IC-MH_17 Datasheet, PDF (15/26 Pages) IC-Haus GmbH – 12-BIT ANGULAR HALL ENCODER

iC-MH
12-BIT ANGULAR HALL ENCODER
set more accurately by varying GAINF. Variations in the
gain factor, as shown in figure 12, have no effect on the
Lissajous curve, while enabling the angle information
for the interpolator to be maintained.
V_sin
GAING
GAINF
Rev C2, Page 15/26
V_sin
VOSS
α
V_cos
α
V_cos
C141107-2
Figure 12: Effect of gain settings GAING and GAINF
Deviations of the observed Lissajous curve from the
ideal circle can be corrected by varying the amplitude
offset (register VOSS, VOSC) and amplitude ratio (reg-
ister GCC). Changes in these parameters are described
in the following figures 13 to 15. Each of these settings
has a different effect on the interpolated angle value. A
change in the sine offset thus has a maximum effect on
the angle value at 0° and 180°, with no alterations what-
soever taking place at angles of 90° and 270°. When
varying the cosine offset exactly the opposite can be
achieved as these angle pairs can be set independent
of one another. Setting the cosine/sine amplitude ratio
does not change these angles (0°, 90°, 180° and 270°);
however, inbetween values of 45°, 135°, 225° and 315°
can still be influenced by this parameter.
C141107-3
Figure 13: Effect of the sine offset setting
V_sin
VOSC
α
V_cos
C141107-4
Figure 14: Effect of the cosine offset setting
V_sin
GCC
Once calibration has been carried out a signal such as
the one illustrated in figure 11 should be available.
In the final stage of the process the amplitude control
can be switched back on (ENAC =1) to enable devia-
tions in the signal amplitude caused by variations in the
magnetic field due to changes in distance and tempera-
ture to be automatically controlled.
α
V_cos
C141107-5
Figure 15: Effect of the amplitude ratio