High precision data acquisition of control system for high-power TEA CO2laser based on DSP
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摘要:针对基于DSP的高功率TEA CO2 器控制系统直接利用DSP F2812内置A/D转换器(ADC)进行模拟量采样时存在转换误差较大,且模拟量易受电磁干扰等问题,从硬件和软件两个角度提出了校正DSP2812内置ADC的方法。硬件上采用硬件模拟滤波和隔离等手段对输入的模拟量进行处理;软件校正则通过将两路给定的参考电压值送入DSP F2812内置A/D转换器的两个转换通道,计算出ADC的偏置误差和增益误差,以此误差对其它通道A/D转换器进行校正。最后,实验分析了参考电压和A/D采样时钟频率对A/D转换精度的影响。结果表明,提出的方法能有效地提高A/D转换器的精度,A/D转换误差达到3 LSB,特别是在对腔压值精度要求很高的0~12 000 Pa区段,A/D转换精度达1 LSB,可以保证TEA CO2 器的可靠运行。
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关键词:
- 高功率TEA CO2 器/
- 数据采集/
- DSP F2812/
- A/D转换/
- 误差校正
Abstract:It shows larger conversion errors and stronger electromagnetic interference when the AD converter(ADC) built in DSPF2812 of the control system for a high-power TEA CO2 laser based on the DSP is used to acquire analog signals. To overcome the backcomings, a method to correct the ADC built in the DSPF2812 was proposed based on both the hardware and software. In hardware processing, the analog filtering and isolation module were adopted to process the input analog signals and the median average filtering method was used to eliminate the occasional glitch. With software correction, two given reference voltages were sent to the two channels of the A/D converter of the DSPF2812 to calculate the offset error and gain error, then it was used to correct other channels of the A/D converter. Furthermore, the impact of the reference voltage and A/D sample clock on the A/D conversion precision was analyzed by experiments. The experimental results show that the method can improve the precision of the A/D converter effectively. The A/D conversion error has been within 3 LSB, which can ensure the stability and reliability of data acquisition for the control system in high-power TEA CO2 lasers. -
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