Overview 07/06 Danaher Motion
10 Initial Release M-S2-021-11
2.4.5. S
ERVICE
D
ATA
O
BJECTS
(SDO)
SDOs are used to implement access to the Object Dictionary. The SDOs are required for parametrerization
and for status polling. Access to an individual object is made with a multiplexer via the Index and Subindex
of the Object Dictionary. The following communication protocols are supported by the S200:
Initiate SDO Download Protocol
Download SDO Segment Protocol
Initiate SDO Upload Protocol
Upload SDO Segment Protocol
Abort SDO Transfer Protocol
The definitions of the individual communication services and protocols can be found in DS301. Examples
of the usage of SDOs can be found in the application note, CANOpen for S200 Setup and Application
Examples.
NOTE
Since an SDO is a confirmed service, the system must always wait for the SDO
response telegram before it is allowed to transmit a new telegram
Composition of the Service Data Object
An SDO consists of the following components:
Byte 1 2 3 4 5 6 7 8
Content rw Index SubIndex Data
1. The control byte (Byte 1):
The control byte determines whether the SDO should write or read the content of the entry in the
Object Dictionary (see Appendix).
Data exchange with the S200 is governed by the CMS multiplexed domain protocols standard, as
described in the CAN standard DS 202.
To read data, the control byte must be written in the manner shown below:
Bit 7 6 5 4 3 2 1 0
Content ccs*=2 X X X X X
*ccs client command specifier (ccs = 2 initiate upload request)
X free data
So a value of 0100 0000 (binary) or 40h has to be transmitted in the control byte.
The servo amplifier sends back a corresponding response byte:
Bit 7 6 5 4 3 2 1 0
Content scs*=2 X n e s
*scs server command specifier (scs = 2 initiate upload response)
n only valid for e = s = 1
if this is so, n contains the number of bytes that do not contain data
X free data
If reading is successful, the response byte always has set the bits 0 and 1 (e = s = 1).
Encoded byte length in the SDO response:
0x43 - 4 bytes
0x47 - 3 bytes
0x4B - 2 bytes
0x4F - 1 byte.
