BCM-MS, BCM-LS
CAN
CAN-ID
DLC
CAN message payload
0
1
2
3
4
5
6
7
CANopen SDO
COB-ID 11 bit
DLC
Cmd
Index
Subindex
CANopen SDO message payload
Tab. 22:
Structure of an SDO message
The following is an example of an SDO query of the sensor serial number from the object directory to index 0x1018, subindex 4,
with a data length of 32 bit. The client (control unit) sends a read request to the sensor with the ID "NodeID".
CAN
CAN-ID
DLC
CAN message payload
0
1
2
3
4
5
6
7
CANopen
COB-ID 11 bit
DLC
Cmd
Index
Subidx
SDO payload
1
0
0
3
2
1
0
Message from cli-
ent to sensor
0x600 +
NodelD
0x08
0x40
0x18
0x10
0x04
don't care don't care don't care don't care
Tab. 23:
SDO download request from the client to the server
The sensor responds with the corresponding SDO message encoded with the data type, index, subindex and the serial number
of the sensor, in this case serial number 200123 (0x30DBB).
CAN
CAN-ID
DLC
CAN message payload
0
1
2
3
4
5
6
7
CANopen
COB-ID 11 bit
DLC
Cmd
Index
Subidx
SDO payload
1
0
0
3
2
1
0
Message from cli-
ent to sensor
0x580 +
NodelD
0x08
0x43
0x18
0x10
0x04
0xBB
0x0D
0x30
0x00
Tab. 24:
SDO download response from the server to the client
The following is an example of a data upload (heartbeat time) via SDO to the object directory of the sensor to index 0x1017 with
a data length of 16 bit. The client (control unit) sends a write request to the sensor with the ID "NodeID” to set the heartbeat time
to 1000°ms (0x03E8).
CAN
CAN-ID
DLC
CAN message payload
0
1
2
3
4
5
6
7
CANopen
COB-ID 11 bit
DLC
Cmd
Index
Subidx
SDO payload
1
0
0
3
2
1
0
Message from cli-
ent to sensor
0x600 +
NodelD
0x08
0x2B
0x17
0x10
0x00
0xE8
0x03
0
0
Tab. 25:
SDO upload request from the client to the server
The sensor responds with the corresponding SDO message confirming successful access and the index and subindex accessed
are encoded.
CAN
CAN-ID
DLC
CAN message payload
0
1
2
3
4
5
6
7
CANopen
COB-ID 11 bit
DLC
Cmd
Index
Subidx
SDO payload
1
0
0
3
2
1
0
Message from cli-
ent to sensor
0x580 +
NodelD
0x08
0x60
0x17
0x10
0x00
0x00
0x00
0x00
0x00
Tab. 26:
SDO upload response from server to client
28
Bühler Technologies GmbH
BE150104 ◦ 03/2021