I'm not sure offhand if KUKA makes a ModBus option for the KRC4.
But for the PLC<>Robot connection, you need either EtherNet/IP or ModBus -- not both. Your screenshots were mixing incompatible protocols, which is creating confusion.
EDS files define devices, not scanners. So if you have created an EDS file for the PLC, this implies that you intend to use the robot as scanner, and the PLC as device. In this case, the EDS file for the PLC needs to be added to WorkVisual.
I'm sorry for make you confused. I'll correct that.
PLC is a slave, so I don't need to import any eds file to codesys?