Datalogic AMT58 Series, Manual

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AMT58x-CB CANopen®
19
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 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
1byt
e
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 , …).
Comman
d
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