Wieland samos PRO COMPACT - SDO Communication

CANopen gateway
Wieland Electric GmbH | BA000970 | 11/2016 (Rev. F)
147
SDO communication
910841739
SDOs are service data objects. They contain a wide spectrum of different data. This includes
configuration as well as input and output data.
Contrary to PDO communication, the receipt of each SDO is answered at protocol level,
i.e. the receiving device sends a confirmation.
This CANopen PCS implementation supports the following protocols:
• 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 an the sub-index for the SDO to be
written form part of this message. In addition, the request contains 4 data bytes with the data
to be written.
Table 96: 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 responds with a confirmation:
Table 97: SDO write confirmation
CAN ID
DLC
Data
580h + N
8
60h
SDO_L
SDO_H
SUB
Byte 1
Byte 2
Byte 3
Byte 4
Byte 1 to 4 in the write confirmation contain zeros.
SDO Upload Expedited (read SDO)
The client requests the content of an SDO by submitting a request to server N. The 16-bit index
and the sub-index for the SDO to be read form part of this message. Byte 1 to 4 in the read re-
quest contain zeros.
Table 98: 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 responds with the following message. Bytes 1 to 4 contain the value of the reques-
ted object.
Table 99: SDO read confirmation
CAN ID
DLC
Data
580h + N
8
42h
SDO_L
SDO_H
SUB
Byte 1
Byte 2
Byte 3
Byte 4
10.9