18
Application Note 5. Finding the Centre of a Target
The sensors in the M-Scan are orientated along the axis of the
tube. When the tube is placed at right-angles to a magnetic field
(
Figure 7
A
) no field will be detected. When the magnetic lines of
flux are parallel to the tube (
Figure 7
B
) the strongest response
will be obtained. When the M-Scan is held at an angle
to the ground the point of maximum reading may not
be directly over the object.
This also has relevance in mid-latitude regions of the world,
where the Earth’s field dips down at an angle, and buried objects
may produce a field which is at an angle relative to the sensor
tube, even if the tube is held vertically.
The signal peak will be detetced off centre where the lines
of flux are parallel to the sensor tube (
Figure 7
B
). It is important
to traverse objects from right to left and left to right so that
a picture of what is below the ground surface can be visualised
and the centre of the target determined.
Figure 7
No magnetic field will be detected
when the lines of magnetic flux
are at right-angles to the sensor tube
(
A
)
.
When the lines of flux are parallel to the tube,
maximum reading will be obtained
(
B
)
.
No signal detetced.
Signal peak
detected
off-centre.
Summary of Contents for M-SCAN
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