Based Dsp Triaxial Data Acquisition System Development,

Triaxial instrument is one kind of basic science research apparatuses. It aims at studying earth stress-strain analysis. With the development of triaxial instrument experimentation, more and more data is required to be processed, as well as real-time and precision is desired to be enhanced .So initial triaxical instrument can't meet the demand of soil test.Considering above-mentioned problems, the technique requirements of triaxial instrument in soil test and the applications of DSP in data acquiring and signal processing are analyzed. A muti-channel, high-precise data acquisition system based on DSP techniques has been designed for implementing data acquiring, filtering and processing .The main work of this paper is showed as follows:In the aspect of hardware, According to the actual conditions of data-acquiring and processing in triaxical instruments and previous research on mechanism, a multi-channel, high-precision data acquisition card based on SPI-BUS, TMS320LF2407 and AD7660 is successfully designed .The circuit design and the design method about analog signal processing, DSP and LCD extended module are emphasized.In the aspect of software, main achievements include:First, software design for each module of data acquisition systems and analysis on logic timing of A/D are elaborated and the software program flowcharts are also givenSecond, the acquisition and processes of signal is further studied. Due to application of the oversampling and digital filter techniques during the signal processing, sample resolution is improved from the aspect of software under the same bit of ADC; simultaneously the demand of hardware for analog filter is reduced.Third, the implementation and algorithm of FFT in fixed-point DSP are studied, so that the acquired stress signal can be completely analysed in the frequency domain.By using of the triaxial instrument data acquisition system, the acquisition and processing of soil pressure signal are accomplished. The soil structure relationship that is an internal relation between the soil stress, strain, intensity and time and the interaction rule between soil and structures are validated .The soil theory of intensity -distortion is established. Results show that the designed triaxial instrument data acquisition system can meet the demand of triaxial experimentation.