Multi-parameter Acquisition And Analysis For Aluminum Reduction Process

Aluminum process is a multi-parameter, non-linearity, slow time-varying, highly corrosive and high energy consumption industry system. Many process carry through in the reduction cell. Among them anode voltage signal is one of the most important parameters to reflect cell status accuratelly. As a result, detection and analysis for this anode voltage signal is rather valuable and significant.Multi-parameter acquisition and analysis system for aluminum reduction cell in this paper takes PCI8602data acquisition card as the center. The system software has accomplished signal acquisition, display and disposal functions based on the simulation platform in lab.Aluminum reduction cell voltage signal achieved by direct memory access (DMA) method. Data transports between device and memory. That is to say, it could speed up the efficiency of data acquisition and processing greatly. Acquisition and display are realized by multi-thread.We use Hilbert-Huang Transform method to analyze the non-stationary aluminum reduction cell anode voltage signal. The expected finding is the graded separation of the high-frequency noise composition and the actual low-frequency composition. We adopt Empirical Mode Decomposition method to get the Intrinsic Mode Function. These functions include the partial feature of the signal in different time scales. Then Hilbert transform is used to get the instantaneous frequency of each intrinsic mode function. Finally the boundary spectrogram is shown and contrast with the FFT spectrogram. We find that the Hilbert-Huang Transform method is effective in extracting the frequency feature of the signal. At last display the analysis result in our system to accomplish data analysis function.Tools in the research and paper are Visual C++6.0, MATLAB, Microsoft Access2003. MATLAB software is used for data analysis and Access database is for data storage. Visual C++, as the upper computer software, realizes the data acquisition, real-time display and processing with a friendly interface.