Design And Research Of New-type Ocean Temperature Salinity And Depth Measurement Circuit System

The ocean temperature salinity and depth measurement system is a system for measuring the temperature,conductivity,and depth parameters in the ocean,referred to as CTD.The Measured parameters of temperature salinity and depth are the most basic and critical parts in the field of the hydrographic survey.It is of great significance to both the military and civilian fields.Europe,the United States and Japan started earlier in this field and are currently at the International leading level.China started late in this field and its technological foundation is relatively weak.As the country pays more and more attention to the field of ocean parameter measurement,China's instrument of measuring the temperature salinity and depth in the ocean is also rapidly developing and improving,but there are still many problems to be solved.Aiming at the problems existing in the current measurement system,this project discussed and implemented an improvement scheme,and carried out the design and research of a new-type ocean temperature salinity and depth measurement circuit system.This subject is guided by theory.The measurement method of temperature salinity and depth parameters is discussed.This solution decided to use a thermistor to measure the temperature,a seven-electrode sensor to measure the conductivity,and a strain-type pressure core to measure the depth.In the most complicated conductivity parameter measurement section,a direct measurement method of voltage and current is used to improve the accuracy and stability of the circuit.The implementation process mainly includes three parts: sensor selection and production,measurement circuit design and host computer system design.The sensor is the basis of the measurement system.In this paper,the selection instructions for the temperature and pressure sensors are made,and a new low-cost electrode design scheme is given for the existing problems of the seven-electrode sensors.The circuit design is divided into a digital circuit part and an analog circuit part.Digital circuits include single-chip microcomputer system circuit,communication circuit,and storage circuit;analog circuits include temperature measurement circuit,pressure measurement circuit,excitation signal generation circuit,signal sampling circuit,electrode voltage measurement circuit,shaping circuit,and data acquisition circuit.The software design part includes the software development based on the single-chip microcomputer system and the software development based on the upper computer,which realizes the low-power operation mode of the system,and ensures the effective operation of the system and the effective interaction of data.The measurement system is therefore more intelligent.Finally,through a large number of experiments and tests,the measurement accuracy of the system is obtained,which meets the requirements of the measurement index,and verifies the feasibility of the scheme.