Fieldbus is an all-digital, serial, two-way multi-drop communication link between intelligent field devices. It serves as a local area network for process control, remote input-output, and high-speed industrial automation applications. As fieldbus involves digital communication, integration of total plant automation is possible by proper planning. Fieldbus technology reduces wiring to the extent of 80 percent compared to the conventional one (which involves one-to-one wiring scheme) resulting in reduced cost and time for installation. Foundation Fieldbus is a fieldbus technology developed by Fieldbus Foundation, a non-profit-making consortium that recommends and develops the technical specifications for Foundation Fieldbus. Foundation Fieldbus signals are encoded in Manchester coded biphase-L technique. PROcessFIeldBUS (PROFIBUS) is an open fieldbus standard which can be applied to both process automation and factory manufacturing automation. PROFIBUS supports two types of field devices: a master device and a slave device, respectively, called ‘master’ and ‘slave’ stations.