Hobo Pendant MX Temp User manual

HOBO® Pendant® MX Temp (MX2201) and
Temp/Light (MX2202) Logger Manual
21536-L
HOBO Pendant MX loggers measure temperature (MX2201) or temperature/light (MX2202) in
indoor and outdoor environments. Designed for durability, these compact, waterproof loggers
can be used in numerous applications, including fresh and salt water. The loggers are
Bluetooth® Low Energy-enabled for wireless communication with a mobile device. Using the
HOBOconnect™ app, you can easily configure the loggers, download logged data to your phone
or tablet, or automatically upload the data to HOBOlink® for further analysis. You can also
configure the loggers to calculate statistics, set up alarms to trip at specific thresholds, or
enable burst logging in which data is logged at a faster interval when sensor readings are above
or below certain limits.
Specifications
Temperature Sensor (MX2201 and MX2202)
Range -20° to 70°C (-4° to 158°F) in air
-20° to 50°C (-4° to 122°F) in water
Accuracy ±0.5°C from -20° to 70°C (-4° to 158°F)
Resolution 0.04°C (0.072°F)
Drift <0.1°C (0.18°F) per year
Response Time 17 minutes typical to 90% in air moving 1 m/s, unmounted
7 minutes typical to 90% in stirred water, unmounted
Light Sensor (MX2202)
Range 0 to 167,731 lux (15,582 lum/ft
2
)
Accuracy ±10% typical for direct sunlight (see Light Measurement on page 2 for
more details)
Logger
Logger Operating Range -20° to 70°C (-4° to 158°F) in air
Buoyancy (Fresh Water) 2 g (0.07 oz) positive
Waterproof To 30.5 m (100 ft)
Radio Power 1 mW (0 dBm)
Transmission Range Approximately 30.5 m (100 ft) line-of-sight
Wireless Data Standard Bluetooth Low Energy (Bluetooth Smart)
Logging Rate 1 second to 18 hours
Time Accuracy ±1 minute per month at 25°C (77°F)
Battery CR2032 3V lithium, user replaceable
Battery Life 1 year typical at 25°C (77°F) with logging interval of 1 minute and
Bluetooth Always On enabled in software.
2 years typical at 25°C (77°F) with logging interval of 1 minute and
Bluetooth Always On disabled in software.
Faster logging intervals and statistics sampling intervals, burst logging,
remaining connected with the app, excessive downloads, and paging
may impact battery life.
To ensure proper battery installation, see Battery Information for
detailed instructions on replacing the battery.
Memory 96,000 measurements
Full Memory Download
Time
Approximately 45 seconds; may take longer the farther the device is
from the logger
Wetted Materials Polypropylene case, EPDM O-ring
Dimensions 3.35 x 5.64 x 1.8 cm (1.32 x 2.22 x 0.69 inches)
W
eight 12.75 g (0.45 oz)
Environmental Rating IP68
The CE Marking identifies this product as complying with all relevant
directives in the European Union (EU).
See last page
HOBO Pendant MX
Logger
Models:
•MX Temp (MX2201)
•MX Temp/Light
(MX2202)
Required Items:
•HOBOconnect app
•Mobile device with
Bluetooth and iOS,
iPadOS®, or Android™
Accessories:
•Mounting boot 5-pack
(BOOT-MX2201-2202)
•Solar radiation shield
(RS1 or M-RSA)
•Mounting bracket for
solar radiation shield
(MX2200-RS-BRACKET)
•Replacement O-rings
(MX2201-02-ORING)
MX2201 Model Shown

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Logger Components and Operation
MX2202 model shown
Mounting Tab: Use the tabs at the top and bottom of the
logger to mount it (see Deploying and Mounting the Logger).
Temperature and Light Sensors: The temperature sensor
(MX2201 and MX2202) and light sensor (MX2202) are located
on the right side of the logger. See Light Measurement for more
details on the light sensor.
Status LED: This LED blinks green every 4 seconds when the
logger is logging (unless Show LED is disabled as described in
Configuring the Logger). If the logger is waiting to start logging
because it was configured to start “On Button Push” or with a
delayed start, it will blink green every 8 seconds. Both this LED
and the Alarm LED will blink once when you press the start
button to wake up the logger before configuring it. If you select
in the app, both LEDs will be illuminated for 5 seconds (see
Getting Started for more details).
