3
CANopen access procedure
22
Festo – GDCP-CMMP-M3/-M0-C-CO-EN – 1510b – English
3.2.1
SDO Sequences for Reading and Writing
To read out or describe objects of these number types, the following listed sequences are used. The
commands for writing a value into the motor controller begin with a different identifier, depending on
the data type. The answer identifier, in contrast, is always the same. Read commands always start with
the same identifier, and the motor controller answers differently, depending on the data type returned.
All numbers are kept in hexadecimal form.
Identifier
8 bits
16 bit
32 bit
Task identifier
2F
h
2B
h
23
h
Response identifier
4F
h
4B
h
43
h
Response identifier in case of
error
–
–
80
h
Tab. 3.3
SDO – response/task identifier
EXAMPLE
UINT8/INT8
Reading of Obj. 6061_00
h
Return data: 01
h
Writing of Obj. 1401_02
h
Data: EF
h
Command
40
h
61
h
60
h
00
h
2F
h
01
h
14
h
02
h
EF
h
Response:
4F
h
61
h
60
h
00
h
01
h
60
h
01
h
14
h
02
h
UINT16/INT16
Reading of Obj. 6041_00
h
Return data: 1234
h
Writing of Obj. 6040_00
h
Data: 03E8
h
Command
40
h
41
h
60
h
00
h
2B
h
40
h
60
h
00
h
E8
h
03
h
Response:
4Bh 41
h
60
h
00
h
34
h
12
h
60
h
40
h
60
h
00
h
UINT32/INT32
Reading of Obj. 6093_01
h
Return data: 12345678
h
Writing of Obj. 6093_01
h
Data: 12345678
h
Command
40
h
93
h
60
h
01
h
23
h
93
h
60
h
01
h
78
h
56
h
34
h
12
h
Response:
43
h
93
h
60
h
01
h
78
h
56
h
34
h
12
h
60
h
93
h
60
h
01
h
Caution
The acknowledgement from the motor controller must always be waited for!
Only when the motor controller has acknowledged the request may additional requests
be sent.
