High-precision Electromagnetic Flowmeter with Empty Pipe Detection via Complex Programmable Logic Device-based Waveform Recognition

Traditional electromagnetic flowmeters are inherently prone to external interference and uneven velocity distribution during measurement, which severely limits their accuracy. In this study, an improved method is proposed, which optimizes the excitation drive waveform, performs multiple filtering and amplification of the electrode input, and uses a Complex Programmable Logic Device to achieve rapid switching between positive and negative induction signals. This enables smooth rectification and, in combination with software filtering techniques, achieves highly precise performance. Additionally, empty pipe detection is realized by recognizing excitation waveform and input waveform patterns. Experimental verification shows that the designed electromagnetic flowmeter achieves an accuracy of 0.1% within a flow velocity range of 0.1-15 m/s, with system repeatability errors of less than 1%. The results validate the effectiveness of the proposed method in high-precision flow measurement. The study demonstrates that high-precision detection can be achieved with minimal additional cost, which is important for industry applications.