Patent ID: 8593214

Claim:
A field device for process instrumentation, comprising: an interface for connecting a two-wire line, the interface including a series circuit having a transistor circuit by which a loop current of the interface is adjustable as a function of a control signal; an electrical power supply configured to produce operating energy for the field device based on the loop current and a voltage drop; a device configured to detect the loop current as an actual value; a regulator; a first feedback path, the actual value being passed through the first feedback path to the regulator for producing the control signal, and a nominal value corresponding to a measured value to be transmitted being supplied to the regulator for comparison with the actual value; a second feedback path, the actual value being passed through the second feedback path as a compensation signal for suppression of disturbances injected via the two-wire line to a summation point provided for production of an input signal for the transistor circuit as a function of the control signal and the compensation signal.