Ethernet uses the standerd IEEE 802.3 protocal through which u can communicate with all Window based appllication, pc and all other application which are follwoing this standerd.But Control net is quit a lot properitery network based on the control system (
DCS or PLC) like Foxboro,Centum,Experion etc. Device net is again a universal accepted protocal that is exclusively used for communication between field device with control system (A dedicated I/O card (Modem) required like prfibus,fielbus card).