Lowell MAT-1 Data Logger, Руководство пользователя

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Universal User Guide, Rev L, February 2022 46
8 Sensor Information
The accelerometer and magnetometer sensors are solid-state integrated circuits designed for use in
consumer products such as cellular phones, game controllers, and personal navigation systems. The
temperature sensor is a precision thermistor. Detailed information on sensor performance can be found
in the relevant
Product Data Sheets .
8.1 Sensor Orientation
The accelerometer and magnetometer are oriented such that the X, Y and Z axes follow the right hand-
rule. The accelerometer produces positive values on an axis when the axis pointed down towards the
center of the earth. The
magnetometer produces positive
values on an axis when the axis is
aligned towards a magnetic north
pole.
•
The Z axis is parallel to the length
of the case, with the positive
direction towards the removable
end cap and USB connector.
•
The X axis is perpendicular to the
circuit board with the positive
direction upwards from the
microSD socket.
•
The Y axis is in the plane of the
circuit board with the positive
axis to the left of the USB connector as viewed looking into the logger with the USB connector and
LEDs facing down.
8.2 Magnetometer
The magnetometer is a temperature compensated three-axis integrated circuit. The sensor measures
absolute magnetic field strength. The magnetometer
’ s data can be used to determine the compass
bearing with respect to the logger’ s orientation or to determine magnetic field strength and orientation.
The logger circuit board and housing were designed to use the absolute minimum of ferrous
components so as to minimize hard and soft iron effects.
The magnetometer’s response can be shifted if the sensor is subject to magnetic fields of greater than
~100 Gauss. Keep powerful “rare earth” mag nets far away from the logger as they can induce a semi-
permanent offset of several hundred mG. Loggers that have been subjected to a strong magnetic field
will need to be recalibrated and/or degaussed (contact Lowell Instruments).
X
Y
Z