四层电梯系统S7-200 PLC控制及其电路故障原因分析

介绍了S7-200 PLC对四层电梯的控制原理,并重点分析了S7-200 PLC控制系统和外围电器的故障原因。     

PLC程序中移位指令在顺序控制系统中的应用

顺序控制是PLC控制中常见的控制功能,编程简单易学,但在西门子S7-1200、S7-200smart等中小型PLC中没有SFC流程图的编程方式,需要将流程图转换为梯形图,转换过程较麻烦。以机械手取放料、三自由度机械手取放料和8工位转盘为例,介绍移位指令在顺序编程中的应用。实际应用证明,用移位指令实现顺序控制则使程序简单易懂,可以解决西门子S7-1200、S7-200smart等中小型PLC中没有SFC流程图编程方式的问题。     

基于PLC和伺服单元的自动涂胶系统的开发

针对某玻璃公司真空玻璃涂胶工作站改造项目的需求,对原有操作台进行机械和电气改造。利用光纤传感器和电磁传感器采集位置信号,西门子S7-200系列PLC采集和处理数据,通过安川∑-V系列SGDV伺服驱动单元对伺服电机进行速度控制,实现四边直线涂胶系统的全自动控制。系统具有手动和自动涂胶控制功能、位置检测、伺服报警和保护等功能。     

基于S7-300PLC和ET200S的电镀生产线自动控制系统设计

针对目前一些中小型电镀企业的生产工艺自动化水平不高,大多采用人工作业的不足之处,文章开发设计了一种基于S7-300 PLC和ET200S的电镀生产线自动控制系统。S7-300 PLC作控制器,通过两个分布式I/O系统ET200S控制两台行车按规定的生产工艺运行,S7-300 PLC通过PROFINET工业以太网与分布式I/O ET200S、变频器G120和触摸屏KTP600进行通讯。本系统具有自动和手动两种工作模式,操作维护方便,行车运行平稳,定位精确。     

汽轮发电机组试验监控系统设计

根据汽轮发电机组试验监控系统工作原理,设计了基于伺服电动缸排放阀、S7-300PLC、S7-200SMART PLC,以及LabVIEW为基础的汽轮发电机组试验监控系统。上位机采用LabVIEW软件开发,通过OPC技术和Modbus协议,建立了与PLC以及机组控制屏的通信。场地试验参数采用S7-300PLC采集,伺服电动缸排放阀、负载开关柜、水电阻采用S7-200SMART PLC控制,实现了试验数据的采集存储以及场地试验设备的控制功能。着重介绍了LabVIEW如何与2种PLC实现基于OPC技术的数据通信,以及首创的基于伺服电动缸排放阀技术的瞬态特性试验控制功能。     

西门子PLC控制大量步进电机的应用研究

神光Ⅲ工程的激光参数测量系统电控工程设计要求网络通信能力强,且系统可靠性高,而西门子PLC具有可靠性高、功能强大、使用方便、编程简单、抗干扰强等优点,在工业控制领域得到了广泛应用.采用西门子S7-200 PLC的两路脉冲输出控制2台步进电机,S7-300 PLc作为总的处理器处理多个S7-200的信息,同时与工业以太网之间采用PROFIBUS进行现场总线通信,实现了西门子PLC对大量步进电机的控制和与主控系统进行高效率通信的功能.在实验的基础上验证了该方案的可行性,并且它可以降低现场设备连接的工作量和费用,保证系统的可靠性.     

西门子S7-200 PLC在立轴圆台平面磨床控制中的应用

介绍了用西门子S7-200 PLC对M7475型立轴圆台平面磨床控制系统进行的改造.利用PLC控制系统,可实现磨床启动、停止、砂轮转动、工作台移动和工作台转动,并且砂轮升降有手动和自动两种控制方式；提供过载、断相、零励磁和零电压保护；并可根据所吸工件的大小,灵活调节电磁吸盘的吸力.     

基于PLC的步进电机控制系统设计

基于设计步进电机控制系统的目的,主要设计以PLC为核心控制器的步进电机控制系统。在对常见的三相反应式步进电动机工作原理详细阐述的基础上,对步进电机的控制原理进行分析说明。以西门子S7-200系列PLC对步进电机的控制为例,通过对S7-200系列PLC的高速输出点直接对步进电机进行运动控制的方案设计,设计相应的外部接线图、程序,并对具体的控制参数进行说明。     

基于Profibus的PLC控制系统设计

主要进行基于Profibus现场总线技术的PLC系统的设计方法的研究,并结合SIEMENS公司的S7-300 PLC、通讯模块ET200M、ET200S及OMRON C200HX PLC等相关产品组建Profibus-DP网络,讨论了STEP 7硬件组态、网络配置以及程序设计方法.     

基于PLC的水处理自动控制系统

介绍了水处理装置的工作过程,采用西门子S7-200 PLC+触摸屏进行控制。重点分析了系统硬件设计、硬件线路连接、PLC和触摸屏软件设计。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

Limits of topographic measurement by the scanning tunnelling and atomic force microscopes

Parameters describing the topographic character of a surface (height, surface wavelength, slope and curvature) can be derived from equivalent sinusoidal profiles. The response of a surface-measuring instrument may be modelled in terms of instrument parameters such as stylus radius, and scanning range and resolution. The performance of the instrument may then be mapped as a zone in amplitude-wavelength (AW) space to show the sinusoidal profiles it is capable of measuring. In a first-order analysis the STM and AFM are considered as equivalent to contact-stylus instruments with a notional stylus radius equal to the tip radius plus the gap. Comparisons between different instruments and types of instrument are readily made by mapping in AW space. The error arising from convolution of the sinusoidal profile with that of the finite tip may be quantified and plotted as contours in AW space.