BECKHOFF EP9128 - Manual (Page 18)

Basic functioin principles
Reconnection
Once the connection has been restored, the EK1122 reports to the master that a link is present again at port
D (3). The EtherCAT master will then make its process data available again for this section. One the
preparations are complete, it will instruct the EK1122 to re­open port D (3) for regular data exchange. Cyclic
and acyclic data traffic with the other EtherCAT slaves continues normally.
Note
External access to EtherCAT diagnostics
The system offers a wide range of options for accessing status and diagnostic information
and EtherCAT master functions from the PLC. Almost all information displayed by the Sys­
tem Manager online can also be retrieved via ADS (see figures on this page). System Man­
ager functions can also be triggered via PLC or ADS. Please refer to the relevant sections
in the Beckhoff Information System and the notes on EtherCAT diagnostics.
3.2 Basic function principles
The EtherCAT star hub EP9128 is an infrastructure device without controllable input/output data (I/O). It can
be used
• as a junction point for conducted Fast Ethernet, in order to connect EtherCAT terminal stations, drives
or any other EtherCAT slaves to drop lines
• as distributed clocks reference clock (see EtherCAT System Documentation)
It has no I/O and no CoE directory and is not parameterizable. The core functions of the link control and
distributed clocks synchronization are mapped by the ESCs.
Structure
In order to provide 8 EtherCAT ports, the EP9128 has three internal communication ICs (ESCs), which are
connected in series internally. For this reason the EP9128 appears as three individual slaves in the
EtherCAT configurator, although they are located in one housing. The interrelationship between the internal
ESC ports (A, B, C, D) and the descriptions of the connection sockets (1 to 8) is as follows:
Fig. 13: EP9128 diagram
EP9128 18 Version 2.1.0