What happens?
It is not possible to establish a communication between controller and EtherCAT nodes.
The EtherCAT nodes are marked by a red triangle symbol in the PLC Designer.
The following error is indicated in the 'Diagnostics Master' tab of the EtherCAT Master or in 'EtherCAT Log Messages': EtherCAT_Master: Start master failed. Bus mismatch
When does the problem occur?
The 'Optional' setting is not supported with EtherCAT nodes, i.e. even if an EtherCAT node is marked as optional it has to be physically available at the EtherCAT bus.
Which products are affected?
PLC Designer from V3.0
Possible diagnostics?
Check in the 'Diagnostics Master' tab of the EtherCAT Master or in the EtherCAT Log Messages if the following error has occurred: EtherCAT_Master: Start master failed. Bus mismatch
Check if the 'Optional' checkbox is ticked in the 'Slave' tab of the EtherCAT node.
Short-term measurements/recommendations?
Deactivate the 'Optional' checkbox 'Optional' with all EtherCAT nodes.
Evaluation:
All nodes connected to the EtherCAT master in the PLC project must be available at the EtherCAT bus. The 'Optional' settting is not supported.
