CU2508 Ethernet Port

A CU2508 Ethernet port must be added to the EtherCAT master before the modules are added.

CU2508 Ethernet Port 1:
Expand Solution Explorer > TwinCAT Project > I/O > Devices
Right-click on Device (EtherCAT) to open the context menu
Click Add New Item... in the context menu
CU2508 Ethernet Port 2:

The Insert Device dialog box opens.

Expand Beckhoff Automation GmbH & Co. KG > Ethernet Port Multiplier (CU25xx)
Select CU2508 Ethernet Port
If required, enter a name for the CU2508 Ethernet Port in the Name input field
Confirm with OK

A Box (CU2508) is added to the EtherCAT master.