IC-PV Datasheet, PDF (14/28 Pages) IC-Haus GmbH – BATTERY-BUFFERED HALL MULTITURN ENCODER

iC-PV
BATTERY-BUFFERED HALL MULTITURN ENCODER
SERIAL INTERFACE (SEL = LOW)
Rev E2, Page 14/28
iC-PV can connect to an external singleturn sensor via
a serial interface. To ensure compatibility with different
types of singleturn sensors, the iC-PV’s serial interface
can operate in two distinct modes. These are a stan-
dard SSI conform operating mode and a chain mode,
respectively.
By default, the iC-PV expects the serial input at the data
in pin (DI) to be binary. Similarly it outputs its counted
multiturn position via DO in binary format. In case one
of them or both are required to be in gray format, this
can be configured by setting the ST_GRAY bit or the
MT_GRAY bit, respectively.
In the SSI mode, the iC-PV expects an external sin-
gleturn sensor to request the multiturn data via a SSI
protocol. The singleturn sensor takes care of synchro-
nization and calculates a consistent absolute position.
The data in pin (DI) is not used in this operating mode.
iC-PV is compatible with all iC-Haus optical or mag-
netic singleturn encoders featuring a multiturn interface
(MTI). For details please refer to application examples
in Figure 12 up to Figure 15.
In this mode of operation, iC-PV can also be used as
stand-alone magnetic revolution counter. The position
can be read via a serial, SSI compatible protocol (see
Figure 17).
ST_GRAY
Code
0
1
Addr. 0x00; bit 2
Format
Binary code
Gray code
Table 10: Singleturn input data format via pin DI
MT_GRAY
Code
0
1
Addr. 0x00; bit 1
Format
Binary code
Gray code
Table 11: Multiturn output data format via pin DO
In the chain mode, the singleturn sensor transmits the
singleturn position first to the iC-PV via the data in pin
(DI). In this configuration, the iC-PV takes care of syn-
chronization, calculates a consistent absolute position
and outputs it concurrently (MSB first) via the data out
pin (DO), comparable to a shift register. To synchronize
the incoming singleturn position word and its internal
multiturn position, the iC-PV samples the singleturn
MSB with the first rising edge of CLK. Therefore, in
chain mode, it is mandatory to use a singleturn encoder
architecture capable to provide the MSB at this instant
of time (see Figure 9). From iC-Haus portfolio these
are the iC-LNG and iC-LNB singleturn encoders. They
use an additional NSEL signal to latch the MSB before
communication starts. Please refer to their datasheets
for details. An application example with iC-LNG as
singleturn iC is shown in Figure 16.
The respective mode to operate in is set using parame-
ter INT_MODE.
INT_MODE
Addr. 0x00; bit 0
Code
Mode
0
Standard SSI readout mode (SSI)
1
Chain mode (CHAIN)
Table 9: Serial interface operating mode
The width of the internal multiturn counter is 40 bit. In
applications where smaller counter depths are sufficient
or are restricted by the bit width of the serial interface,
the output length of the counter value can be configured
with MT_BW as shown in Table 12.
MT_BW
Code
0x00
0x01
.
0x1E
0x1F
Addr. 0x01; bit 4:0
Bit width
9 bit
10 bit
...
39 bit
40 bit
Table 12: Multiturn bit width
Additionally iC-PV can transmit up to 3 synchronization
bits, according to configuration parameter SYNC_BW
shown in Table 13.
SYNC_BW
Code
00
01
10
11
Addr. 0x02; bit 1:0
Bit width
Phase shift range
0 bit
no synchronization bit
1 bit
0 °... 180 °
2 bit
0 °... 270 °
3 bit
0 °... 315 °
Table 13: Synchronization bit width and resulting toler-
able ideal phase shift