Alarm LED: This LED blinks red every 4 seconds when an alarm
is tripped (unless Show LED is disabled as described in
Configuring the Logger).
Start Button: Press the circle on the front of the logger case for
1 second to wake up the logger (unless Bluetooth Always On is
enabled as described in Configuring the Logger). Both LEDs will
blink and the logger will move to the top of the devices list in
the app. You may need to press the button a second time to
wake up the logger if it is logging every 5 seconds or faster and
the temperature is -10°C (14°F) or below. Press this circle for 3
seconds to start or stop the logger when it is configured to start
or stop “On Button Push” (see Configuring the Logger). Both
LEDs will blink four times when you press the circle to start or
stop logging. Press this circle for 10 seconds to reset a
password. Note: The circle on the front of the logger represents
the button area on the logger. You will not feel an actual button
push when you press that area; this is normal.
Light Measurement (MX2202)
The logger measures light intensity in units of lumens/ft
2
or lux.
The light sensor in the MX2202 has a spectral response that
tightly matches the photopic response of the human eye. This is
shown in Plot A.
The light sensor has range of 0 to 167,731 lux (15,582 lum/ft
2
).
The resolution of the light measurement varies from 1 unit of
lux or lum/ft
2
in very dim light to 40 lux (4 lum/ft
2
) for a full
scale measurement.
Plot A
Light Measurement Accuracy
Although the MX2202 is factory calibrated to account for the
light attenuation of the plastic enclosure, you may notice a
significant difference in the MX2202 reading compared to a
commercially available lux meter. Ideally, a light meter’s
response should be proportional to the cosine of the angle at
which the light is incident. The MX2202 does not collect light
exactly according to this rule. Plot B illustrates the difference
between an ideal cosine response and the approximate
response of the MX2202. For example, given an incident angle
of 60°, the MX2202 response is 40% lower than the ideal
response. The MX2202 is calibrated to give best results for
direct illumination, but this is not always the case.
Plot B
Getting Started
Install the app to connect to and work with the logger.
1. Download HOBOconnect from the App Store® or Google
Play™.
2. Open the app and enable Bluetooth in the device settings if
prompted.
3. Firmly press the circular button near the center of the
logger to wake it up. Both LEDs on the logger will blink once
when it wakes up.
4. Tap Devices and then tap the logger in the app to connect
to it.
If the logger does not appear or if it is having trouble
connecting, follow these tips.
•Make sure the logger is “awake” by pressing the circle on
the case. The alarm and status LEDs will blink once when
Alarm LED
Status LED
Temperature and
Light Sensors
Mounting
Tab
Start
Button

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the logger wakes up. This will also bring the logger to the
top of the list if you are working with multiple loggers.
•If the logger is currently logging at a fast interval (5
seconds or faster) and the temperature is -10°C (14°F) or
below, you may need to press the button twice before it
appears in the list.
•Make sure the logger is within range of your mobile
device. The range for successful wireless communication
in air is approximately 30.5 m (100 ft) with full line-of-
sight.
•Change the orientation of your phone or tablet to ensure
the antenna in your device is pointed toward the logger.
Obstacles between the antenna in the device and the
logger may result in intermittent connections.
•If your device can connect to the logger intermittently or
loses its connection, move closer to the logger, within
sight if possible. If the logger is in water, the connection
can be unreliable. Remove it from water for a consistent
connection.
•If the logger appears in the app, but you cannot connect
to it, close the app and power cycle the mobile device.
This forces the previous Bluetooth connection to close.
Once the logger is connected, you can:
Tap this: To do this:
Select logger settings and save them onto the
logger to start logging. See Configuring the
Logger.
Read out (offload) logger data. See Reading Out
the Logger.
Start logging if the logger was configured to start
with a button push. See Configuring the Logger.
Stop the logger from recording data (this
overrides any Stop Logging settings described in
Configuring the Logger).
Illuminate the logger LEDs for 5 seconds.
Set a password for the logger that will be
required if another mobile device attempts to
connect to it. To reset a password, press the
circle on the logger for 10 seconds or tap and
tap Reset.
