SD710 Series Servo Drive User Manal Chapter 11 Communication
12
inquiry
answer
Figure 11-4 SDO client reading-writing the object dictionary in the SDO server
11.2.3.2 SDO transmission format
SDO transmission is divided into object data transmission of no more than 4 bytes and higher than 4 bytes. Accelerated
SDO transmission mode shall be adopted when it is not higher than 4 bytes, and segmented transmission or block
transmission mode shall be adopted when it is higher than 4 bytes. Sd710 series drives only support accelerated SDO
transmission. The SDO communication message is basically composed of COBID + command code + index + Sub index
+ data. The data segment adopts the "small-end mode", i.e., the low bit is in the front and the high bit is in the back.
The
format of SDO transmission message is shown in table 11-20.
Table 11-20 SDO Transmission Messages
COB-ID
0
1
2
3
4
5
6
7
600h+Node_ID
command
code
index
Sub index
data area
580h+Node_ID
index
Sub index
data area
For example,
The data area needs to send or receive data as 32-bit 0x11223344, which is arranged as 44 33 22 11 when sending or
receiving.
(1) SDO accelerated write transmission message
For reading and writingienot higher than 4 bytes, accelerated SDO transmission is used. The transmission messages
vary according to the inconsistency of the read/write method and data length. The format of the accelerated SDO write
message is shown in Table 11-21.
Table 11-21 Explanation of Accelerated SDO Message Format
COB-ID
0
1
2
3
4
5
6
7
client side
→
600h+Node_ID
23H
index
Sub index
data
2BH
data
-
-
2FH
data
-
-
-
server
←
580h+Node_ID
60H
index
Sub index
-
-
-
-
80H
Abort Code
Note: 1. "-" means data is available but not considered, and it is recommended to write 0 when writing data.
SDO Client
SDO Server
Terminal
data
data
