https://download.beckhoff.com/download/Config/EtherCAT/XML_Device_Description/Beckhoff_EtherCAT_XML.zip（含在EL6xxx里面）
https://download.beckhoff.com/download/configuration-files/io/ethercat/xml-device-description/Beckhoff_EtherCAT_ESI_EL6070-1xxx.zip（针对EL6070-1xxx）