Mark the logger as a favorite. You can then filter
the list of devices to only show loggers marked
as favorites.
Update the firmware on the logger. A logger
readout will be completed automatically at the
beginning of the firmware update process
Important: Before updating the firmware on
the logger, check the remaining battery level
and make sure it is no less than 30%. Make
sure you have the time to complete the
entire update process, which requires that
the logger remains connected to the device
during the upgrade.
Configuring the Logger
Use the app to set up the logger, including selecting the logging
interval, start and stop logging options, and configuring alarms.
These steps provide an overview of setting up the logger. For
complete details, see the app user’s guide.
1. Tap Devices and then tap the logger to connect to it. If the
logger was configured with Bluetooth Always On disabled,
firmly press the circle on the logger to wake it up. This will
also bring the logger to the top of the logger list.
2. Tap to configure the logger.
3. Tap Name and type a name for the logger (optional). If no
name is selected, the logger serial number is used as the
name.
4. Tap Group to add the logger to a group (optional). Tap Save.
5. Tap Logging Interval and choose how frequently the logger
will record data unless operating in burst logging mode (see
Burst Logging).
6. Tap Start Logging and select when logging will begin:
•Now. Logging will begin immediately after configuration
settings are loaded on the logger.
•On Next Logging Interval. Logging will begin at the next
even interval as determined by the selected logging
interval.
•On Button Push. Logging will begin once you press the
circle on the logger for 3 seconds.
•On Date/Time. Logging will begin at a date and time you
specify. Select the date and time.
Tap Save.
7. Tap Stop Logging and select the options for when logging
will end.
a. Choose one of two memory options:
•When Memory Fills. The logger will continue recording
data until the memory is full.
•Never (Wrap When Full). The logger will continue
recording data indefinitely, with newest data
overwriting the oldest.
b. Select On Button Push if you want to be able to stop
logging by pushing the circle on the logger for 3 seconds.
c. Select one of the following time options for when to stop
logging:
•Never. Select this if you do not want the logger to stop
at any predetermined time frame.
•On Date/Time. Select this if you want the logger to
stop logging on a specific date and time. Select the
date and time.
•After. Select this if you want to control how long the
logger should continue logging once it starts. Choose
the amount of time you want the logger to log data.
For example, select 30 days if you want the logger to
log data for 30 days after logging begins.
d. Tap Save.
8. Tap Logging Mode. Select either fixed or burst logging. With
fixed logging, the logger records data for all enabled sensors
and/or selected statistics at the logging interval selected
(see Statistics Logging for details on choosing statistics
>
>
>
>
>
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options). In burst mode, logging occurs at a different
interval when a specified condition is met. See Burst
Logging for more information. Tap Save.
9. Enable or disable Show LED. If Show LED is disabled, the
alarm and status LEDs on the logger will not be illuminated
while logging (the alarm LED will not blink if an alarm trips).
You can temporarily turn on LEDs when Show LED is
disabled by pressing the circle on the logger for 1 second.
10. Enable or disable Bluetooth Always On. When this option is
enabled, the logger will “advertise” or regularly send out a
Bluetooth signal for the phone or tablet to find via the app
while it is logging, which uses battery power. When this
option is disabled, the logger will only advertise during
logging when you press the circle on the logger to wake it
up, thereby preserving as much battery power as possible.
11. For the Pendant MX Temp/Light (MX2202) logger, both the
temperature and light sensors are enabled by default.
Disable one if desired.
12. You can set up alarms to trip when a sensor reading rises
above or falls below a specified value. See Setting up Alarms
for details on enabling sensor alarms.
13. Tap to save the configuration settings.
Logging will begin based on the settings you selected. See
Deploying and Mounting the Logger for details on mounting
and see Reading Out the Logger for details on downloading.
Setting up Alarms
You can set up alarms for the logger so that if a sensor reading
rises above or falls below a specified value, the logger alarm
LED will blink and an alarm icon will appear in the app. This can
alert you to problems so you can take corrective action.
To set an alarm:
1. Tap Devices. Press the circle on the logger to wake it up (if
necessary).
2. Tap the logger in the app to connect to it and tap .
3. Tap a sensor (tap the Enable Logging toggle if necessary).
4. Select High if you want an alarm to trip when the sensor
reading rises above the high alarm value. Drag the slider or
type a value to set the high alarm value.
