BECKHOFF EL7037 - Manual (Page 67)

Commissioning
Fig. 58: Selecting the EtherCAT connection (TwinCAT 2.11)
Fig. 59: Selecting the EtherCAT connection (TwinCAT 2.11 R2)
Then assign a real Ethernet port to this virtual device in the runtime system.
Fig. 60: Selecting the Ethernet port
This query may appear automatically when the EtherCAT device is created, or the assignment can be set/
modified later in the properties dialog (see Fig. “EtherCAT properties dialog”).
EL70x7 67 Version 1.0