Some questions arise when we decide to implement a new control system or revamp our process automation using the state of the art technology. What to do with my old equipment, which is still in good shape? Can I integrate a new system with my old control system, reducing the initial investment? These issues were an initial preoccupation of leading Foundation Fieldbus developers and consequently many solutions are available now. All these make the migration path to Fieldbus as smooth as a user wishes. In this paper we will discuss several ways of interconnecting Foundation Fieldbus to other automation equipment, arguing its benefits and disadvantages. Starting from the connection to conventional pneumatic and electronic instruments and valves, passing through Hart signaling and reaching the connectivity to PLC (Programmable Logic Controller) and DCS (Distributed Control System).
