Partially filled pipe detection circuit of electromagnetic flowmeter

Abstract

The invention provides a partially filled pipe detection circuit of an electromagnetic flowmeter. The partially filled pipe detection circuit comprises a CPU drive signal waveform transforming circuit, a first-grade passive lowpass filtering circuit, a differential signal amplification circuit, an active power filter circuit, and an absolute value transforming circuit. One end of the CPU drive signal waveform transforming circuit acquires high-frequency pulse signals, and the other end is connected with the first-grade passive lowpass filtering circuit. The first-grade passive lowpass filtering circuit is connected with the differential signal amplification circuit. A voltage follower circuit in the active power filter circuit is connected with a second-order active high-pass filtering circuit. The differential amplification circuit is also connected with the voltage follower circuit. The second-order active high-pass filtering circuit is connected with the absolute value transforming circuit. The absolute value transforming circuit outputs detection signals. A [pi] type filter circuit formed by a RC is used in the input end of a differential operational amplifier, and the [pi] type filter circuit can effectively filter spike noise caused by liquid flow when pipes are partially filled, so as to reduce interference. The partially filled pipe detection circuit is advantaged by real-time online monitoring, fast response speed, relatively good noise inhibiting ability, stable and reliable detection performance.

Description

technical field [0001] The invention relates to a detection circuit, in particular to a non-full pipe detection circuit of an electromagnetic flowmeter. Background technique [0002] At present, the existing circuit superimposes the detection signal on the circuit path of the flow measurement signal, uses an analog switch to switch the selection in time, and sends an excitation signal with a pulse width every 20S, so the dynamic response is very slow. When the full pipe state changes to the non-full pipe state, the detection response speed is very slow, the partial pipe detection is unstable, and the reliability of the partial pipe detection is very low. When the electromagnetic flowmeter is not full, the medium in the pipe cannot completely fill the pipe , so there is a part of the air inside, when the liquid in the pipeline flows, the spike noise in the pipeline will be very loud, and the spike signal may submerge the detection signal. The measurement condition of the ele...

AI Technical Summary

Problems solved by technology

[0003] In order to solve the above technical problems, the object of the present invention is to provide a part-full pipe detection circuit of an electromagnetic flowmeter to solve the existing defects of slow response speed, unstable part-full pipe detection, and low reliability.

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