32
3 SLMP
3.4 CiA 402 read/write command
SDO Upload (CiA 402 object read)
When the slave stations (servo amplifiers) receive the CiA 402 object read request from the master station (external device),
they return a value of the object corresponding to the specified Index or Sub Index.
Request message (command and the following)
Response message
• At normal completion (end code and the following)
• At abnormal completion
The response message is the same as that of "At abnormal completion" in the following section.
Page 29 Response message format
Item list
End code
Sub command
Index
Sub Index
Reserved
Number of data value
L
H
L
H
L
H
L
H
20h
40h
01h
00h
Refer to the following for details.
End code
Index
Sub Index
Reserved
Number of data value
Read data
L
H
L
H
L
H
L or H (variable)
00h
00h
Refer to the following for details.
Item
Size
Endian
Description
Command
2 bytes
Little
4020h
Sub command
2 bytes
Little
0001h
Index
2 bytes
Little
Specify Index of the object. (
For the response message, the value specified in the request message is
stored.
Sub Index
1 byte
Little
Specify Sub Index of the object. (
For the response message, the value specified in the request message is
stored.
Reserved
1 byte
00h (fixed)
Number of data value
2 bytes
Little
Read data: 00h (fixed)
Read data
Variable
Little
The response data of the object is stored.