ifm
System Manual
ecomat
mobile
PDM360NG (CR1080, CR1081, CR9042) Target V01
2011-07-28
Annex
CANopen tables
422
13.4.2
Structure of CANopen messages
Structure of the COB ID ............................................................................................................ 422
Function code / Predefined Connectionset ............................................................................... 423
SDO command bytes ................................................................................................................ 424
SDO abort code......................................................................................................................... 425
9971
A CANopen message consists of the COB ID and up to 8-byte data:
COB ID
DLC
Byte 1
Byte 2
Byte 3
Byte 4
Byte 5
Byte 6
Byte 7
Byte 8
X X X X X X X X X X X X X X X X X X X X
Details are given in the following chapters.
NOTE:
Please note the reversed byte order!
Examples:
Value [hex]
Data type
Byte 1
Byte 2
Byte 3
Byte 4
Byte 5
Byte 6
Byte 7
Byte 8
12
BYTE 1 2 – – – – – – – – – – – – – –
1234 WORD 3 4 1 2 – – – – – – – – – – – –
12345678 DWORD 7 8 5 6 3 4 1 2 – – – – – – – –
Structure of the COB ID
9972
The first part of a message is the COB ID. Structure of the 11-bit COB ID:
Nibble 0
Nibble 1
Nibble 2
11
10 9 8 7 6 5 4 3 2 1 0
--
3
2
1
0
6
5
4
3
2
1
0
--
function code
node ID
The COB ID consists of the
function code
(
→
page
) and the node ID.
Example:
Communication object = TPDO1 (TX)
Node number of the device = 20
16
= 32
10
Calculation:
Function code for the communication object TPDO1 = 3
16
Significance of the function code in the 11-bit COB ID = 3
16
x 80
16
= 180
16
Add the node number (20
16
)
the COB ID is: 1A0
16
1
A
0
3
2 1 0 3 2 1 0 3 2 1 0
0
0
0
1
1
0
1
0
0
0
0
0
--
3
16
= 3
10
20
16
= 32
10
