A seawater salinity measurement system and method based on quadrature lock-in amplification technology

Abstract

The invention discloses a system and method for measuring seawater salinity based on orthogonal phase-locked amplification technology. The system includes a constant temperature water tank, in which a conductivity cell, a spiral coil, an agitator and a constant temperature device are arranged, the conductivity cell, the agitator and the constant temperature device are connected with the detection control device, the detection control device is also connected with a multi-way valve, a peristaltic pump and a computer terminal. Tanks and standard seawater storage tanks, the outlet is connected to the inlet of the conductivity cell through a peristaltic pump and a spiral coil; two current electrodes and two voltage electrodes are set in the conductivity cell, and the current electrode is a composite oxide electrode loaded with nano-scale platinum; the voltage electrode It is a silver / silver chloride reference electrode; the detection control device adopts digital orthogonal lock-in amplification technology, and the lock-in module is realized by FPGA through digital programming. The method disclosed by the invention is convenient and quick to operate, has high testing efficiency and has relatively high performance index.

Description

technical field [0001] The invention relates to a seawater parameter measurement method, in particular to a seawater salinity measurement system and method based on orthogonal phase-locked amplification technology. Background technique [0002] Salinity is one of the most important physical and chemical characteristics of seawater, and its distribution change is an important factor that affects and restricts the distribution and change of other hydrological elements. come higher. The definition and method of measuring salinity has evolved several times since the nineteenth century. In 1980, after the Joint Panel of Experts on Oceanographic Common Tables and Standards (JPOTS) formally proposed and recommended the PSS-78 (The Practical SalinityScale 1978) practical salinity scale, the definition, measurement technology and measurement standard of salinity were unified into the conductivity method. Techniques for measuring salinity. [0003] The conductivity method for measu...

AI Technical Summary

Problems solved by technology

However, since the measuring electrode of the electrode type salinity meter is directly in contact with seawater, it is prone to problems such as polarization, corrosion and pollution by seawater, which will cause performance degradation, which seriously limits the application in the field, so it is mainly used in the laboratory for high Accuracy measurement

The current salinity meter has a relatively low degree of automation, and many manual adjustments lead to complex system operation and low measurement efficiency. The measurement accuracy and stability also need to be improved.

[0004] In recent years, with the gradual increase in the demand for marine hydrological observations, the original seawater salinity meter can no longer meet the needs of modern ocean rapid monitoring, so there is an urgent need for intelligent and high-precision seawater salinity meters

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