IC-MH8_14 Datasheet, PDF (18/25 Pages) IC-Haus GmbH – 12 BIT ANGULAR HALL ENCODER

iC-MH8
12 BIT ANGULAR HALL ENCODER
Sine/Digital Converter
The iC-MH8 module integrates a high-resolution
sine/digital converter. In the highest output resolution
with an interpolation factor of 1024, 4096 edges per
rotation are generated and 4096 angular steps can be _A
differentiated. Even in the highest resolution, the abso-
lute position can be calculated in real time at the max-
imum speed.
B
preliminary
Rev A1, Page 18/25
100%
This absolute position is used to generate quadrature
signals (ABZ) and commutation signals (UVW). The
zero point of the quadrature signals and the commu-
tation signals can be set separately. This enables the
commutation at other angles based on the index track
Z.
Z
Figure 17: ABZ signals and relative accuracy
The resolution of the incremental output signals is pro-
grammed with CFGRES.
The value of the 12-bit sine-digital converter is avail-
able in full resolution in the ’Extended SSI-Mode’ and
in a resolution according to CFGRES in the ’SSI-
Mode’.
CFGRES(2:0)
0x0
1024
0x1
512
0x2
256
0x3
128
0x4
64
0x5
32
0x6
16
0x7
8
0x8
4
0x9
2
0xA
1
Addr. 0x06; bit 3:0
Table 15: Programming interpolation factor
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.
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%.
CFGHYS(1:0)
0x0
0,17^◦
0x1
0,35^◦
0x2
0,7^◦
0x3
1,4^◦
Addr. 0x08;
bit 7:6
Table 17: Programming angular hysteresis
After the resolution is changed, a module reset is trig-
gered internally and the absolute position is recalcu-
lated.
CFGAB(1:0)
Addr. 0x08; bit 1:0
0x0
A and B not inverted
0x1
B inverted, A normal
0x2
A inverted, B normal
0x3
A and B inverted
Table 16: Inversion of AB signals
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^◦.