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3.3.6
Power saving
In power-saving mode, sensors will turn off the signal pipeline and BLE connection, put the
MCU in a sleep state to ensure minimum power consumption. In this state, sensors cannot
be discovered by host devices.
The default time thresholds to enter power saving mode is set to 10 min in advertisement
mode and 30 min in connection mode. Power saving mode can be disabled and the time
thresholds can be adjusted in Xsens DOT App, SDK or by BLE services.
Sensors will exit power saving mode when:
•
Power button is pressed
•
Acceleration is detected by accelerometer
Once the sensor enters power saving mode, you can wake it up by pressing the power
button
or
simply shaking it. Xsens DOT will return to advertisement mode when exiting
power saving mode.
3.4
Magnetic Field Mapper
When Xsens DOT sensor is mounted to an object that contains ferromagnetic materials,
the measured magnetic field can become distorted, causing errors in measured orientation.
To correct for known magnetic disturbances, Magnetic Field Mapper function has been
developed to allow users to remap the magnetic field of the sensor.
The MFM can be executed in a few minutes and yields a new set of calibration values that
can be written to the Xsens
DOT’s non
-volatile memory, which means it will not be erased
by powering off or firmware updates.
You can perform MFM with 5 sensors at the same time. Follow these steps to do the MFM
for Xsens DOT. Here is a detailed
about how to do MFM in the App.
1.
Open Xsens DOT App (Android or iOS)
2.
Connect the target sensors
3.
Go to
Advanced
→
Magnetic Field Mapper
4.
Select sensors to start MFM
5.
Rotate the sensors slowly around all three axes and in all directions to collect data
for magnetic field calibration. The process automatically checks for data points that
are relevant and give sufficient coverage for a proper MFM procedure. The progress
bar indicates this and once the bar reaches 100%, MFM process will begin
automatically.
6.
MFM is successful when showing “Finished”. Restart the MFM if it fails.
A .mtb file containing the calibration data will be created during the MFM. You can find it
in your mobile phone:
•
Android: under this directory
Android/data/com.xsens.dot.android/files/mfm
•
iOS: Goto Files App
→
On My iPhone
→
Xsens DOT
→
mfm
NOTES:
•
Stop the synchronization and set output rate to 60Hz before starting MFM.
