•
SDO Download Expedited (write SDO)
•
SDO Upload Expedited (read SDO)
•
Upload SDO Segment Protocol (segmented reading of an SDO)
SDO Download Expedited (write SDO)
The client sends a request to server N. The 16-bit index and the subindex for the SDO
to be written are contained in this message. The request additionally contains four data
bytes with the data to be written.
Table 35: Write SDO
CAN-ID
DLC
Data
600h + N
8
23h
SDO_L
SDO_H
SUB
Byte 1
Byte 2
Byte 3
Byte 4
SDO_L = SDO index, low byte
SDO_H = SDO index, high byte
SUB = SDO subindex
The server then replies with a confirmation message:
Table 36: SDO write confirmation
CAN-ID
DLC
Data
580h + N
8
60h
SDO_L
SDO_H
SUB
Byte 1
Byte 2
Byte 3
Byte 4
Bytes 1 to 4 in the write confirmation message contain zeros.
SDO Upload Expedited (read SDO)
The client requests the content of an SDOs with a request to server N. The 16-bit index
and the subindex for the SDO to be read are contained in this message. Bytes 1 to 4 in
the read request message contain zeros.
Table 37: Read SDO
CAN-ID
DLC
Data
600h + N
8
40h
SDO_L
SDO_H
SUB
Byte 1
Byte 2
Byte 3
Byte 4
The server replies with the following message: Bytes 1 to 4 contain the value of the
requested object.
Table 38: SDO read confirmation
CAN-ID
DLC
Data
580h + N
8
43h
SDO_L
SDO_H
SUB
Byte 1
Byte 2
Byte 3
Byte 4
The CANopen data types UDINT and UINT
To transmit the data types UDINT or UINT, the data must be in Intel format or Little
Endian. For example, the 32-bit value 12345678h in the data bytes 5, 6, 7 and 8 must
be transmitted in the following sequence: [5] = 78, [6] = 56, [7] = 34, [8] = 12.
NOTE
This applies also to the SDO index in data byte 2 and 3, which has the data type UINT.
That is, the low byte is transferred in data byte 2 and the high byte is transferred in data
byte 3.
Example:
The following messages are required to read SDO 1003.1h of the CANopen
device with the node ID 2. The data type of the data to be read is UDINT.
The client sends:
4
PROJECT PLANNING
42
O P E R A T I N G I N S T R U C T I O N S | scanGrid2 CANopen
8025990/2021-03-03 | SICK
Subject to change without notice