A liquid level detection system and liquid level detection method

Abstract

The invention discloses a liquid level detection system, comprising: a photoelectric acquisition module, a threshold value calculation module, a variance calculation module, a state judgment module and a liquid level time calculation module connected in sequence; Real-time acquisition; the threshold calculation module is used to store the high state threshold, the low state threshold, the maximum stable variance and the minimum stable variance; the described variance calculation module is used to calculate the variance of the real-time photoelectric value using the moving variance method; the described The state judging module is used to judge the state of the photoelectric value; the liquid level time calculation module is used to obtain the time when the liquid to be measured drops to the photoelectric collection module. The invention also discloses a liquid level detection method. The invention adopts the moving method to detect the arrival time of the liquid level, and can accurately detect the liquid level in different environments and for different liquids to be tested, and has strong anti-interference ability.

Description

technical field [0001] The invention relates to the technical field of detection, in particular to a liquid level detection system and a liquid level detection method. Background technique [0002] With the development of electronic technology, automatic instruments have gradually replaced manual labor to detect liquid levels. The traditional liquid level detection method usually simply sets a fixed threshold, and when the photoelectric value is greater than the threshold, it is judged that the liquid level has reached. The disadvantages of this judgment method are as follows: (1) The degree of transparency of the oil sample is different. When detecting a relatively transparent oil sample, the photoelectric value of the liquid when the light is blocked and the photoelectric value when the light is not blocked are both greater than the set threshold. Then the liquid level cannot be detected. (2) The kinematic viscosity needs to be measured at a constant temperature. When me...

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Problems solved by technology

The disadvantages of this judgment method are as follows: (1) The degree of transparency of the oil sample is different. When detecting a relatively transparent oil sample, the photoelectric value of the liquid when the light is blocked and the photoelectric value when the light is not blocked are both greater than the set threshold. can not detect liquid level

(2) The kinematic viscosity needs to be measured at a constant temperature. When measured at a high temperature (such as a constant temperature of 100°C), the photoelectric value will change as the temperature rises. When the minimum value of the photoelectric value exceeds the threshold, the liquid level cannot be detected.

(3) Light is reflected and refracted when the liquid level reaches the moment, and the photoelectric value may change back and forth. By simply setting a fixed threshold, the viscosity value is small, that is, the liquid level passes through the photoelectric quickly, and the influence is small, but the viscosity value is large. That is to say, when the liquid level slowly passes through the photocell, the influence is great, and the liquid level cannot be accurately captured, and the repeatability is poor

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