IC-MH Datasheet, PDF (15/23 Pages) IC-Haus GmbH – 12 BIT ANGULAR HALL ENCODER

iC-MH
12 BIT ANGULAR HALL ENCODER
Rev B1, Page 15/23
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 = 0 so that the digital signal
starting point matches that of the analog signals.
At an incremental resolution of 8 edges per revolu-
tion (CFGRES = 0x1) those angle values can be dis-
played at which calibration parameters VOSS, VOSC
and GCC demonstrate their greatest effect. When ro-
tating the magnet at a constant angular speed the in-
cremental signals shown in Figure 16 are achieved,
with which the individual edges ideally succeed one
another at a temporal distance of an eighth of a cy-
cle (a 45° angle distance). Alternatively, the angle po-
sition of the magnet 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 .
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).
The various possible effects of parameters VOSS,
VOSC and GCC on the flank position of incremental
signals A and B are shown in Figure 16. Ideally, the
Figure 16: Calibration using incremental signals