High-speed Data Acquisition System Design Based On Fpga

The paper presents the design of online initial crystallization temperature acquisition system based on FPGA. The initial crystallization temperature means the temperature that aluminum electrolyte begin to crystallize. It is very important to measure the accurate initial crystallization temperature, because it is used to monitor the electrolytic aluminum production process, control the minimum superheat, lower the energy consumption, stabilize the production operation, improve the life of electrolyzer, strengthen the current efficiency. This article introduces the embedded temperature acquisition system design methods based on FPGA from several aspects, which are the architecture of the system, the design of the hardware, the design of FPGA and the design of the man-machine interaction.The system use thermocouple which is temperature-sensitive to measure the temperature of aluminum electrolytic in the front end of the system. The thermocouple can convert the temperature signal to the electromotive force, and the electromotive force can transmit through the compensation wire into the signal conditioning circuit of the equipment, the conditioning circuit consists of an amplifier by the INAl18to magnify the signal20times, the low-pass filter by the OP297, the second differential amplifier by TFIS4131to magnify the signal12.5times, and transfer the single-ended signal to differential signal, then the signal can be converted by the analog/digital converter after the signal conditioning circuit, the converted data is sent to the FIFO within the FPGA, when the data up to half of the capacity of the FIFO, FPGA issued interrupt to the microcontroller OMAP3530. The FPGA controls the signal conditioning, analog/digital conversion, data storage and transmission as the controller chip of the front-end. At last, the processor OMAP3530processes and displays the data from FPGA. The equipment uses Windows CE operating system to provide a good platform for human-computer interaction, it is very convenient for the workers to operate the equipment. The application software in the equipment can display the cooling curve and initial crystallization temperature very well, so it is more intuitive to guide the daily operation of the workers.