PNI TCM - Manual (Page 14)

PNI Sensor Corporation DOC#1014688 r06
TCM User Manual – July 2013 Page 9
4.2 Installation Location
The TCM’s wide dynamic range and sophisticated calibration algorithms allow it to operate
in many environments. For optimal performance however, you should mount the TCM with
the following considerations in mind:
4.2.1 Operate within
the TCM’s dynamic range
The TCM can be user calibrated to correct for static magnetic fields created by the host
system. However, each axis of the TCM has a calibrated dynamic range of ±125 µT. If
the total field exceeds this value for any axis, the TCM may not perform to specification.
When mounting the TCM, consider the effect of any sources of magnetic fields in the
host environment that, when added to Earth’s field, may take the TCM 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 TCM 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 TCM 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
TCM 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 compass in a fixed position, then move or energize suspect components
while observing the output to determine when they are an influence.