Product Description:

The CU1128-0000 is an eight-port EtherCAT branching module produced by Beckhoff within the CU EtherCAT Junctions series. As an in-cabinet junction, it splits one EtherCAT line into multiple independent segments, enabling star, tree, or ring wiring topologies in distributed control systems. The device expands network architecture without adding active switching intelligence, and it passes telegrams transparently so real-time performance is preserved across connected machine segments.

In normal operation, the module uses an 8 x RJ45 interface arrangement that accepts standard Ethernet patch cables. Data exchange proceeds at 100 Mbit/s, the fixed line rate used by the EtherCAT protocol, so cycle times remain deterministic as downstream devices are added. Support for Distributed Clocks lets the junction forward timing information with sub-microsecond skew, which benefits synchronized motion axes and high-speed data acquisition. The electronics draw power from a 24 VDC supply, and because only the embedded EtherCAT Slave Controllers are energized, heat dissipation remains minimal. Each branch may extend up to 100 m, matching the maximum copper segment length for Fast Ethernet and providing generous reach between remote panels.

The compact housing snaps onto a DIN rail that is 35 mm wide, allowing convenient placement beside terminal blocks and power supplies. Incoming power is connected through a 3-Pole Spring Terminal, which provides tool-free, vibration-resistant retention of the 24 V leads. With a protection rating of IP20, the junction is suited for closed electrical enclosures where dust and liquid ingress are controlled. All eight channels carry frames that conform to EtherCAT, while the three internal ESCs automatically establish link redundancy and cut-through forwarding. The transmission medium is standard EtherCAT-qualified twisted-pair cable, and the installation position can be horizontal, vertical, or flat without affecting electromagnetic performance.