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1.
介绍了以PLC为核心的端面、外圆半自动磨床的电气控制系统改造设计方案,该方案已成功地运用于生产实践多年。实践证明,改造后的磨床在可靠性、稳定性等方面有极大的提高。  相似文献   

2.
本文以一个实际技改项目为例,详细介绍了利用PLC对轴承磨床电气控制系统进行改造。系统以PLC为控制核心,取代原有的继电器———接触器控制系统,减少了中间继电器,使线路得到简化,提高了可靠性。  相似文献   

3.
PLC步进式伺服系统的研究   总被引:1,自引:0,他引:1  
本文主要研究可编程序控制器(PLC)在步进式伺服系统中的应用。提出采用EX100PLC主机,辅以32点DC输出模块(DO32)或轴向定位模块(MC11)来控制步进电机,并用于精密磨床的进给控制的两种方案,分别进行了硬软件设计、完成实验室试验,并对两种控制方案的特点进行了分析研究。  相似文献   

4.
在工业生产中,磨床的作用相当重要,对于提高产品的精度意义重大。长期使用后,磨床砂轮会渐渐磨损,出现误差,使磨床的精度下降。为了补偿磨床出现的误差,将西门子PLC、步进电机、位移传感器,模拟量模块EM235等进行组合,设计出一套完整误差自动补偿系统。该系统可对磨床砂轮位置进行实时调整,使砂轮的位置始终控制在误差允许范围内,从而提高产品制作的精度,满足实际工艺的需要,为提高产品的质量做适当而必要的调整。  相似文献   

5.
设计了一套模拟平面磨床液压站的实验装置,主要由液压站本体和PLC控制系统组成,可以实现磨床平台移动、举升滑移和自动润滑等功能,液压系统引入了比例压力阀和比例溢流调速阀,通以触摸屏作为人机交互界面,可进行磨床移动平台的压力和速度设置。基于液压比例控制技术的磨床液压站控制在机电液控制技术领域具有很好的代表性,将其引入到学生的专业教学中是一个很好的选择。该装置综合了液压系统设计、电控电路和PLC程序设计等专业技术。开发了配套实验项目,对于培养学生综合应用专业技术和实践创新能力具有实质性意义,满足新工科创新型卓越工程师的培养需求。  相似文献   

6.
可编程序控制器(PLC)以其高可靠性、灵活性、通用性等特点,成为实现工业生产自动化的支柱产品。本文介绍了PLC在湿法鱼粉生产线改造中的应用,利用PLC代替继电器控制,可简化控制线路,提高控制系统的可靠性,体现了PLC控制系统优于传统的继电器控制系统。  相似文献   

7.
西门子PLC具有强大的网络控制功能,介绍了利用西门子PLC的PID控制功能来实现的直流调速闭环控制系统,该系统利用了西门子PLC的网络控制功能,通过工业以太网、Profibus—DP现场总线来实现调速系统的远程监视及控制,提供了一种实用的工业以太网、现场总线的互连方案.  相似文献   

8.
磨床控制系统的应用与研究   总被引:1,自引:0,他引:1  
磨床上的砂轮一般采用绕线式交流异步电机驱动,基停子绕组通过滑环可以与外部电路连接,根据磨床的工作特性,选择从其转子侧引入控制变量来实现调速,采用机械串级调速系统对其进行控制,使其具有高效率和良好的调速性能,实践证明,采用该方法实现磨床控制,其系统结构简单,可靠性高,节能效果好。  相似文献   

9.
1.引言 80年代,微电子技术和计算机技术迅猛发展,使得PLC有了突飞猛进的发展,其功能日益加强,可进行模拟控制、位置控制、远程通信等,故PLC(其功能已近超出逻辑控制范围,习惯上依然这样称呼)被称为现代工业控制的三大支柱(即:PLC已应用工业自动化和各个领域),所以对PLC系统故障的排除至关重要。  相似文献   

10.
PLC控制的步进电机频率曲线优化技术研究   总被引:3,自引:0,他引:3  
PLC(Programmable Logic Controller)控制步进电机在许多工业控制中应用广泛,本文介绍了PLC通过发送脉冲和方向信号给步进电机的驱动器,由驱动器来控制步进电机工作的原理.并研究了步进电机的频率曲线,分析总结出用PLC控制步进电机使运动小车的运行速度最优化,并在中药自动配药系统中以实验数据证明了步进电机在PLC控制下的频率曲线优化的可行性.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

14.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

15.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

16.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

17.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

18.
For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the  相似文献   

19.
Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of  相似文献   

20.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

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