Circuit arrangement for the power supply of a two-wire sensor

A two-wire sensor ( 6 ) is attached to one pole of a voltage distribution source (U) by an initial connecting line (V 1 ) in which a current-limiting resistor (R 1 ) is positioned and is attached to the other pole by a second connecting line (V 2 ). Parallel to the series connection consisting of the two-wire sensor (S) and the current-limiting resistor (R 1 ) is at least one limiting diode (D 1 ). A current regulator (SR) which is attached to the poles of the power source (U) regulates a parallel current (I) which runs parallel to the current through the two-wire sensor (D), so that there is a sum current at the poles of the power source (U) that always corresponds to the measured value delivered by the two-wire sensor (S). The regulating inputs of the current regulator (SR) are connected to the terminals of a current-sensing resistor (R 2 ) positioned in a connecting line (V 1 ). When a HART®-interface is used with the two-wire sensor (S) a HART®-resistor (RH) is positioned in one of the two connecting lines (V 1 ).