EtherCAT Cable Redundancy

TwinCAT uses a second adapter to realize EtherCAT Cable Redundancy. The EtherCAT frames are sent by both ethernet adapters simultaneously. The second adpater must be connected to a free ethernet port of an EtherCAT slave. Now the EtherCAT frames from the first EtherCAT adapter pass all EtherCAT slaves and arrive at the second adapter. The EtherCAT frames from the second adapter travel in the oposite direction. In case of a single cable fault on the path between the first EtherCAT adapter and the second adapter, all EtherCAT slaves are still accessible.

Configuring Cable Redundancy

Following steps show how to configure redundancy with the System Manager:

  1. Disconnect second adapter
  2. Right click on the EtherCAT device in the tree view of the System Manager and select the entry "Scan Boxes.." in the context menu of the device.
  3. Open the "EtherCAT" tab of the EtherCAT device and press the "Advanced Settings…" button to open the "Advanced Settings" dialog.
  4. In the "Advanced Settings dialog" you have to select "Redundancy/Mode" in the tree view on the left side:
    EtherCAT Cable Redundancy 1:
  5. Select the "Second Adapter" radio button and press the "Search…" button to select the ethernet adapter.
  6. Next you must select the redundancy port at the bottom. This is the ethernet port of an EtherCAT slave the second adapter is connected to. With some topologies it is possible to choose between more than one port. It is important that the ethernet device is connected to exactly this port. Otherwise the redundancy will not operate correctly.
    Example:
    EtherCAT Cable Redundancy 2:
    The above configuration has following topology:
    EtherCAT Cable Redundancy 3:
    The redundancy adapter can now be connected to either the free port of Term 2(EK1100):
    EtherCAT Cable Redundancy 4:
    or to the free port of Term 6(EK1100):
    EtherCAT Cable Redundancy 5:
    or to the free port of Term 8(EK1110) :
    EtherCAT Cable Redundancy 6:
    The blue line indicates the redundancy path. Along this path a single cable loss is possible without loss of communication to an EtherCAT slave.
  7. Connect the second adapter to ethernet port configured under 6.
  8. Activate the configuration or reload the devices in Config Mode to activate the redundancy mode.