5. Select Low if you want an alarm to trip when the sensor
reading falls below the low alarm value. Drag the slider or
type a value to set the low alarm value.
6. For the Duration, select how much time should elapse
before the alarm trips and select one of the following:
•Cumulative. The alarm will trip once the sensor reading is
out of the acceptable range for the selected duration any
time during logging. For example, if the high alarm is set
to 85°F and the duration is set to 30 minutes, then the
alarm will trip once the sensor readings have been above
85°F for a total of 30 minutes since the logger was
configured.
•Consecutive. The alarm will trip once the sensor reading
is out of the acceptable range continuously for the
selected duration. For example, the high alarm is set to
85°F and the duration is set to 30 minutes, then the
alarm will only trip if all sensor readings are 85°F or
above for a continuous 30-minute period.
7. Tap Save and repeat steps 3–7 for the other sensor if
desired. Note that when both alarms are configured, an
alarm is raised when either sensor is in an alarm condition.
8. In the configuration settings, select one of the following
options to determine how the alarm indications are cleared:
•Logger Reconfigured. The alarm indication will display
until the next time the logger is reconfigured.
•Sensor in Limits. The alarm icon indication will display
until the sensor reading returns to the normal range
between any configured high and low alarm limits.
9. Tap .
When an alarm trips, the logger alarm LED blinks every 4
seconds (unless Show LED is disabled), an alarm icon appears in
the app, and an Alarm Tripped event is logged. The alarm state
will clear when the readings return to normal if you selected
Sensor in Limits in step 8. Otherwise, the alarm state will
remain in place until the logger is reconfigured.
Notes:
•Alarm limits are checked at every logging interval. For
example, if the logging interval is set to 5 minutes, then
the logger will check the sensor readings against your
configured high and low alarm setting every 5 minutes.
•The actual values for the high and low alarm limits are set
to the closest value supported by the logger. In addition,
alarms can trip or clear when the sensor reading is within
the resolution specifications.
•When you read out the logger, alarm events can be
displayed on the plot or in the data file. See Logger
Events.
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, a logger is recording data at a 5-minute logging
interval and burst logging is configured to log every 30 seconds
when the temperature rises above 85°F (the high limit) or falls
below 32°F (the low limit). 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 rises above
85°F, the logger will switch to the faster logging rate and record
data every 30 seconds until the temperature falls back to 85°F.
At that time, logging then resumes every 5 minutes at the
normal logging interval. Similarly, if the temperature falls below
32°F, then the logger would switch to burst logging mode again
and record data every 30 seconds. Once the temperature rises
back to 32°F, the logger will then return to normal mode,
logging every 5 minutes. Note: Sensor alarms, statistics, and the
Stop Logging option “Wrap When Full” are not available in
burst logging mode.
To set up burst logging:
1. Tap Devices. Press the circle on the logger to wake it up (if
necessary).
2. Tap the logger in the app to connect to it and tap .
3. Tap Logging Mode and then tap Burst Logging.
4. Select Low and/or High and either type or drag the slider to
set the low and/or high values.

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5. Repeat step 4 for the other sensor if desired.
6. Set the burst logging interval, which must be faster than the
logging interval. Keep in mind that the faster the burst
logging rate, the greater the impact on battery life and the
shorter the logging duration. Because measurements are
being taken at the burst logging interval throughout the
deployment, the battery usage is similar to what it would be
if you had selected this rate for the normal logging interval.
7. Tap Save.
8. Tap .
Notes:
•The high and low burst limits are checked at the burst
logging interval rate whether the logger is in normal or
burst condition. For example, if the logging interval is set
to 1 hour and the burst logging interval is set to 10
minutes, the logger will always check for burst limits
every 10 minutes.
•If high and/or low limits 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 the burst logging limits are set to
the closest value supported by the logger. In addition,
burst logging can begin or end when the sensor reading is
within the specified resolution. This means the value that
triggers burst logging may differ slightly than the value
entered.
•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 at the normal logging rate. For example, the
logger has a 10-minute logging interval and logged a data
point at 9:05. Then, the high limit 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 limit. 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 is created each time the logger
enters or exits burst logging mode. See Logger Events for
details on plotting and viewing the event. In addition, if
the logger is stopped with a button push while in burst
logging mode, then a New Interval event is automatically
logged and the burst condition is cleared, even if the
actual high or low condition has not cleared.
