To evaluate and improve the real-time performance of Ethernet for plant automation（EPA） industrial Ethernet,the real-time performance of EPA periodic data transmission was theoretically and experimentally studied.By...To evaluate and improve the real-time performance of Ethernet for plant automation（EPA） industrial Ethernet,the real-time performance of EPA periodic data transmission was theoretically and experimentally studied.By analyzing information transmission regularity and EPA deterministic scheduling mechanism,periodic messages were categorized as different modes according to their entering-queue time.The scheduling characteristics and delivery time of each mode and their interacting relations were studied,during which the models of real-time performance of periodic information transmission in EPA system were established.On this basis,an experimental platform is developed to test the delivery time of periodic messages transmission in EPA system.According to the analysis and the experiment,the main factors that limit the real-time performance of EPA periodic data transmission and the improvement methods were proposed.展开更多
The resistance spot welding plays an important role in automotive industry. The electrical parameters （power supply voltage, welding current, SCR firing angle and current flow angle） of welding process can reflect t...The resistance spot welding plays an important role in automotive industry. The electrical parameters （power supply voltage, welding current, SCR firing angle and current flow angle） of welding process can reflect the quality of joint and the status of welding equipment, many data acquisition devices designed to collect those parameters have been discussed in many papers, but there is such a deficiency that one computer can only link with an acquisition device. At automobile assembly field, there are hundreds of welding machines working at the same time, so the existing device can not be satisfied with manufacturing demand. To solve the problem, the double-MCU data acquisition device based on Ethernet is discussed in this paper, the data acquisition devices can altogether link with a computer using a HUB, the effective value or the instantaneous value of electrical parameters can be transmitted to the computer over UDP/IP. All the data are read through Ethernet port of a computer using a LabView application, which can process, store and present all data to the user. Finally the experiments prove that the designed Ethernet-based data acquisition system is suitable for practical application.展开更多
为适应长征四号系列运载火箭控制系统的新状态、新需求,进一步提高控制系统测试覆盖性、消除安全隐患,对运载火箭测试系统开展了技术研究。通过梳理测试系统的功能,提出了一套基于面向仪器系统PCI扩展(PCI Extensions for Instrumentati...为适应长征四号系列运载火箭控制系统的新状态、新需求,进一步提高控制系统测试覆盖性、消除安全隐患,对运载火箭测试系统开展了技术研究。通过梳理测试系统的功能,提出了一套基于面向仪器系统PCI扩展(PCI Extensions for Instrumentation,PXI)技术的运载火箭实时监测系统,该套系统以PXI计算机为核心,结合模拟量采集、数字量采集、实时以太网和数据自动识别判读等技术,可完成该型号背景下的调试、试验和验收工作。测试数据表明,测试系统数据处理正确、系统匹配性合理、测量精度高,通用性强,在高态势的发射需求下,具有很好的应用前景。展开更多
基金Supported by the National High Technology Research and Development Program of China (2006AA040301-4,2007AA041301-6)
文摘To evaluate and improve the real-time performance of Ethernet for plant automation（EPA） industrial Ethernet,the real-time performance of EPA periodic data transmission was theoretically and experimentally studied.By analyzing information transmission regularity and EPA deterministic scheduling mechanism,periodic messages were categorized as different modes according to their entering-queue time.The scheduling characteristics and delivery time of each mode and their interacting relations were studied,during which the models of real-time performance of periodic information transmission in EPA system were established.On this basis,an experimental platform is developed to test the delivery time of periodic messages transmission in EPA system.According to the analysis and the experiment,the main factors that limit the real-time performance of EPA periodic data transmission and the improvement methods were proposed.
文摘The resistance spot welding plays an important role in automotive industry. The electrical parameters （power supply voltage, welding current, SCR firing angle and current flow angle） of welding process can reflect the quality of joint and the status of welding equipment, many data acquisition devices designed to collect those parameters have been discussed in many papers, but there is such a deficiency that one computer can only link with an acquisition device. At automobile assembly field, there are hundreds of welding machines working at the same time, so the existing device can not be satisfied with manufacturing demand. To solve the problem, the double-MCU data acquisition device based on Ethernet is discussed in this paper, the data acquisition devices can altogether link with a computer using a HUB, the effective value or the instantaneous value of electrical parameters can be transmitted to the computer over UDP/IP. All the data are read through Ethernet port of a computer using a LabView application, which can process, store and present all data to the user. Finally the experiments prove that the designed Ethernet-based data acquisition system is suitable for practical application.
文摘为适应长征四号系列运载火箭控制系统的新状态、新需求,进一步提高控制系统测试覆盖性、消除安全隐患,对运载火箭测试系统开展了技术研究。通过梳理测试系统的功能,提出了一套基于面向仪器系统PCI扩展(PCI Extensions for Instrumentation,PXI)技术的运载火箭实时监测系统,该套系统以PXI计算机为核心,结合模拟量采集、数字量采集、实时以太网和数据自动识别判读等技术,可完成该型号背景下的调试、试验和验收工作。测试数据表明,测试系统数据处理正确、系统匹配性合理、测量精度高,通用性强,在高态势的发射需求下,具有很好的应用前景。
