IC-MU_17 Datasheet, PDF (41/66 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 41/66
MT INTERFACE
MTC
MTD
MSB
LSB
MODE_MT + SBL_MT + ESSI_MT
ttos
Figure 36: Example of multiturn SSI line signals
Configuration of the Multiturn interface
iC-MU can read and synchronize binary data from an
external SSI sensor through the serial multiturn inter-
face. On startup the first data value read in determines
the start value of the internal MT counter. After startup
the multiturn counter counts the ST cycles. If there is
an error reading the external multiturn during startup,
the read-in will be repeated.
multiturn-
startup
MODE_MT(3:0) Addr. 0x10; bit 3:0
Code
Function
Code
Function
0x0
no external data 0x8
4 *) + 12 bit
0x1
1 *) bit
0x9
5 *) + 12 bit
0x2
2 *) bit
0xA
6 *) + 12 bit
0x3
3 *) bit
0xB
4 bit
0x4
4 *) bit
0xC
8 bit
0x5
5 *) bit
0xD
12 bit
0x6
6 *) bit
0xE
16 bit
0x7
3 *) + 12 bit
0xF
18 bit
Notes:
*) data interpreted as ST
If MPC ≥ 0x07 than MODE_MT has to be set to 0x0
or 0xD
Table 60: MT interface operating mode
For synchronization a synchronization bit length must
be set with SBL_MT. Synchronization takes place be-
tween the external multiturn data read in and the ST
period information counted internally (see Fig. 39). Syn-
chronization can take place automatically within the
relevant phase tolerances.
read external
multiturn
serial-communication error? ^yes
no
sync to ST period information
and preset MT counter
set MT_ERR
proceed with
startup-sequence
Figure 37: Error handling during startup
SBL_MT(1:0)
Addr. 0x10; bit 5:4
Code
MT synchronisation bit synchronisation
length
tolerance (ST-resolution)
0x0
1 bit
± 90°
0x1
2 bit
± 90°
0x2
3 bit
± 135°
0x3
4 bit
± 157,5°
Table 61: MT synchronization bit length
Figure 38 shows the principle of a 2 bit MT synchroniza-
tion for ideal signals (without indication of synchroniza-
tion tolerance limits).
If the MT interface is not used (MODE_MT = 0x0), the
internal 24-bit MT counter can extend the singleturn
information to include the counted ST cycles.
ST MSB -1
180° 270° ^{0° 90°} 180° 270° ^{0° 90°}
For exclusive multiturn systems a 4, 8, 12, 16 or
18-bit multiturn data value can be read in (MODE_MT =
0xB-0xE).
There is also the possibility to interpret a part of
the external multiturn data value as singleturn data
(MODE_MT = 0x1-0xA). This influences the incremen-
tal output signals, UVW commutation signals and data
output in MODE_ST = 0x01 (FlexCount®). For further
information see Construction of a Multiturn system
with two iC-MU S. 43.
ST MSB
MT LSB -2
MT LSB -1
MT LSB
multiturn
data output
°/ST
Figure 38: Principle of 2 bit MT synchronization