Pre-defined connection set
The CANopen FD system designer is responsible that the used CAN-IDs are assigned uniquely to the CANopen FD devices. In order to simplify this task, CANopen specifies a pre-defined connection set. This is a set of default CAN-IDs assigned to the provided CANopen FD application layer protocols. Therefore, the default CAN-IDs have a 4-bit function code and the 7-bit node-ID.
|Message||Function code||Resulting CAN-ID
(depending on assigned node-ID)
|Index/sub-index of COB-ID parameter|
|NMT||00002||00016 (0)||Not configurable|
|SYNC||00012||08016 (128)||1005 0016|
|EMCY||00012||08116 (129) to 0FF16 (255)||1014 0016|
|TIME||00102||10016 (256)||1012 0016|
|TPDO_1||00112||18116 (385) to 1FF16 (511)||1800 0116|
|RPDO_1||01002||20116 (513) to 27F16 (639)||1400 0116|
|TPDO_2||01012||28116 (641) to 2FF16 (767)||1801 0116|
|RPDO_2||01102||30116 (769) to 37F16 (895)||1401 0116|
|TPDO_3||01112||38116 (897) to 3FF16 (1023)||1802 0116|
|RPDO_3||10002||40116 (1025) to 47F16 (1151)||1402 0116|
|TPDO_4||10012||48116 (1153) to 4FF16 (1279)||1803 0116|
|RPDO_4||10012||50116 (1281) to 57F16 (1407)||1403 0116|
|TSDO_1 a||10112||58116 (1409) to 5FF16 (1535)||Not configurable|
|RSDO_1 b||11002||60116 (1537) to 57F16 (1663)||Not configurable|
|Boot-up/Heartbeat||11102||70116 (1793) to 77F16 (1919)||Not configurable|
a default server SDO message (server-to-client);
b default server SDO message (client-to-server)
The CAN-IDs for the NMT message, the USDO client and USDO server messages, and the Heartbeat message are not configurable. This is to avoid loosing nodes. All other CAN-IDs are matter of configuration, in particular those of the PDOs. The configuration is done by means of the COB-ID parameters in the related object dictionary entries. COB-ID parameters are 32-bit values. The Bit 29 indicates, if 11-bit (default) or 29-bit CAN-IDs are used. The Bit 31 and Bit 30 are used protocol-specific.
Of course, the node-ID still needs to be assigned uniquely by the system designer. There are different options, how to set the node-ID. Common are DIP switch, local I/O, and the Layer Setting Services as defined in CiA 1305 (under development). Alternatively, geographical addressing by means of connectors with additional pins can be used to assign a node-ID (e.g. pre-installed wiring harnesses).
The CANopen FD pre-defined connection set guarantees that no CAN-ID is assigned to two nodes, if the node-IDs are distributed uniquely. The TIME publisher, and SYNC publisher do not need to be implemented in one entity, they could be in different nodes. The corresponding EMCY consumers and RPDOs can be configured in multiple nodes. The RPDOs corresponding TPDOs shall be provided by just one entity, which could be in different CANopen FD devices.
Each CANopen FD device implements an USDO client as well as USDO servers for all other CANopen FD devices in the network. This means, a full-meshed USDO communication is pre-defined.