IC-MH16_15 Datasheet, PDF (18/25 Pages) IC-Haus GmbH – 12-BIT ANGULAR HALL ENCODER

iC-MH16
12-BIT ANGULAR HALL ENCODER
preliminary
Rev A1, Page 18/25
SINE/DIGITAL CONVERTER
The iC-MH16 module integrates a high-resolution
sine/digital converter. In the highest output resolution
with an interpolation factor of 1 024, 4 096 edges per
rotation are generated and 4 096 angular steps can _A
be differentiated. Even in the highest resolution, the
absolute position can be calculated in real time at the
maximum speed depending on CFGMTD. After pro- B
gramming a register at address 4 to 9, a module reset
is triggered internally and the absolute position is recal-
culated.
Z
100%
The resolution of the incremental output signals is
programmed with CFGRES. The value of the 12-bit
sine/digital converter is available in a resolution accord-
ing to CFGRES via the serial interface.
CFGRES(7:0)
CFGRES(9:8)
0x000
1
0x001
2
...
...
0x07E
127
0x07F
128
...
...
0x0FE
255
0x0FF
256
...
...
0x1FE
511
0x1FF
512
...
...
0x3FE
1023
0x3FF
1024
Addr. 0x06; bit 7:0
Addr. 0x07; bit 1:0
Table 16: Programming interpolation factor
Figure 19: ABZ signals and relative accuracy
The incremental signals can be inverted again indepen-
dently of the output drivers. As a result, other phase
angles of A and B relative to the index pulse Z can be
generated. The standard is A and B high level for the
zero point, i.e. Z is equal to high.
Figure 19 shows the position of the incremental signals
around the zero point. The relative accuracy of the
edges to each other at a resolution setting of 10 bit is
better than 10 %. This means that, based on a period
at A or B, the edge occurs in a window between 40 %
and 60 %.
CFGHYS(1:0)
Addr. 0x07; bit 7:6
0x0
0°
0x1
0.17 °
0x2
0.35 °
0x3
0.7 °
If the magnet is mounted on top of the chip and turned
counter clockwise, then cosine is leading sine and the
digital output value increases. For incremental output,
A is assigned to sine and B is assigned to cosine.
CFGAB(1:0)
Addr. 0x07; bit 3:2
0x0
A and B not inverted
0x1
A normal, B inverted
0x2
A inverted, B normal
0x3
A and B inverted
Table 17: Inversion of AB signals
Table 18: Programming angular hysteresis
With rotating direction reversal, an angular hysteresis
prevents multiple switching of the incremental signals
at the reversing point. The angular hysteresis corre-
sponds to a slip which exists between the two rotating
directions. However, if a switching point is approached
from the same direction, then the edge is always gener-
ated at the same position on the output. The following
Figure shows the generated quadrature signals for a
resolution of 360 edges per rotation (interpolation factor
90) with hysteresis.