DSP-based Electromagnetic Flowmeter with Sinusoidal Excitation

The paper presented a DSP-based electromagnetic flowmeter. There are 4 pairs of electrodes and a pressure sensor for effective flowrate measurement in partially filled pipes. Although this setup is able to measure different flow profiles, our development focused on the improvement of measurement accuracy by signal processing methods. A sinusoidal excitation is used allowing fast sampling of the flowrate. The coils are driven by class-D amplifiers minimizing the power consumption of the module. The demodulation of the electrode voltage is carried out by a linear phase Hilbert transformer. Linear phase filters guarantee that the flowrate waveform is preserved. Resonator-based controller ensures the automatic and effective suppression of disturbing electrode voltages. Measurement results clearly confirmed the expectations: tests in filled mode have shown high accuracy and reliability. Our ongoing task is testing the flowmeter in partially filled mode, while new developments can aim the exploitation of the electrode pairs for flow profile measurement