IC-MHL200 Datasheet, PDF (20/33 Pages) IC-Haus GmbH – 12-BIT LINEAR / ROTARY POSITION HALL ENCODER

iC-MHL200
12-BIT LINEAR / ROTARY POSITION HALL ENCODER
are as close to 2 V as possible. The amplitude can then
V_sin
be set more accurately by varying GAINF. Variations in
the gain factor, as shown in Figure 16, have no effect
on the Lissajous curve, enabling the angle information
for the interpolator to be maintained.
V_sin
GAING
GAINF
Rev C1, Page 20/33
VOSS
α
V_cos
α
V_cos
C141107-3
Figure 17: Effect of the sine offset setting
V_sin
VOSC
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Figure 16: 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 17 to 19. 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
whatsoever 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 indepen-
dent of one another. Setting the cosine/sine amplitude
ratio does not change these angles (0 °, 90 °, 180 ° and
270 °); however, in-between values of 45 °, 135 °, 225 °
and 315 ° can still be influenced by this parameter.
Once calibration has been carried out a signal such as
the one illustrated in Figure 15 should be available.
α
V_cos
C141107-4
Figure 18: Effect of the cosine offset setting
V_sin
GCC
α
V_cos
In the final stage of the process the amplitude control
can be switched back on (ENAC = 1) to enable de-
viations in the signal amplitude caused by variations
in the magnetic field due to changes in distance and
temperature to be automatically controlled.
C141107-5
Figure 19: Effect of the amplitude ratio
Calibration Using Incremental Signals
If test mode cannot be used, signals can also be cali-