Solution conductivity measurement method for excitation of triangular wave and integrating treatment of response current

Abstract

The invention discloses a solution conductivity measurement method for the excitation of a triangular wave and the integrating treatment of response current. A voltage signal of an alternating-current symmetrical triangular wave with the amplitude of U and the period of 2T is adopted to excite an electrode, the wave trough (or the wave peak) of the triangular wave is used as an origination moment, the 3 time quartering division point moments of the upper wave band (or the lower wave band) of the triangular wave are respectively used as destination moments for integrating the response current of the electrode, three current integral values are respectively set as q1, q2 and q3, the resistance value Rx of a solution is calculated by utilizing the following formula Rx=TU|2q1-q2|(3q2-3q1-q3)<2> / 4[(2q1-q2)<4>+(2q2-q1-q3)<4>]ln<2>|(2q1-q2) / (2q2-q1-q3)|, then the conductivity is obtained by using a formula of G=K / Rx, and the K is the constant of the electrode. According to the scheme, the influence of distributed capacitance and the polarized capacitance of the electrode on measurement is completely eliminated, no special requirement to the magnitude of the frequency of an excitation signal exists, the magnitude of the frequency of the excitation signal can be randomly selected within a wider range, the measurement requirements of low conductivity and high conductivity can be met, and the aim of integrating the response current of the electrode is to avoid the defect that the current detection at an independent point moment is easily interfered.

Description

technical field [0001] The invention relates to a method for measuring the conductivity or resistivity of a solution, in particular to a method that uses a triangular wave as an excitation signal and preprocesses the integral of the response current to improve the anti-interference performance of the measurement, which can eliminate the electric double layer capacitance of the electrode and the electrode distributed capacitance on the conductivity of the solution. Or the measurement method of resistivity measurement influence. Background technique [0002] The basic measurement method of solution conductivity is to measure the voltage U applied across the electrodes placed in the solution. D and the current I flowing through the electrodes, calculate the resistance R=U between the electrodes D / I, use G=K / R to calculate the conductivity of the solution, where K is the electrode constant. However, the electrode placed in the solution will be polarized after being energized,...

AI Technical Summary

Problems solved by technology

Commonly used methods include phase-sensitive detection method, double-pulse method, and dynamic pulse method. All methods are finally converted to decoupling the resistance-capacitance network of the conductivity cell model. Some calculation methods require iterative processing to increase the amount of calculation and affect real-time Processing or affecting calculation accuracy

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