Design Of Data Acquisition System For Deep Ocean Moored Buoy

In the 21 st century,the exploration of the sea has entered a new historical stage.The proportion of marine economy in the national economy is getting higher and higher,and the important strategic position of oceans in military affairs is becoming increasingly prominent.The ocean has become an area we cannot ignore.The development of Marine economy is inseparable from ocean exploration.Only by understanding the ocean,we can develop the sea better.Ocean data buoy is one of the most important means of ocean monitoring.It has the ability to measure the meteorological and hydrological information of the designated sea area in long-term and continuous unattended condition.It can provide effective data support for shipping,marine exploration,marine atmospheric research and even military operations.Due to the late start of buoy research in China,some buoy technologies lag behind other ocean powers.In order to promote the rapid development of buoy technology in our country and promote the process of localization of buoy technology,this paper independently developed a data acquisition system for buoys.Each link of the system design(including chip selection,circuit design,PCB production,programming and system verification)is completed by us.The system uses the STM32 microcontroller of ARM core as the main control chip,which has rich peripherals and supports multiple communication interfaces.The analog signal of the sensor is acquired by ADI 24-bit high precision Analog to Digital conversion chip.ADR43 X series chips with high precision and low noise are used to provide reliable voltage reference for AD conversion chips.In the process of PCB design,single point ground,Isolation of Digital Power and Analog Power,Isolation of Digital ground and Analog ground,etc.This design effectively improves the accuracy of analog signal measurement and reduces the conversion noise.The system can simultaneously measure multi-channel differential analog voltage signal and multi-thermistor sensors,which can satisfy the measurement of wind speed,humidity,air pressure,long-wave radiation,short-wave radiation,compass,rain gauge and PT100 analog sensors of buoys.The system uses inductively coupled transmission to read underwater CTD data.There are 13 CTDS of different types in the system,which are distributed in different depths of water.The data returned by CTD through inductive coupling is received by the controller through serial port,and the ADC chip communication with the controller by the SPI interface.The controller stores the measured data of various sensors in SD card and sends them to the ground shore station system every three hours through Iridium satellite.Finally,the system is calibrated and the experiment of testing machine is carried out.After calibration,the accuracy of voltage measurement can reach more than 0.1 mV.In view of the stability of the system,sufficient testing machine work is carried out.During the process,the system runs normally,and the measured data are basically consistent with the data released by the meteorological station,which shows that the system has reliable performance and can complete the data acquisition of deep-sea buoys.