Statistics Logging
During fixed logging, the logger records data for enabled
sensors and/or selected statistics at the logging interval
selected. Statistics are calculated at a sampling rate you specify
with the results for the sampling period recorded at each
logging interval. The following statistics can be logged for each
sensor:
•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, a Pendant MX Temp/Light (MX2202) logger is
configured with both the temperature and light sensors
enabled, and the logging interval set to 5 minutes. The logging
mode is set to fixed interval logging with Normal and all four
statistics enabled and with a statistics sampling interval of 30
seconds. Once logging begins, the logger will measure and
record the actual temperature and light values every 5 minutes.
In addition, the logger will take a temperature and light sample
every 30 seconds and temporarily store them 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 values. When
reading out the logger, this would result in 10 data series: two
sensor series (with temperature and light data logged every 5
minutes) plus eight maximum, minimum, average, and standard
deviation series (four for temperature and four for light with
values calculated and logged every 5 minutes based on the 30-
second sampling).
To log statistics:
1. Tap Devices. Press the circle on the logger to wake it up (if
necessary).
2. Tap the logger in the app to connect to it and tap .
3. Tap Logging Mode and then select Fixed Logging.
4. Select Normal to record the current reading for each
enabled sensor at the logging interval shown at the top of
the screen. Do not select this if you only want to log
statistics.
5. Select the statistics you want the logger to record at each
logging interval: Maximum, Minimum, Average, and
Standard Deviation (average is automatically enabled when
selecting Standard Deviation). Statistics will be logged for all
enabled sensors. In addition, the more statistics you record,
the shorter the logger duration and the more memory is
required.
6. Tap Statistics Sampling Interval and select the rate to use
for calculating statistics. The rate must be less than, and a
factor of, the logging interval. For example, if the logging
interval is 1 minute and you select 5 seconds for the
sampling rate, then the logger will take 12 sample readings
between each logging interval (one sample every 5 seconds
for a minute) and use the 12 samples to record the resulting
statistics at each 1-minute logging interval. Note that the
faster the sampling rate, the greater the impact on battery
life. Because measurements are being taken at the statistics
sampling interval throughout the deployment, the battery
usage is similar to what it would be if you had selected this
rate for the normal logging interval.
7. Tap Save.
8. Tap .
Setting a Password
You can create an encrypted password for the logger that will
be required if another phone or tablet attempts to connect to
it. This is recommended to ensure that a deployed logger is not
mistakenly stopped or purposely altered by others. This

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password uses a proprietary encryption algorithm that changes
with every connection.
To set a password:
1. Tap Devices. Press the circle on the logger to wake it up (if
necessary). Tap the logger in the app to connect to it.
2. Tap and then .
3. Type a password and then tap Set.
Only the phone or tablet used to set the password can then
connect to the logger without entering a password; all other
mobile devices will be required to enter the password. For
example, if you set the password for the logger with your tablet
and then try to connect to the device later with your phone,
you will be required to enter the password on the phone but
not with your tablet. Similarly, if others attempt to connect to
the logger with different devices, then they would also be
required to enter the password. To reset a password, press the
circle on the logger for 10 seconds or connect to the logger and
tap , then , and tap Reset.
Reading Out the Logger
To download data from the logger:
1. Tap Devices. Press the circle on the logger to wake it up (if
necessary). Tap the logger in the app to connect to it.
2. Tap the logger in the app to connect to it and tap . The
logger will read out the data to the phone or tablet.
3. Once the readout is complete, tap HOBO Files and select
the file to view it. Tap and then to export and share
the data.
Data can also be uploaded automatically to HOBOlink, Onset’s
web-based software, via the app or the MX gateway. For
details, see the app user’s guide and see the HOBOlink help for
details on working with data in HOBOlink.
Logger Events
The logger records the following events to track logger
operation and status. You can view events in exported files or
plot events in the app.
To plot events, tap HOBO Files and select a file to open.
Tap and then tap . Select the events you want to plot
and tap OK.
Event Name Definition
Host Connect The logger was connected to a mobile
device.
