Beckhoff CU2508 - Fig. 16 Use of the CU2508 as an Ethercat Cable Redundancy Star Point; Fig. 17 Use of the CU2508 as an Ethernet Multi-Protocol Handler with Ethercat and TCP;IP

Product overview
Real-time Ethernet port multiplier 21
Version: 2.6
Fig.16: Use of the CU2508 as an EtherCAT cable redundancy star point
• EtherCAT cable redundancy with Distributed Clocks [
}37]
The common time base of the CU2508 ensures that EtherCAT slaves that require Distributed Clocks
are still subject to synchronization in the case of redundancy.
• Use of TCP/IP without real-time [
}40]
A downlink port on the CU2508 can be configured as a non-real-time Ethernet port, or the CU2508
works in the Ethernet over EtherCAT (EoE) network and forwards TCP/IP frames from the connected
EtherCAT systems.
Fig.17: Use of the CU2508 as an Ethernet multi-protocol handler with EtherCAT and TCP/IP
• Real time fieldbus on non-real-time controller
If an Ethernet-based fieldbus requires a reliable constancy with respect to the sending of
communication telegrams, low jitter is demanded in the cyclic operations of the controller. If a high-
performance controller is able to process the cyclic operations with sufficient frequency (= demanded
short cycle time), but the jitter, i.e. the regular interval between the cycles is inadmissibly high, then the
CU2508 system, as a real-time frame handler, can provide the constant interval in frame sending,
provided the new data are available early enough in the CU2508.