共查询到20条相似文献,搜索用时 140 毫秒
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嵌入式工业设备网关是实现工业现场设备和以太网互联的新型网络接口设备,适用于改造现有的现场总线网络,在使用现有的现场总线控制网络的情况下,又实现了与Internet的集成,解决了设备的直接上网问题。在分析工业设备远程监控的新需求现场总线的局限性以及现场总线和Internet技术逐渐融合的基础上,提出了适合于改造现有现场总线和Internet互联的解决方案,即采用基于Internet的嵌入式工业设备网关实现设备直接上网。阐述了现场总线和TCP/IP网络之间的协议转换模型,最后给出其在工业自动化中的典型应用方法以及应用前景和发展趋势。 相似文献
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利用代理服务器,将PROFIBUS现场总线集成到PROFINET系统中,构成集成控制网络下的PLC控制系统。PROFINET连接监控级设备和控制级设备,采用TCP/IP协议,现场级采用PROFIBUS总线,控制网络组态及控制程序编写使用STEP7软件,系统监控功能用WINCC软件实现。由于PROFINET的各项优势,其在过程控制中的应用也将越来越广泛。 相似文献
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《工业仪表与自动化装置》2013,(1):11
现场总线基金会和ISA100无线协作提出设备集成结构模型2012年12月19日,现场总线基金会宣布与美国仪表学会自动化标准委员会ISA100合作提出了一个共同框架,允许多个工业通信协议通过共享无线集成网络在过程自动化系统中运行。这项工作的完成是基金 相似文献
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PROFINET的组成及其应用 总被引:1,自引:0,他引:1
文中详细阐述了PROFINET的主要组成部分:分散式现场设备及分布式自动化,以及客户所需的统一通信和现场总线集成等.PROFINET可以实现与其他现场总线的无缝集成,从而保护了商家的已有投资.PROFINET的应用,增强了生产过程的透明度,优化了系统运作. 相似文献
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基于离散时间排队理论的PROFIBUS总线性能分析 总被引:1,自引:0,他引:1
现场总线协议的实时性是评价总线性能的关键因素。该文根据PROFIBUS令牌总线协议原理,利用离散时间休假排队理论,建立了一个具有时间限量DMAP/M/1休假排队模型,然后对该模型进行了详尽的分析,求出了响应等待时间的数学表达式,给出了仿真结果。该文的研究为分析和优化令牌总线协议提供了理论依据。 相似文献
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在模态综合技术基础上,研究了子结构之间的柔性连接处理,提出了一种基于DMAP的模态综合实现方法,开发了一个具有模态综合求解功能的CAE系统,最后通过2个实例对所开发的系统进行了验证。结果表明,系统可以实现模态综合计算功能,能够精确地获得装配结构的低阶模态频率。 相似文献
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阻变存储器是一种新型非易失性存储器,其在外加电场作用下可实现高阻态和低阻态之间的切换。存储器电极材料和活性层材料的选择及相互作用是实现器件阻变特性的主要因素。石墨烯是具有优良导电性和高延展性的二维材料,通过激光加工还原氧化石墨烯是高效获取石墨烯的极佳方法。传统存储器的制备过程复杂,不利于大规模加工制造。以金属金(Au)和还原氧化石墨烯(rGO)作为电极,氧化石墨烯(GO)作为阻变层进行器件制备,很好地实现了存储器的阻变功能。简单高效的制备方式为大规模、高集成化生产阻变存储器提供了参考。 相似文献
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Distributed Large-Volume Metrology (LVM) systems are mainly used for industrial applications concerning assembly and dimensional verification of large-sized objects. These systems generally consist of a set of network devices, distributed around the measurement volume, and some targets to be localized, in contact with the measured object's surface or mounted on a hand-held probe for measuring the points of interest. Target localization is carried out through several approaches, which use angular and/or distance measurements by network devices.This paper presents a new methodology to support the design of networks of devices, for distributed LVM systems based on triangulation (i.e., systems in which network devices perform angular measurements only). It is assumed that these systems use multi-sensor networks including two typologies of devices: some are accurate but expensive and other ones are less accurate but cheaper. The goal of the methodology is establishing a link between the following parameters: (i) density of network devices, (ii) mix between the two typologies of network devices, (iii) measurement uncertainty, and (iv) cost. The methodology allows to estimate the most appropriate density and mix between the two typologies of network devices, so that the distributed LVM system is conforming with the required measurement uncertainty and cost.The methodology relies on a large number of simulated experiments, defined and implemented using a dedicated routine; feasibility and practicality is tested by preliminary experiments on a multi-sensor photogrammetric system, developed at Politecnico di Torino—DIGEP. 相似文献
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利用阻尼材料改善驾驶室声学特性的研究 总被引:2,自引:0,他引:2
为改善某款商用车驾驶室声学特性,建立该驾驶室的声固耦合有限元模型,通过频率响应分析,得到车内的声学响应。对81 Hz处声压峰值进行声学结构模态参与因子分析和板件贡献分析。对贡献最大的板件进行自由阻尼处理。为减少阻尼材料使用量,将阻尼材料体积作为约束条件,阻尼材料单元相对密度作为设计变量,以贡献最大的结构模态所对应的模态阻尼比最大化为优化目标,基于优化准则算法用MSC.Nastran的直接矩阵提取程序(Direct matrix abstraction program,DMAP)语言编制拓扑优化程序,对阻尼材料在驾驶室上的分布进行优化。优化后阻尼材料的体积减小40%,目标模态的模态阻尼比降低5.2%。根据优化结果粘贴阻尼材料,使驾驶员右耳处声压和乘员右耳处声压在81 Hz附近分别降低11.2 dBA和10.7 dBA,其他峰值处声压变化不大。 相似文献
