iC-MH
12 BIT ANGULAR HALL ENCODER
Rev B1, Page 16/23
Sine/Digital Converter
100%
The iC-MH module integrates two separate sine/digital
converters. A high-resolution 12-bit converter for the
ABZ incremental signals can be programmed in broad
ranges of the resolution and generate quadrature sig-
nals even at the highest speed and resolution. The
converter operates for the commutation signals inde-
pendently of this and can be set in the zero point sep-
arately from the quadrature converter. This enables
the commutation at other angles based on the index
track Z.
A
B
Z
Figure 17: ABZ signals and relative accuracy
CFGRES(7:0)
Adr 0x06; Bit 7:0
0x0
1
The incremental signals can be inverted again inde-
pendently 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.
0x1
2
...
...
0x7e
0x7f
0x80
0x81
0x82
127
128
256
512
1024
Table 15: Programming interpolation factor
Figure 17 shows the position of the incremental sig-
nals 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%.
The resolution of the 12-bit converter can virtually be
set as desired. Any resolution can be set up to an in-
terpolation factor of 128, i.e. 512 edges per rotation. At
higher resolutions, only the binary resolutions can be
set, i.e. 256, 512 and 1024. In the highest resolution
with an interpolation factor of 1024, 4096 edges per
rotation are generated and 4096 angular steps can be
differentiated. Even in the highest resolution, the abso-
lute position can be calculated in real time at the maxi-
mum speed. After the resolution is changed, a module
reset is triggered internally and the absolute position is
recalculated.
CFGHYS(1:0)
Adr 0x08; Bit 7:6
0x0
0x1
0x2
0x3
0,17°
0,35°
0,7°
1,4°
Table 17: 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 gen-
erated at the same position on the output. The fol-
lowing figure shows the generated quadrature signals
for a resolution of 360 edges per rotation (interpolation
factor 90) and a set angular hysteresis of 1.4°.
CFGAB(1:0)
Adr 0x08; Bit 1:0
A and B not inverted
B inverted, A normal
A inverted, B normal
A and B inverted
0x0
0x1
0x2
0x3
Table 16: Inversion of AB signals
ICHAUS [ IC-HAUS GMBH ]
