PNI SeaTRAX - Manual (Page 13)

PNI Sensor Corporation DOC#1018154 r02
SeaTRAX User Manual Page 8
4.2.1 Operate within the SeaTRAX
’s dynamic range
The SeaTRAX can be user calibrated to correct for static magnetic fields created by the
host system. However, each axis of the SeaTRAX has a calibrated dynamic range of
±125 µT. If the total field exceeds this value for any axis, the SeaTRAX may not
perform to specification. When mounting the SeaTRAX, consider the effect of any
sources of magnetic fields in the host environment that, when added to Earth’s field, may
take the SeaTRAX out of its dynamic regime. For example, large masses of ferrous
metals such as transformers and vehicle chassis, large electric currents, permanent
magnets such as electric motors, and so on.
4.2.2 Locate away from changing magnetic fields
It is not possible to calibrate for changing magnetic anomalies. Thus, for greatest
accuracy, keep the SeaTRAX away from sources of local magnetic distortion that will
change with time; such as electrical equipment that will be turned on and off, or ferrous
bodies that will move. Make sure the SeaTRAX is not mounted close to cargo or payload
areas that may be loaded with large sources of local magnetic fields.
4.2.3 Mount in a physically stable location
Choose a location that is isolated from excessive shock, oscillation, and vibration. The
SeaTRAX works best when stationary. Any non-gravitational acceleration results in a
distorted reading of Earth’s gravitational vector, which affects the heading measurement.
4.2.4 Location-verification testing
Location-verification testing should be performed at an early stage of development to
understand and accommodate the magnetic distortion contributors in a host system.
Determine the distance range of field distortion.
Place the heading sensor in a fixed position, then move or energize suspect
components while observing the output to determine when they are an influence.
Determine if the magnetic field is within the dynamic range of the heading
sensor.
With the heading sensor mounted, rotate and tilt the system in as many positions as
possible. While doing so, monitor the magnetometer outputs, observing if the
maximum linear range is exceeded.