The Research Of Ocean Current Sensor Signal Acquisition System

The development and utilization of ocean is good for us.China attaches greatimportance to the exploitation of ocean resources.But there is no specialized rising flowcurrent seneor in Chia.The research of rising flow has important economic value.Thedesign of rising flow current sensor is imminent.The output signal of current sensor is very weak.The amplitude of the signal is in tensof microvolts magnitude.The acquisition of the weak signal is very difficult.Through theanalysis of the weak signal detection technology, it is found that the key of weak signalacquisition is the noise suppression.First,from the perspective of reducing noise, we abandon the traditional signalacquisition method,put forward the innovation of the decrease in the number of analogcomponents.And we use analog to digital converter AD7714to prosess the signaldirectly, which has amplifier and filter function.It can effectively reduces the noiseintroduced in the device.Secondly, in the hardware design, the system uses a lithium polymer battery and aprecision low noise liner voitage circuit.The analog-to-dianal conversion circuit usingratio measurement way can eliminate the influence of power fluctuation of the signalacquisition. Through the analysis of various noises probably mixed in the signal, we usereasonable shielding and grounding to reduce the noise to the minimum.Once again, the acquisition system designed with digital filter algorithm and24bitshigh precision ADC can ensure the accuracy of data acquisition syetem.According to the above design ideas, we set up a complete signal acquisitionsystem.It can complete the analog to digital conversion of the signal,digital filter,timerecoding and the data storage.We design a data display,storage and analysis softwarebased on LabVIEW. The software realizes the collection, analysis of the current sensorsignal conveniently.Finally,through the experiment,we test the accuracy of current sensor signalacquisition system.Test results show that the system precision is up to±0.875microvolts.It proves that current sensor signal acquisition system designed in this papermeets the accuracy requirements of the current measurement.