Input device for a field instrument for process instrumentation as well as procedures for detecting a key operation of such an input device

摘要

Input device for a field device (1) for process instrumentationwith at least one key (5) 8) the magnetic field sensor (9... 12) is assigned to the generation of at least one key-dependent measuring signal (13) for each mode of operation. 16), andwith an evaluation device (4) on which the measurement signal is directed, for the detection of a key operation based on the measurement signal,marked by it,that an additional magnetic field sensor (17) is available to produce at least one key (5) in a different way from the respective mode of operation. 8) dependent further measurement signals (18), where the additional magnetic field sensor (17) is essentially exposed to the same interference fields as the magnetic field sensor (5...8) assigned to at least one key (9...12) and serves to compensate for the influence of magnetic interference fields on its measurement signal (13...16); andthat the analyser is trained to evaluate the additional measurement signal in addition to at least one key to eliminate interference in the detection of a control.