Sdo (Service Data Object) Services - Siemens MICROMASTER 420 Operating Instructions Manual

Issue 01/05
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).
CLIENT
Request
Confirm
Fig. 3-7
CANopen Option Module Operating Instructions
6SE6400-5BC00-0BP0
0
7 ... 5 4 3 ... 2
ccs = 1 x n
0 1
7 ... 5 4 ... 0
Index
scs = 3 x
Download SDO protocol
Data transfer using CANopen
1 2 3 4
1 0 Sub-
Index
Data
e s
index
2 3 4
Sub-
reserved
index
SERVER
7
Indication
7
Response
37