I never used these, but it seems it is based on some variables which you can read/write to control it.
To use this in combination with CoDeSys V3, you need to have a device which is EtherCAT master.
Then you need to install the .xml files in the device repository (menu Tools=>install device).
See http://www.beckhoff.com/english/downloa ... 6931806140
Download the zip file and install at least the "Beckhoff EL7xxx.xml"
After installing it you can add it to your EtherCAT I/O configuration and access the variables.