery before launching the logger again.

HOBO 4-Channel Analog Data Logger (UX120-006M) Manual
1-800-LOGGERS (564-4377) • 508-759-9500
www.onsetcomp.com • [email protected]
© 2013 Onset Computer Corporation. All rights reserved. Onset, HOBO, and HOBOware are
trademarks or registered trademarks of Onset Computer Corporation. All other trademarks are the
property of their respective companies.
17384-A
To install or replace the batteries:
1. Open the battery door on the back of the logger.
2. Remove any old batteries.
3. Insert two new batteries observing polarity.
4. Reinsert the battery door and snap it back into place.
WARNING: If using optional lithium batteries, do not cut
open, incinerate, heat above 85°C (185°F), or recharge the
lithium batteries. The batteries may explode if the logger is
exposed to extreme heat or conditions that could damage or
destroy the batteries case. Do not dispose of the logger or
batteries in fire. Do not expose the contents of the batteries to
water. Dispose of the batteries according to local regulations
for lithium batteries.
HOBOware provides the option of recording the current battery
voltage at each logging interval, which is disabled by default.
Recording battery life at each logging interval takes up memory
and therefore reduces logging duration. It is recommended you
only record battery voltage for diagnostic purposes.
Battery door
Mounting
magnet
Mounting
magnets