Faulhaber MC 5010, Communications Manual, Page: 16 / 43

3 Protocol description
15-04-2016 16 7000.05052
3.3 SDO (Service Data Object)
The SDO reads and describes parameters in the OD (object dictionary). The SDO accesses
the object dictionary via the 16-bit index and the 8-bit sub-index. At the request of the
client (PC, PLC) the Motion Controller makes data available (upload) or receives data from
the client (download).
Tab. 2: Distribution of the SDO types of transmission
Type of transmission Data length Purpose
Expedited transfer maximum 58 bytes Read and write individual numeric parameters
Segmented transfer any Transmission of data blocks (such as the trace buffer)
3.3.1 Expedited transfer
3.3.1.1 Read the object dictionary
Entries in the object dictionary can be read using the SDO read. Telegrams are always
acknowledged.
Tab. 3: Request
Byte Contents Description
1 7 User data length 7 bytes
2 Node number Node number
3 0x01 Command SDO Read
4 Index LB Index of the object entry LB
5 Index HB Index of the object entry HB
6 Sub-index Sub-index of the object entry
7 CRC Check sum
Tab. 4: Response
Byte Contents Description
1 Length User data length >7 bytes
2 Node number Node number
3 0x01 Command SDO Read
4 Index LB Index of the object entry LB
5 Index HB Index of the object entry HB
6 Sub-index Sub-index of the object entry
7–N Value Current value of the specified object entry
(N+1) CRC Check sum
If the specified object cannot be read, the response is an SDO error in accordance with
CiA301 (see chap. 3.3.3, p. 23).