IC-MU_17 Datasheet, PDF (39/66 Pages) IC-Haus GmbH – MAGNETIC OFF-AXIS POSITION ENCODER - POLE WIDTH 1.28MM

iC-MU MAGNETIC OFF-AXIS
POSITION ENCODER - POLE WIDTH 1.28MM
Rev D1, Page 39/66
LIN
Code
0
1
Addr. 0x0E; bit 4
Hall sensor Type of target magnetization
arrangement
Rotative
Axial (e.g. MU2S 30-32N)
Linear
Radial (e.g. MU7S 25-32N) or
Linear (e.g. MUxL)
Table 53: Selection of linear/rotative hall sensors
An offset between the nonius track and the master track
within one revolution can be adjusted with SPO_BASE
and SPO_x (x=0-14) .
SPO_BASE(3:0) Addr. 0x19; bit 3:0
SPO_BASE(3:0) Addr. SER:0x52; bit 3:0
Code
Starting point referred to 1 revolution
0x0
0 * (22.5°/2^MPC)
...
...
0x7
7 * (22.5°/2^MPC)
0x8
-8 * (22.5°/2^MPC)
0x9
-7 * (22.5°/2^MPC)
...
...
0xF
-1 * (22.5°/2^MPC)
Table 55: Nonius track offset start value
The following formula describes how the error curve
based on the raw data from the master and nonius track
can be calculated. 2^MPC is the number of sine periods
of the measuring distance.
2^MPC
TOL_SPON = RAW_MASTER − RAW_NONIUS ∗ _{2MPC − 1}
The maximum tolerable phase deviation for a 2-track
nonius system is shown in Table 54. For the tolerable
phase deviation of a 3-track nonius system please refer
to Table 68 page 43.
Periods/revolution
Master Nonius
16
15
32
31
64
63
Permissible Max. Phase Deviation
[given in degree per signalperiod of 360°]
Master ↔ Nonius
+/- 9.84°
+/- 4.92°
+/- 2.46°
Table 54: Tolerable phase deviation for the master ver-
sus the nonius track of a 2 track nonius sys-
tem (with reference to 360°, electrical)
SPO_0(3:0)
Addr. 0x19; bit 7:4
Addr. SER: 0x52
SPO_1(3:0)
Addr. 0x1A; bit 3:0
Addr. SER: 0x53
SPO_2(3:0)
Addr. 0x1A; bit 7:4
Addr. SER: 0x53
SPO_3(3:0)
Addr. 0x1B; bit 3:0
Addr. SER: 0x54
SPO_4(3:0)
Addr. 0x1B; bit 7:4
Addr. SER: 0x54
SPO_5(3:0)
Addr. 0x1C; bit 3:0
Addr. SER: 0x55
SPO_6(3:0)
Addr. 0x1C; bit 7:4
Addr. SER: 0x55
SPO_7(3:0)
Addr. 0x1D; bit 3:0
Addr. SER: 0x56
SPO_8(3:0)
Addr. 0x1D; bit 7:4
Addr. SER: 0x56
SPO_9(3:0)
Addr. 0x1E; bit 3:0
Addr. SER: 0x57
SPO_10(3:0)
Addr. 0x1E; bit 7:4
Addr. SER: 0x57
SPO_11(3:0)
Addr. 0x1F; bit 3:0
Addr. SER: 0x58
SPO_12(3:0)
Addr. 0x1F; bit 7:4
Addr. SER: 0x58
SPO_13(3:0)
Addr. 0x20; bit 3:0
Addr. SER: 0x59
SPO_14(3:0)
Addr. 0x20; bit 7:4
Addr. SER: 0x59
Code
Slope referred to 1 revolution
0x0
0 * (22.5°/2^MPC)
...
...
0x7
7 * (22.5°/2^MPC)
0x8
-8 * (22.5°/2^MPC)
0x9
-7 * (22.5°/2^MPC)
...
...
0xF
Note
-1 * (22.5°/2^MPC)
14
x=0
SPO_x
= {−7 ... 7} ∗ (22.5°/2^MPC)
An offset correction curve can be specified with
SPO_BASE and SPO_x (x = 0-14). SPO_BASE is the
start-value. SPO_0 to SPO_14 can be interpreted as
slope-values. A change in the slope of the offset func-
tion can be made each 22.5°. The slope value SPO_15
is computed automatically by iC-MU. To do this the
following condition must be met:
14
SPO_x = {−7 ... 7}
x=0
Table 56: Nonius track offset slopes
SPO_15(3:0)
Addr. SER:0x5A; bit 3:0
Code
Slope
0x0
-
...
is automatically computed: −
14
x=0
SPO_x
0xF
-
Note
internal register, not readable via serial interface
Table 57: Nonius track offset slope (is automatically
computed)
The offset value between to slopes (e.g. SPO_0 and
SPO_1) is interpolated. The computed offset is added
to the converted result of the nonius track prior to syn-
chronization and is used to calibrate the nonius to the
master track. An offset value is chosen by the absolute
position given by the nonius difference (master-nonius).
The principle is shown in Figure 33. The red curve
corresponds to the error curve of the nonius difference
absolute within 360°. By taking the blue marked SPO_x
curve it is shown, that the nonius difference can be
changed in a way that the resulting green curve is in
the valid synchronisation range. It can be seen that