Hardware
Heat considerations
Digi XBee Cellular LTE Cat 1 Embedded Modem User Guide
35
LED status
Blink
timing
Meaning
Double blink
½ second The last TCP/UDP/SMS attempt failed. If the LED has this pattern,
you may need to check
or
(Protocol/Connection Indication)
for the cause of the error.
Standard single blink 1 second Normal operation.
The normal association LED signal alternates evenly between high and low as shown below:
Where the low signal means LED off and the high signal means LED on.
When
CI
is not
0
or
0xFF
, the Associate LED has a different blink pattern that looks like this:
Heat considerations
Depending on the use case, your application may require a heat sink. Use a non-conductive thermal
gasket to make contact to the heat sink. The gasket should be thick enough to ensure that contact
with the tallest component does not cause damage when pressure is applied to a secure heat sink.
We recommend connecting the heat sink to the top side of the XBee Cellular Modem without covering
the U.FL connectors.
We do not recommend operating the unit above 80 °C.
The operation temperature of the unit can be approximated for different current draws and extreme
cases by the equation below. For best results, attach a temperature probe just above the center of
the XBee Cellular Modem. Alternatively use
to query the current temperature of the
device's processor.
Where
1.
XBeeBoardTemp
is the temperature of the XBee Cellular Modem at steady state.
a. Use the
TP
command to help estimate the temperature when attaching a
temperature probe is not practical, but for reliable results, you must use a
temperature probe.
2.
RoomTemp
is the temperature of the ambient air.
3.
AverageCurrentDuringTest
is the average current measured during test.
4.
ScenarioMaxCurrent
is the maximum current expected for the device.
Heat sink considerations
The following table provides a set of typical heat sink examples for scenarios that customers may
encounter.