IC-MH16_15 Datasheet, PDF (17/25 Pages) IC-Haus GmbH – 12-BIT ANGULAR HALL ENCODER

iC-MH16
12-BIT ANGULAR HALL ENCODER
preliminary
Rev A1, Page 17/25
Calibration using incremental signals
If test mode cannot be used, signals can also be cali-
brated using the incremental signals or the values read
out serially. In order to achieve a clear relationship be-
tween the calibration parameters which have an effect
on the analog sensor signals and the digital sensor val-
ues derived from these, the position of the zero pulse
should be set to ZPOS = 0x0 and the rotating direction
should be set to CFGDIR = 0x0, so that the digital signal
starting point matches that of the analog signals.
At an incremental resolution of 8 edges per revolution
(CFGRES = 0x01) those angle values can be displayed
at which calibration parameters VOSS, VOSC and GCC
demonstrate their greatest effect. When rotating the
magnet at a constant angular speed the incremental
signals shown in Figure 18 are achieved, with which
the individual edges ideally succeed one another at a
temporal distance of an eighth of a cycle (a 45 ° angle
distance). Alternatively, the angle position of the mag-
net can also be determined using a reference encoder,
rendering an even rotational action unnecessary and
allowing calibration to be performed using the available
set angle values.
The various possible effects of parameters VOSS,
VOSC and GCC on the flank position of incremental
signals A and B are shown in Figure 18. Ideally, the
distance of the rising edge (equivalent to angle posi-
tions of 0 ° and 180 °) at signal A should be exactly half
a period (PER). Should the edges deviate from this in
distance, the offset of the sine channel can be adjusted
using VOSS. The same applies to the falling edges of
the A signal which should also have a distance of half
a period; deviations can be calibrated using the offset
of cosine parameter VOSC. With parameter GCC the
distance between the neighboring flanks of signals A
and B can then be adjusted to the exact value of an
eighth of a cycle (a 45 ° angle distance).
A
B
Z
VOSS
VOSC
GCC
PER
Figure 18: Calibration using incremental signals