FC510x - PCI Cards for CANopen

Identifier distribution

 

Default identifier

CANopen provides default identifiers for the most important communication objects, and these are derived from the 7-bit node address (the node ID) and a 4-bit function code in accordance with the following scheme:

 defaultidentifier
Structure of the default identifier

For broadcast objects the node ID is set to 0. This gives rise to the following default identifiers:

 
 

Broadcast objects

 
Object
Function
Function code
resulting COB ID hex / dec
Object for comm. Parameter / mapping
NMT
Boot-Up
0
0x00 / 0
- / -
SYNC
Synchronization
1
0x80 / 128
0x1005 + 0x1006 / -
 
 

Peer-to-peer objects

 
Object
Function with I/O devices
Function code
resulting COB ID hex / dec
Object for comm. Parameter / mapping
Emergency
Status / error
1
0x81 - 0xFF/ 129 - 255
- / -
PDO1 (tx)
dig. inputs
11
0x181 - 0x1FF / 385 - 511
0x1800 / 0x1A00
PDO1 (rx)
digital outputs
100
0x201 - 0x27F/ 513-639
0x1400 / 0x1600
PDO2 (tx)
analog inputs
101
0x281 - 0x2FF/ 641-767
0x1801 / 0x1A01
PDO2 (rx)
analog outputs
110
0x301 - 0x37F/ 769-895
0x1401 / 0x1601
PDO3 (tx)
analog inputs*
111 
0x381 - 0x3FF / 897 - 1023
0x1802 / 0x1A02
PDO3 (rx)
analog outputs*
1000 
0x401 - 0x47F/ 1025 - 1151
0x1402 / 0x1602
PDO4 (tx)
analog inputs*
1001 
0x481 - 0x4FF/ 1153 - 1279
0x1803 / 0x1A03
PDO4 (rx)
analog outputs*
1010
0x501 - 0x57F/ 1281 - 1407
0x1403 / 0x1603
SDO (tx)
Parameter
1011
0x581 - 0x5FF/ 1409-1535
- / -
SDO (rx)
Parameter
1100
0x601 - 0x67F/ 1537-1663
- / -
Guarding
Life/node guarding,
Heartbeat,
Boot-up message
1110
0x701 - 0x77F/ 1793-1919
(0x100C, 0x100D, 0x100E, 0x1016, 0x1017)

* For historical reasons, the Beckhoff default mapping applies to PDOs 3 and 4 in Beckhoff I/O devices. In most configurations, PDOs 3+4 contain data related to analog inputs and outputs, but there can also be "excess" data from digital I/Os, or data from special terminals. Details may be found in the Bus Coupler documentation.

Up until version 3 of the CANopen specification, default identifiers were assigned to 2 PDOs at a time. The Beckhoff Bus Couplers up to firmware status BA correspond to this issue of the specification. After firmware version C0 (CANopen version 4), default identifiers are provided for up to 4 PDOs.