Wachendorff WDGA CANopen, Technical Manual, Page: 58 / 82

Technical Manual
WDGA with CANopen-Interface
8 - Setting-up the encoder
© Wachendorff Automation GmbH & Co. KG 47 Rev.1.24
8.3.2 SDO access on objects larger than 4 bytes
As seen in subsection 8.3.1 the payload of a single (expedited) SDO is 4byte. For
larger data there is the possibility of a "normal" segmented SDO transfer or block
transfer for up to 127 segments of 4 byte. For example you want to to read the "high
precision preset position value (Obj. 6008h)" or perform a "high precision preset
(Obj. 6009h)", so you have to use the segmented SDO transfer.
Segmented read access on an object:
Figure 8.3: Segmented SDO read access
In the following example the 8byte "High Precision Position Value" (object 6008h) is
read:
600h+ID 8
40h
01000000b
ccs=2,e=0,
s=0 08h 06h 00h 00h 00h 00h 00h
CAN-ID DLC Command Object
L
Object
H Sub-
Index Byte0 Byte1 Byte2 Byte3
Table 8.17: SDO read request on object 6008h