The process expensive sensors with an externally accessible common ground and method for the manufacture of a process expensive transmitter

摘要

Disclosed is a process control transmitter having an externally accessible DC circuit common that eliminates the need to perform level shifting of signals communicated between the transmitter and external processing electronics. The process control transmitter includes first, second and third terminals which feedthrough a housing. Circuitry contained in the housing is coupled to the first, second and third terminals and is adapted to communicate information to external processing electronics through the second and third terminals using a digital signal that is regulated relative to a DC common that is coupled to the second terminal. External processing electronics can couple to the second and third terminals and interpret the digital signal without having to perform level-shifting adjustments.