This specification discloses an intelligent and digitalized process level interface which is referred to herein as an Intelligent Process Interface (IPI). The input of the IPI includes both analog and digital channels and therefore the IPI can be used for substations in transition or retrofit stages with both conventional and non-conventional primary devices. The IPI acts not only as a digitalized interface, but also as an intelligent supervisory and control unit for switching functions. The architecture of the IPI is flexible and allows for the functionality to be distributed to several devices.