PDO Linking in CANopen

Question

In the CANopen Network, all devices (clients, formally "slaves") communicate with a central controller (master). Therefore, no slaves listen to the process data objects (PDOs) and therefore to the CAN identifiers of another slave. Using PDO Linking, PDOs can be exchanged directly without a master. Therefore, the CAN identifiers have to be adjusted accordingly.

Even if there are many sources concerning PDO Linking on the internet, I did not find any specific examples (e.g. schematic linking of 2 client devices). Can you recommend any resources for PDO Linking (book, articles, websites, ...)?

Sources: Beckhoff Information System

Answer 1

The topic of PDO linking is discussed in a couple of websites, however only at a very abstract level. Useful resources for understanding the theory are:

• CANopen Solutions: PDO services

• Micro Control: Identifier Usage in CANopen Networks

• embedded-communication: CANopen PDO Linking (German)

• Beckhoff Information System: Process Data Objects (PDO)

• Emotas: Process DataLinker

• Vogel: Optimierung der PDO-Kommunikation in CANopen-Netzwerken (German)

I would be thankful for your recommendations concerning hands-on examples!

Answer 2

Just looking at your source: you need to adapt TPDO of Device 1 and RPDO of Device 2 accordingly. You should be sure that COB-ID of TPDO shall be same as COB-ID of RPDO. You should also be sure that you map the data properly. In such a case Device 2 will be able to receive data directly from Device 1