Description of CANopen-Interface
HYDAC ELECTRONIC GMBH
07.10.2010
Mat. No. 669824
Page 17 of 63
Segment Protocol, Data segmentation
Some objects contain data which are larger than 4 bytes. To be able to read these
data, the "Segment Protocol" must be used.
As a usual SDO service, at first the read operation is started with the command
code = 0x40. About the response the number of data segments and the number of
bytes to be read is reported. With following reading requests the individual data
segments can be read. A data segment consists respectively of 7 bytes.
Example of reading a data segment:
Telegram 1
CCD
Meaning
Valid for
0x40
Reading request, initiation
SDO Request
0x41
1 data segment available
The number of bytes which can be read is indicated in
the bytes 4 to 7.
SDO Response
Telegram 2
CCD
Meaning
Valid for
0x60 Reading
request
SDO
Request
0x01
No further data segment available.
The bytes 1 to 7 contain the requested data.
SDO Response