Capacitive liquid level detection device, method and system

Abstract

The invention discloses a capacitive liquid level detection device, method and system. The device includes: a liquid suction probe, which is used to absorb the liquid to be measured and output its own capacitance; an A / D conversion unit, which is used to sample the liquid suction The capacitance value output by the probe is converted into a corresponding digital voltage signal and output; the judging unit is used to judge whether the voltage value of the digital voltage signal sampled this time output by the A / D conversion unit is less than or equal to The voltage value of the digital voltage signal sampled last time, when the judgment result is yes, the output voltage difference; and the comparison unit, used to compare the size of the voltage difference with a predetermined threshold, if the voltage difference is greater than the If the predetermined threshold is reached, a control signal for controlling the liquid suction probe to stop moving is output. The invention simplifies the existing liquid level detection steps, improves the accuracy of liquid level detection, and has good adaptability and stability.

Description

technical field [0001] The invention relates to the field of liquid level detection, in particular to a capacitive liquid level detection device, method and system. Background technique [0002] At present, in order to obtain the clinical diagnosis information of patients more accurately, more and more biochemical analysis instruments are used. Existing biochemical analysis instruments usually use the capacitive liquid level sensing method for liquid level detection, which has the characteristics of sensitive response and high stability. [0003] A method for detecting the liquid level and judging whether it is successful or not is proposed in the prior art: the probe liquid level detection device includes: a liquid suction probe, which is used to absorb the liquid to be tested and output its own capacitance; a conversion module, which is used to receive the suction The capacitance value output by the liquid probe, and output the analog voltage signal corresponding to the c...

AI Technical Summary

Problems solved by technology

[0004] In the prior art, it is necessary to detect that the voltage value of the current voltage signal is greater than the low threshold value before starting to calculate the slope of the adjacent voltage signal. However, due to the individual differences of the instrument and the influence of the distributed capacitance of the surrounding environment, the threshold value of each instrument is different. When detecting, it is necessary to recalibrate the corresponding detection threshold according to different instruments and different environments, which will cause disadvantages such as cumbersome debugging and complicated steps.

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