Siemens MICROMASTER 420 Operating Instructions Manual page 42

Data transfer using CANopen
Using two examples, the following two sections show the read and write access
operations using SDO on two PKW objects.
Example 1: Reading parameter r0964.02
Parameter number (964) must be converted into a hexadecimal number in order to
read the value of parameter r0964.02:
964dec = 3C4H.
After this, 2000H must be added:
03C4H + 2000H = 23C4H.
The numerical sequence after the point in the specification of the PKW object (in
this case: 2 in r0964.02) corresponds to the subindex number of the CANopen
object. This must be converted from a decimal number into a hexadecimal number:
02 dec =2H
Now, an SDO read task is defined for the object that was determined:
• Byte 0
− Bit 5 - 7 (CCS)
− Bit 0 - 4
• Byte 1
− Bit 0 - 7
• Byte 2
− Bit 0 - 7
• Byte 3
− Bit 0 - 7
• Byte 4-7
− Bit 0 - 7
CANopen telegram of the master:
Table 3-7
Byte 0:
Bits 7-5
CCS = 2
CANopen MICROMASTER response telegram
Table 3-8 MICROMASTER response to the SDO read request
Byte 0:
Bits 7-5 Bit 4 = 0 Bits 3,2
SCS = 2 n= 2 (word)
(initiate (number of
upload bytes that do
respons not contain
e) any data)
42
= 2H ->initiate upload request
= 0H ->always for initiate SDO-upload request
= C4H ->index of the object, part 2
= 23H ->index of the object, part 1
= 02H ->subindex of the object
= 00H ->always for initiate SDO-upload request
SDO read request to parameter r0964.02 (object 0x23C4* sub2)
Bytes 1
Bit 4-0 = 0 C4H
e = 1 s = 1
expedi (data
ted size is
transfe indicat
r) ed)
Byte 2 Byte 3
23H 02H
Bytes 1,2 Byte 3
23C4H 02H
(index) (subindex)
CANopen Option Module
Issue 01/05
Bytes 4,5 Bytes 6,7
reserved = 0
Bytes 4,5 Bytes 6,7
Word data 0H
(2 bytes (two bytes,
data) no data as
specified in
n)
Operating Instructions
6SE6400-5BC00-0BP0