Research And Design Of Sea Temperature And Pressure Acquisition System Based On PGA900

With the exploration of the Marine ecological environment,it is found that by observing the natural factors in the sea,some disasters can be prevented in time.By gathering and recording the changes in a certain depth of tide and water temperature in the sea,some catastrophic wave,sea ice,red tide,tidal wave and storm surge can be sensed in advance.However,due to the large size of the collection system,inconvenience of installation and excessive power consumption,it has brought great inconvenience to people's installation and use.Aiming at the above problems,this paper proposes a design scheme of sensor acquisition system with high accuracy,micro power consumption and miniaturization.In order to achieve high-precision acquisition and data fitting calibration for two physical quantities of pressure and temperature,the system adopts the PGA900 chip of TI company as the core of signal acquisition and conditioning.PGA900 is a two-channel 24-bit signal acquisition chip.It is also a programmable signal regulator,which realizes the signal conditioning in the film after the collection.In the calibration of the sensing signal,the temperature sensor signal is calibrated according to the zero position adjustment and the least square temperature compensation for the pressure sensor signal.In the implementation system of micro power consumption and miniaturization of the problem,first is the selection of system chips,are of high performance,low-power and small chip encapsulation,choose Actel company IGLOO series FPGA controller,use special Flash * Freeze sleep patterns and time interrupt manner between the system state conversion,make the system remain extremely low power loss in the static mode;In addition,different frequency clocks are used for different states of the system to further control the power consumption of the system.Finally,the power supply of the acquisition module and the bias conditioning module is closed when the output of the clock is stopped in the static mode of the system,and the power consumption of the system is reduced again.In the implementation of system miniaturization,except for the use of small chip packaging,the layout size of PCB is only 13mm×39mm,ensuring the realization of product miniaturization.In this paper,two key technologies of system micro power consumption design and high precision signal acquisition are presented.According to the test,the current of the system at work is about 5.58 mA,and the static state is 212?A,which meets the expected design requirements.After the pressure signal is compensated,the accuracy can be achieved within 0.1%.Meanwhile,the temperature sensor signal reaches the range of 0.1% after calibration,achieving the design goal.