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Setup Guide: C6 IO EtherCAT Communication with a Beckhoff PLC

Colin Zauner | March 1st, 2022
Beckhoff CX5120 PLC wired up on a Din Rail mounted next to KEB EtherCAT IO modules
A Beckhoff CX5120 PLC is wired up to KEB EtherCAT IO modules on a Din rail to show communication compatibility.


This post shows how to set up an EtherCAT communication between a Beckhoff CX5120 Embedded PC and C6 EtherCAT I/O modules.

KEB’s line of EtherCAT I/O is scalable and is available in a wide range of options and configurations. EtherCAT allows for efficient and high-speed data transfer to meet the demands of high-performance machines. Each module is DIN rail mounted and easily snaps into each other. With a compact design and EtherCAT’s flexible topology, C6 EtherCAT I/O reduce wiring and installation cost.

In this example, the Beckhoff CX5120 embedded PC is connected to a BusCoupler + DI16/DO16 module, and 4 – channel Analog Output module.



#1 – Import KEB IO description files into TwinCAT

The EtherCAT description files of each KEB IO module must be imported into TwinCAT. The ESI file KebIoModules.xml includes all standard KEB I/O modules and can be downloaded from this link (click here to download) or exported from Combivis Studio 6. Copy the KebIoModules.xml file to the following directory: C:\TwinCAT\3.1\Config\Io\EtherCAT.


Screenshot showing the directory: C:\TwinCAT\3.1\Config\Io\EtherCAT

Next, restart TwinCAT and select TwinCAT -> Reload Devices.


Screenshot showing how to select TwinCAT to Reload Devices


#2 – Insert KEB EtherCAT IO modules into the project according to system configuration

It is now possible to set up the EtherCAT configuration according to the desired topology. First, add an EtherCAT master inside the TwinCAT project by right-clicking Add New Item under I/O devices. Insert the EtherCAT Master according to the Target controller type.


Screenshot showing how to Insert the EtherCAT Master according to the Target controller type


Next, insert a KEB Bus Coupler after the EtherCAT master. The Bus Coupler connects the EtherCAT master to EtherCAT slaves and provides the E-bus power supply to connected I/O modules. Right-click on the EtherCAT master and select insert device. The KEB IO modules imported from the KebIoModules.xml file can be found under KEB Automation KG.


Screenshot showing KEB IO modules imported from the KebIoModules.xml file.


Finally, add any additional I/O modules in the system according to the desired topology. Right-click on the previously added Bus Coupler and select insert device. Insert the desired I/O modules found under the KEB Automation KG group.


Screenshot showing how to add additional I/O modules in the system according to the desired topology.


#3 – Configure IO module settings

Each IO module includes EtherCAT slave settings preset from the device description. The default settings are generally sufficient for most EtherCAT configurations. To edit EtherCAT settings or link variables, select the desired I/O module to view the configuration options.


Screenshot showing how to edit EtherCAT settings


At this point, the KEB I/O configuration is complete. The PLC project can be compiled and downloaded into the PLC.

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