PLC控制系统中几种降低成本的方法

以欧姆龙公司CPM1 A型PLC为例,通过改变硬件接线和巧妙运用软件编程的方法,降低了PLC控制系统的成本,提高了PLC在工业控制系统中的性价比.     

一种基于PLC的智能交通灯控制系统设计

针对我国城市交通拥堵的现状,从控制系统设计上,应用可编程控制器PLC设计出智能交通灯控制系统以解决交通拥堵。在十字路口相应的位置预埋传感线圈,对此路段上的车流量进行统计,并根据车流量的变化,改变绿灯的控制时间,可以实时地对绿灯资源进行合理调配,提高十字路口的通行能力。     

一种新型的数字式液位——流量控制系统综合实验装置

本文介绍了一种新型液位一流量控制系统实验装置-数字式液位流量控制系统，它改变了传统的过程控制中通过模拟量控制来实现对液位流量的控制的方法，采用了以数字调节器为核心的控制系统，具有结构简单，高运算能力，高精度的特点，为学生实验提供了良好的对象，适应了当今数字化时代的要求。     

基于在弱磁范围内直接转矩控制系统恒功率调节的研究

直接转矩控制系统具有控制结构简单、动态响应快等特点,它在很大程度上解决了矢量控制中计算复杂、特性易受电动机参数变化的影响、实际性能难以达到理论分析结果的一些重要技术问题．在弱磁范围内,由于定子磁链空间矢量在全电压控制时是以最大的轨迹速度旋转的,所以改变磁链给定值大小,也就改变了路径的长短,从而达到改变角的大小而调节转矩的目的．弱磁范围内直接转矩控制系统恒功率调节已成功的应用于大功率的电气传动控制,是一种具有较高动态响应的交流调速控制技术．     

基于单片机的Buck电路控制系统的设计

以常见的Buck电路为主电路,采用带有PWM的单片机作为控制电路,建构一个基于C8051F系列单片机的Buck电路的光伏一蓄电池的能量控制系统,并通过改变占空比,来改变电路的电流和电压,实现光伏电池的最大功率跟踪与蓄电池浮充两大功能。测试表明,该方案合理有效。     

浅论嵌入式控制系统在发电厂中的应用

随着计算机技术和半导体技术的发展,嵌入式控制系统已经和正在改变着传统的集散控制系统的控制模式、网络拓扑结构、控制策略。对于火力发电厂的控制领域,嵌入式系统的应用必将更加广泛和深入。     

智能照明控制系统分析——以上海环球金融中心会议区为例

传统的照明控制系统只是简单的打开和关闭,工作模式和控制方法单一,难以改变照度和场景,营造出舒适的氛围。随着信息时代的来临,智能照明控制系统应运而生,它完备的控制功能和预置的多种可切换场景可以满足用户多样的需求。本文重点分析了环球金融中心会议区的智能照明控制系统。     

基于PC104与ADT-834运动控制卡的伺服电机控制系统

设计了一种通过嵌入式系统与运动控制卡来驱动伺服电机的控制系统。系统在DOS下用BorlandC++3.1语言实现,启动后系统根据接收到的不同的控制要求调用控制卡的运动函数库,以改变伺服电机的脉冲频率和方向信号,实现对伺服电机的运动控制。     

基于FPGA的激光器功率控制系统设计

以FPGA芯片为控制核心结合相关的外围器件完成了激光器功率控制系统的设计.通过FPGA控制数字电位器DS1867实现了对激光器电源内部电阻的控制,改变激光器发射功率等级的目的.同时系统还实现了检测激光器所在环境的温度,及高温报警、定时控制等功能.     

永磁同步电动机转速专家控制

针对永磁同步电动机(PMSM)的动态数学模型、参数改变及易受外界干扰,提出了一种基于专家控制的PMSM转速控制系统.利用专家控制算法对PMSM控制系统进行了Matlab仿真分析,并与PI控制算法进行了比较,验证了所提控制系统具有良好的动态特性和鲁棒性.实验结果表明,该控制系统响应速度快,超调小,系统运行稳定.     

卡思卡特城堡

It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,     

不同的吃喝玩乐

一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/     

漏洞百出的教育

Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help?     

只要努力,不要后悔

There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love.     

浅谈移民问题

Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject.     

Sister Carrie, an Adherent of Desires

Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities.     

Improvement of one-cycle controller by use of proportional integral differential controller

1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec…     

库克斯顿城堡

城堡, 是欧洲典型的建筑之一, 每个城堡都有一个美丽的传说或是一段历史。从本期开始, 我们将推出“城堡之旅”, 带各位读者去浏览、观赏欧洲各地的城堡, 开始一段文化与历史的旅途!     

胡主席在印度,我却在中国

Today, Sunday morning, I sit thinking and typing at my computer. My thoughts are in my homeland, India and my body is in China. The body is here and mind there for a good reason. Mr. Hu is president and I am resident and both are in each other's countries (what a difference the absence of one small letter makes!). Mr. Hu will return in a few days and I will stay on longer.