A capacitive liquid level measuring device

Abstract

The invention relates to a capacitor liquid level measuring device. Liquid level signals acquired by a capacitor reflect changes of measured liquid level via a consumed energy of capacitance reactance. Signal sources are transmitted to a power driving circuit via a fixed frequency signal, signals are input to a measuring capacitor by power driving; and meanwhile, and power signals are converted into current signals by a power-current converting circuit and then outputted. A sensor circuit formed by the capacitor has the advantages of few in elements, simple circuit structure, good stability, high measuring accuracy, flexible circuit reflection and the like, is applicable to capacitor probes in different types to measure liquid level directly, and has the measuring accuracy better than 0.1%. Due to the current-type parameter output, the capacitor liquid level measuring device is easy in remote measurement, digital displaying and automatic controlling, and is suitable for being used in liquid level measuring sensor circuits.

Description

technical field [0001] The invention provides a liquid level measurement sensor circuit in engineering applications, specifically a capacitance liquid level measurement device. Background technique [0002] At present, there are many methods for liquid level measurement in engineering, and the commonly used methods are float type, pressure method, nuclear radiation method, light guide method, ultrasonic method, microwave method, radar method, capacitance and radio frequency admittance method for liquid level detection. . When environmental conditions, mechanical components, long transmission distances, and automation level issues are affected, these detection methods are susceptible to interference, resulting in inaccurate detected liquid level information and misjudgment. [0003] The capacitive liquid level sensor has the advantages of simple probe structure, good dynamic response, high sensitivity, strong resolution, no moving parts, not easy to damage, long service life...

AI Technical Summary

Problems solved by technology

But the current capacitive probe has disadvantages: first, due to the structural characteristics of the probe itself, its output impedance is high, its load capacity is poor, and it is susceptible to external interference; The parasitic capacitance formed by the surrounding conductors is large, which makes it difficult to convert accurate capacitance signals

However, these designs are improvements for a specific need, so the design circuit structure is complex, and there are different requirements for the structure of the capacitance probe.

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