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Guohui Zhang Youping Chen Chuming Yuan Zude Zhou 《The International Journal of Advanced Manufacturing Technology》2006,29(3-4):336-341
A data-centered architecture for an industrial process monitoring system (PMS) is proposed. In such a system, the elements
of graphical user interface (GUI) can be used to simulate the working process of practical devices by their state data, because
a change of devices’ state will cause some properties of graphic elements to vary. And by operating the graphic elements,
the user can first handle the monitoring data, and then operate the devices indirectly since the changed monitoring data will
be inputted into the devices, and ensure their control. A configurable platform, which consists of tools such as project manager,
GUI developer, system builder, etc., is developed to customize a specific PMS for different types of devices. The procedure
of configuring a specific PMS with the platform is detailed. Then, the reconstructing and working process of the specific
PMS is described. 相似文献
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Neboja I. Jaki Gary P. Maul 《International Journal of Flexible Manufacturing Systems》2002,14(3):227-248
Vibratory bowl feeders (VBFs) are machines that feed various small parts in large volume automatic assembly systems. Their shortcomings, like inflexibility and the propensity to jam, stem from the use of mechanical orienting devices. Air jet based orienting devices can be implemented to overcome these limitations. Applications of passive and active air jet based orienting devices that replace conventional devices for the VBF are discussed. Passive devices, which reject incorrectly oriented parts, are discussed first. Active air jet based orienting devices are introduced to further improve the flexibility of VBFs. Since active devices reorient parts into a desired orientation, the part motion under their influence is analyzed. A number of tests demonstrate the feasibility and advantages of these new orienting devices. 相似文献
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自聚焦超晶格波导电光调制器 总被引:4,自引:4,他引:0
研制了一种基于自聚焦超晶格薄膜电光波导调制器.首先给出了自聚焦超晶格薄膜电光特性的测量和器件结构的优化设计,采用测量二次谐波生成值对入射角的依赖关系测定了薄膜的有效电光系数,保证了器件的设计精确有效.利用多层膜传输理论研究了器件电极对光波的最大吸收,并对器件结构进行了优化,获得了最小调制电压.其次给出了所加工的实验模型结构和扫描电子显微镜(SEM)图片,确保了加工质量和设计结果的一致.研究结果表明:这种无需外电场极化处理的新型聚合物薄膜电光调制器加工难度小,并且光学损耗优化到了1.0dB/cm. 相似文献
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为开发高温释放型烟用香料添加剂,本研究以2,3-吡嗪二羧酸和薄荷醇为原料,N,N′-二环己基碳酰亚胺(DCC)为缩合剂,4-二甲氨基吡啶(DMAP)为催化剂,经酯化反应制备了新型潜香目标化合物2,3-吡嗪二羧酸薄荷醇酯。该化合物经X射线单晶衍射、核磁共振波谱(1H NMR,13C NMR)、红外光谱(IR)和高分辨质谱(HRMS)表征后,结合同步热稳定性分析,采用在线热裂解 气相色谱/质谱(Py-GC/MS)法对裂解产物进行定性和半定量分析,并初步推测了其可能的裂解机理。结果表明:在主要热失重区间268.5~334.9 ℃范围内,目标化合物基本分解完全,熔融温度为140.9 ℃,裂解温度为315.9 ℃;共鉴定出目标化合物的46种裂解产物,主要有薄荷烯、薄荷醇和吡嗪等多种对烟草香味有重要作用的致香成分。该方法能够方便、快速地分离鉴定高温食品香料添加剂的热裂解产物,可为该添加剂在烟草中的加香应用提供理论参考。 相似文献
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Various kinds of low-light-level detectors and image intensifiers are described and specific charge-coupled device (CCD) developments are discussed from the perspective of the astronomical community, with possible application to optical microscopy. A number of research groups are reporting success at obtaining custom CCDs for application to high-quality cameras working at low-light levels. CCDs offer significant advantages in image quality and sensitivity compared with more traditional devices. Signal to noise (S/N) is derived for both CCDs and intensified devices. There is a tradeoff between the two and, because of the high read-out rate required by microscopists, intensified devices still offer a S/N advantage at the lowest light levels. 相似文献