Started The logger started logging.
Stopped The logger stopped logging.
Chan <#> Alarm
Tripped/Cleared
An alarm has occurred because the
reading was outside the alarm limits or
back within range. Note: Although the
reading may return to a normal range, an
alarm cleared event will not be logged if
the logger was set up to maintain alarms
until reconfigured.
Event Name Definition
Button Up/Down The
circle on the logger was pressed to
wake it up/bring it to the top of the
loggers list in the app.
New Interval The logger has switched to logging at the
burst logging rate or back to the normal
rate.
Power Warn The battery level dropped below 2.3 V.
Safe Shutdown The battery level dropped below a safe
operating voltage and performed a safe
shutdown.
Deploying and Mounting the Logger
When mounting the logger, it is very important that the logger
housing does not get distorted. If you are mounting the logger
on an irregular surface, it is recommended that you use the
mounting boot (BOOT-MX2201-2202).
•The logger must be mounted to a flat surface or in a way
that prevents the logger housing from bowing. You can
deploy the logger by using the two mounting tabs. Insert
two screws through the round holes on the mounting
tabs to affix the logger to a flat surface, being careful not
to overtighten the screws. Alternatively, you can hang
the logger using a loose zip tie loop.
Guidelines for Using the Mounting Boot
•To install the logger in a boot, hold both the boot and the
logger upside down and insert the logger mounting tab
into the boot as shown.
Insert the other logger mounting tab into the boot,
making sure the logger is securely seated in the boot as
shown.
Use screws with
the round holes

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•To mount the logger in a boot to a small pipe, use two of
the zip ties included with the boot as shown.
•To mount the logger in a boot to a large pipe, use one of
the zip ties included with the boot as shown.
•To mount the logger in a boot to a flat surface, use two
#8 screws as shown. Do not overtighten the screws.
Other Deployment Guidelines
•When deploying in water, the logger should be
appropriately weighted, secured, and protected
depending on water conditions and desired
measurement location.
•Loggers deployed in direct sunlight will heat up so that
temperature readings are warmer than the ambient
temperature. Use a solar radiation shield to ensure
temperature readings represent the ambient
temperature.
Attach the logger to a solar radiation shield (RS1 or M-
RSA) using the solar radiation shield bracket (MX2200-RS-
BRACKET). Attach the logger to the underside of the
mounting plate as shown in the following example. For
more details on the solar radiation shield, refer to the
Solar Radiation Shield Installation Guide at
www.onsetcomp.com/manuals/rs1. Note: To log both
temperature and sunlight, you will need two MX2202
loggers. Place one logger in a solar radiation shield to log
temperature and the other mounted flat on top of the
solar radiation shield to record sunlight.
•When measuring light intensity outdoors or underwater,
make sure the MX2202 logger is mounted horizontally so
that the light sensor is pointing straight up towards the
sky as shown in this example.
•Be careful of solvents. Check a materials compatibility
chart against the wetted materials listed in the
Specifications table before deploying the logger in
locations where untested solvents are present. The
logger has an EPDM O-ring, which is sensitive to polar
solvents (acetone, keton) and oils.
Maintaining the Logger
•To clean the logger, rinse it in warm water. Use a mild
dishwashing detergent if necessary. Do not use harsh
chemicals, solvents, or abrasives.
•Periodically inspect the logger for biofouling if it is
deployed in water and clean as described.
•Periodically inspect the O-ring on the inside of the
battery cover for cracks or tears and replace it if any are
detected (MX2201-02-ORING). See Battery Information
for steps on replacing the O-ring.
Protecting the Logger
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” on
www.onsetcomp.com.
Battery Information
The logger requires one user-replaceable CR2032 3V lithium
battery. Battery life is 1 year typical at 25°C (77°F) with a
logging interval of 1 minute and Bluetooth Always On enabled
or 2 years typical at 25°C (77°F) when the logger is configured
with Bluetooth Always On disabled. Expected battery life varies
based on the ambient temperature where the logger is
deployed, the logging interval, the frequency of connections,
downloads, and paging, and the use of burst mode or statistics

HOBO Pendant MX Temp (MX2201) and Temp/Light (MX2202) Logger Manual
1-800-LOGGERS 8 www.onsetcomp.com
logging. Deployments in extremely cold or hot temperatures or
a logging interval faster than one minute can impact battery
life. Estimates are not guaranteed due to uncertainties in initial
battery conditions and operating environment.
