Patent ID: 7079958

Claim:
A method of operating a process measuring device, especially an electromagnetic flowmeter having a measuring tube inserted in a line conducting a medium, especially a fluid medium, which method comprises the steps of: causing the fluid to flow through the measuring tube; causing an electrical, particularly bipolar, excitation current to flow through an operating circuit of the flowmeter to drive an excitation arrangement arranged on the measuring tube, and acting on the measuring tube and/or on the medium flowing therethrough; producing, by means of a sensor arrangement arranged on the measuring tube, at least one, electrical, measurement signal (u) corresponding to the physical, measured variable; digitizing the measurement signal (u) or at least a portion thereof to generate a digital sampling sequence (AF) representative of a waveform of the measurement signal (u); storing at least a part of the digital sampling sequence (AF) to generate a first data set (DS 1 ), which represents, instantaneously, a waveform of the measurement signal (u) within a predeterminable time interval; detecting an anomaly in the waveform of the measurement signal caused at least in part by an, especially pulse-shaped, interference potential (E 222 ) contained in the measurement signal, by detecting within the stored first data set (DS 1 ) a data group (DS A ) which digitally represents the anomaly; extracting the data belonging to the data group (DS A ) from the stored first data set to generate an interference-free second data set (DS 2 ); and determining, using the second data set (DS 2 ), a measured value (XM) representative of a physical variable of the flowing fluid.