IC-MU_13 Datasheet, PDF (36/59 Pages) IC-Haus GmbH – OFF-AXIS NONIUS ENCODER WITH INTEGRATED HALL SENSORS

iC-MU OFF-AXIS NONIUS ENCODER
WITH INTEGRATED HALL SENSORS
preliminary
Rev B1, Page 36/59
LIN
Code
0
1
Addr. 0x0E; bit 4
Description
Rotative
Linear
Table 49: Selection of linear/rotative hall sensors
An offset between the nonius track and the mas-
ter track within one revolution can be adjusted with
SPO_BASE and SPO_x (x=0-14) .
The following formula describes how the error curve
based on the raw data from the master and nonius
track can be calculated. 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 50. For the tolera-
ble phase deviation of a 3-track nonius system please
reffer to Table 64 page 40.
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 50: Tolerable phase deviation for the master ver-
sus the nonius track of a 2 track nonius sys-
tem (with reference to 360°, electrical)
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
function 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
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 abso-
lute position given by the nonius difference (master-
nonius).
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 51: Nonius track offset start value
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 )
P₁₄
x =0
SPO_x
= {−7 ... 7} ∗ (22.5°/2^MPC )
Table 52: Nonius track offset slopes
SPO_15(3:0)
Addr. SER:0x5A; bit 3:0
Code
Slope
0x0
-
...
is
automatically
computed:
−
P₁₄
x =0
SPO_x
0xF
-
Note
internal register, not readable via serial interface
Table 53: Nonius track offset slope (is automatically
computed)
The principle is shown in Figure 30. The red curve cor-
responds to the error curve of the nonius difference ab-
solute 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