Datalogic AMT58 Series Manual page 313

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.
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
COB-ID(hex)
F.C
Node-ID Com
.
1byt
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, ...).
Comman
COB
d
22h Set
23h Set
2Bh Set
2Fh Set
60h Set
40h Req
42h Req
43h Req
4Bh Req
4Fh Req
from 4 to 8 CAN data bytes
0 1 2
Index Sub
LSB MSB 1byte
e
COB type
M  S request
M  S request
M  S request
M  S request
S  M confirmation
M  S request
S  M reply
S  M reply
S  M reply
S  M reply
AMT58x-CB CANopen®
3 4 5
Data
LSB ...
Data length
not spec.
4 byte
2 byte
1 byte
0 byte
0 byte
not spec.
4 byte
2 byte
1 byte
6 7
... MSB
19