To replace the battery:
1. While pushing down with both thumbs on the back of the
logger, rotate the battery cover counterclockwise until it
stops moving (about a 1/8 turn).
2. Use the edge below the arrow on the cover to lift it off the
logger.
3. Remove the battery and place a new one in the battery
holder, positive side facing up. Use a small flat-head
screwdriver to carefully pop the battery out of its holder as
shown.
4. Inspect the O-ring on the battery cover. Make sure it is
clean and seated properly. Remove any dirt, lint, hair, or
debris from the O-ring. If the O-ring has any cracks or tears,
replace it as follows:
a. Spread a small dot of silicone-based grease on the O-
ring with your fingers, making sure the entire O-ring
surface is completely covered in grease.
b. Place the O-ring on the cover and clean off any debris.
Make sure the O-ring is fully seated and level in the
groove and not pinched or twisted. This is necessary to
maintain a waterproof seal.
5. Place the cover back on the logger as shown, aligning the
notches in the cover with the rounded tabs on the logger
case. The cover will not close properly and maintain a
waterproof seal if it is misaligned.
6. While pushing down with both thumbs, rotate the battery
cover clockwise until it locks in position under the two large
corner tabs and the two small rounded tabs.
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.
Use this edge to
lift the cover off
Align notch in cover with
small, rounded tab on logger
Cover secured under
rounded tab
Cover secured
under corner tab
Cover secured
under corner tab
Cover secured under
rounded tab
Align notch in cover with
small, rounded tab on logger

HOBO Pendant MX Temp (MX2201) and Temp/Light (MX2202) Logger Manual
1-800-LOGGERS (564-4377) • 508-759-9500
www.onsetcomp.com/support/contact
© 2017–2020 Onset Computer Corporation. All rights reserved. Onset, HOBO, Pendant, HOBOconnect, and
HOBOlink are trademarks or registered trademarks of Onset Computer Corporation. App Store and iPadOS are
service marks or registered trademarks of Apple Inc. Android and Google Play are trademarks of Google LLC.
Bluetooth and Bluetooth Smart is a registered trademark of Bluetooth SIG, Inc. All other trademarks are the
property of their respective companies.
Patent #: 8,860,569 21536-L
Federal Communication Commission Interference Statement
This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide
reasonable protection against harmful interference in a residential installation. This equipment generates uses and can radiate radio frequency energy and, if not installed and
used in accordance with the instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a
particular installation. If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user
is encouraged to try to correct the interference by one of the following measures:
•Reorient or relocate the receiving antenna
•Increase the separation between the equipment and receiver
•Connect the equipment into an outlet on a circuit different from that to which the receiver is connected
•Consult the dealer or an experienced radio/TV technician for help
This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) This device may not cause harmful interference, and (2) this device
must accept any interference received, including interference that may cause undesired operation.
FCC Caution: Any changes or modifications not expressly approved by the party responsible for compliance could void the user's authority to operate this equipment.
Industry Canada Statements
This device complies with Industry Canada license-exempt RSS standard(s). Operation is subject to the following two conditions: (1) this device may not cause interference, and
(2) this device must accept any interference, including interference that may cause undesired operation of the device.
Avis de conformité pour l’Industrie Canada
Le présent appareil est conforme aux CNR d'Industrie Canada applicables aux appareils radio exempts de licence. L'exploitation est autorisée aux deux conditions suivantes : (1)
l'appareil ne doit pas produire de brouillage, et (2) l'appareil doit accepter tout brouillage radioélectrique subi, même si le brouillage est susceptible d'en compromettre le
fonctionnement.
To comply with FCC and Industry Canada RF radiation exposure limits for general population, the logger must be installed to provide a separation distance of at least 20cm from
all persons and must not be co-located or operating in conjunction with any other antenna or transmitter.
KC Statement
해당 무선설비는 전파혼신 가능성이 있으므로 인명안전과 관련된 서비스는 할 수 없음
Translation:
The service related to human safety is not allowed because this device may have the possibility of the radio interference.