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IC-MA Datasheet, PDF (8/18 Pages) IC-Haus GmbH – ANGULAR HALL SENSOR / ENCODER | |||
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iC-MA
ANGULAR HALL SENSOR / ENCODER
The sensor principle
Rev B3, Page 8/18
S
N
cal, diametrically magnetized permanent magnet (with
a diameter D of 4 mm and length L of 4 mm, for exam-
ple) provides optimal sensor signals. Magnetic materi-
als such as neodymium iron boron (NdFeB) or samar-
ium cobalt (SmCo) are very well suited to the sensor
and not readily inï¬uenced by external magnetic distur-
bance ï¬elds. The L/D ratio of a magnet magnetized
to saturation point has a bearing on the resulting ï¬eld
strength and should lie within the region of 0.3 to 2.
zy
B
+Bz
x
-Bz
Figure 4: The principle of magnetic ï¬eld measure-
ment using a Hall sensor
In conjunction with a permanent magnet iC-MA can be
used to create a complete encoder system. A cylindri-
iC-MA has four Hall sensors which are used to deter-
mine angles and to convert the magnetic ï¬eld into a
measurable Hall voltage. Only the z component of the
magnetic ï¬eld is assessed where the line of magnetic
ï¬ux must pass through two facing Hall sensors in the
opposite direction. An example line of magnetic ï¬ux
is given in Figure 4. The Hall sensors have been ar-
ranged in such a way that the assembly of the mag-
net with iC-MA is extremely tolerant. Two Hall sen-
sors combined generate a differential Hall signal. If
the magnet is rotated along its longitudinal axis sine
and cosine output voltages are created which can be
used to determine angles.
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