AM58K CANopen®
6.7 SDO objects
SDO messages are used to set and read values from the object dictionary of the
encoder. These parameters are described in the “Object dictionary” section (page
28).
4 bytes at the most are used for CAN data, other 4 bytes are used for Command,
Index and Sub-index fields. SDO messages are always followed by confirmation.
It follows that when Master sends a SDO message to Slave, slave always sends a
reply (and a warning, should an error occur).
SDO structure:
IDENTIFIER
from 4 to 8 CAN data bytes
COB-ID(hex)
0
1
2
3
4
5
6
7
F.C. Node-ID
Com
Index
Sub
Data
1byte
LSB
MSB 1byte
LSB
…
…
MSB
Com
command
Index
parameter index
Sub
parameter sub-index
Data
parameter value
6.7.1 Command
The command byte contains the type of telegram transmitted to the CAN
network.
Three types of telegram are available:
Set: to send configuration parameters to a device;
Req: used by master to read data from a device;
Warnings: used by slave to send error messages to master (e.g.
Index does
not exist
, …).
Command
COB
COB type
Data length
22h
Set
M
S request
not spec.
23h
Set
M
S request
4 byte
2Bh
Set
M
S request
2 byte
2Fh
Set
M
S request
1 byte
60h
Set
S
M confirmation
0 byte
40h
Req
M
S request
0 byte
42h
Req
S
M reply
not spec.
43h
Req
S
M reply
4 byte
4Bh
Req
S
M reply
2 byte
4Fh
Req
S
M reply
1 byte
41h
Req
S
M reply segmented SDO
80h
Warning
S
M reply
4 byte
MAN AM58K CB E 1.1.odt
27
6 - CANopen® interface
