Issue 01/05 Data transfer using CANopen
CANopen Option Module Operating Instructions
6SE6400-5BC00-0BP0
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3.2.4 SDO (Service Data Object) services
SDO services are used to access the object directory of the connected device. An
SDO connection is a peer-to-peer coupling between an SDO client and a server.
The MICROMASTER with its object directory is, in this sense, an SDO server. The
identifiers of the Micromaster are defined according to CANopen. For
communications between the client => server, then COB-ID 600H + node ID and
for the server => client, COB-ID 580H + node ID apply.
Properties/features of SDOs
• Confirmed transfer of objects
• Data transfer/exchange is always asynchronous (non-synchronous)
• Values greater than 4 bytes can be transferred (normal transfer)
• Values not more than 4 bytes can be transferred (expedited transfer)
All variables of the drive can be addressed via SDO transfer.
Note
For MICROMASTER, SDO transfer is only possible by specifying the length of the
data bytes contained. If another device uses the transfer mechanism without length
data, then problems can occur.
Downloading SDO protocol
The download SDO protocol is used to write the values of the object directory into
the drive. MICROMASTER 420/430/440 only supports the "expedited SDO
download" for up to 4 bytes of data (e =1,s = 1).
0 1 2 3 4 7
CLIENT SERVER
Request
Indication
7 ... 5
ccs = 1
4
x
Index
Sub-
index
Data
0 1 2 3 4 7
Confirm
Response
7 ... 5
scs = 3
4 ... 0
x
Index
Sub-
index
reserved
3 ... 2
n
1
e
0
s
Fig. 3-7 Download SDO protocol
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