非电中央空调Modbus RTU从站设计

采用Modbus RTU通信协议实现系统信息化集成是天然气分布式能源站提高能源利用率的有效管理方法,能源站系统中采用PLC控制的非电溴化锂中央空调主机通常采用程序扫描的方式实现Modbus RTU通信,通信效率低,本文针对程序扫描通信方式的缺点详细介绍了OMRON C200HG系列PLC使用中断方式实现Modbus RTU从站通信的设计方法,提高了非电溴化锂中央空调主机和能源站系统的通信效率．     

基于以太网和RS485总线的小型微网控制系统设计

为解决小型微电网中各元件之间数据实时通信的问题,提出了一种基于以太网和RS485总线的小型微电网通信结构.设计了配网代理、微网代理、元件代理的3层控制系统,采用Modbus/UDP协议和Modbus RTU协议分别作为配网代理和微网代理、微网代理和元件代理之间的通信协议.详细介绍了以太网和RS485串口通信的软硬件设计,以及Modbus/UDP和Modbus RTU协议转换单元.实验结果表明,在小型微电网控制系统中采用以太网和RS485总线,能够满足数据传输速率、实时性和可靠性的要求.     

STM32单片机与西门子Smart 700触摸屏通信的实现

建立了STM32单片机与Smart 700触摸屏的通信,分析了Modbus RTU通信协议的指令组成和格式、Smart 700触摸屏的基本通信方式、STM32单片机的通信特点,提出了STM32单片机通信程序设计方法.通过设计实验平台测试STM32单片机与Smart 700触摸屏间的Modbus RTU通信可靠性,实验结...     

基于 Modbus协议的单片机与触摸屏通讯系统设计

介绍了彩钢滚涂生产线上单片机与触摸屏通讯系统的硬件构成,重点讲述基于Modbus通讯协议的触摸屏与单片机系统的通讯方法.该方法降低了系统设计成本,并提高了设备的通用性.     

智能家居网络的串口通讯实现方案

目的 提出一种智能家庭网关与信息家电之间的串口通讯方案，设计一套基于RS-232的串口通讯协议。方法针对嵌入式系统在智能家居系统中的应用特点，参考电子控制领域通用的Modbus协议，并用C语言编制相应的串口通讯软件。结果建立了基于RS-232的串口通讯模型，实现了智能家庭网关与模拟节点之间的相互通讯。结论该智能家居网络的串口通讯方案是完全可行的。     

Modbus协议的变频控制器设计

针对Modbus协议相对于如局域控制网总线时间响应差的缺点,提出一种基于Modbus协议的变频控制器的设计方案. 根据VFD-L系列变频器Modbus具有Network ASCⅡ通讯模式的要求,设计RS-485通讯电路和通讯程序,并且在RS-485通讯电路的设计中重点考虑对干扰的屏蔽.系统以S3C44B0X芯片为核心,使用μC/OS-Ⅱ操作系统,配合S3C44B0X处理器构成软硬件环境,以增强Modbus协议在应用中的实时性能.     

Modbus通信协议在直流无刷电机控制系统上的实现

Modbus协议具有其高效性和可靠性的特点,在电力电子行业得到了广泛的应用.本文分析了Modbus的通信协议原理,介绍了基于ARM的无刷电机控制系统与上位机之间Modbus通信的实现,并着重阐述了通信实现的硬件平台和软件实现.     

基于 32 位 MCU 的 XLPE 生产线中 Modbus 的实现

为解决 32 位 MCU(Microcontroller Unit)与直流调速器的通讯问题,提出一种基于 Modbus 总线协议的通 讯方法以及实现过程。其中 32 位 MCU 选用 STM32F103 芯片并作为通讯主机,直流调速器选用 ETD DC790P 并作为通讯从机。该方法可以实现一主机多从机的通讯结构,实现一个 32 位 MCU 主机与多个直流调速器从 机通讯。主机通过协议发送指令给从机,从机接到指令做出动作并通过协议回应主机。实验证明,基于Modbus 协议的通讯方法能精准实现主机与多个从机的通讯以及 32 位 MCU 对电机转速转矩等控制,并且 Modbus 实现 方法具有稳定性高、抗干扰能力强、可移植性高等优点。     

SCADA系统在天然气管网中的应用

文中结合实际应用对天然气SCADA（数据采集及监控）系统的设计做了总体阐述,对SCADA系统的主要组成：数据采集、通信、监控三部分进行了介绍,描述了内嵌C语言编辑器的RTU（远程终端单元）在SCADA系统中的成功应用,解决了一般RTU中梯形图程序无法实现的与非标准协议终端设备进行通讯的问题,增强了SCADA系统的数据采集能力,通讯方面采用和手机通讯类似的无线通讯方式,比传统的电台式无线通讯更加方便、灵活,提高了通讯的可靠性。     

TDZ110A自动镗铣床控制系统研究

目的结合PLC与触摸屏,对TDZ110A普通镗铣床进行控制改进,实现镗铣床数控化.方法利用PPI协议实现了两个PLC之间的通讯、触摸屏与PLC之间的通讯,并采用自由口通讯实现STM32F103VX微处理器控制板与PLC之间的通讯,从而完成整个镗铣床控制系统的通讯.结果采用PPI协议与自由口通讯实现比较复杂的网络之间的通讯,大大简化了控制系统,使镗铣床控制系统更加先进可靠,镗铣床的控制精度达到0.001 mm,加工精度达到30~40μm.结论 PLC、交流伺服驱动系统以及触摸屏构成TDZ110A镗铣床控制系统,保证了网络之间通讯的可靠性.改进设计后的自动镗铣床提高了镗铣床加工的可靠性、加工效率和自动化能力,使该设备的性价比大幅度提高.     

Markedness and its Interpretation in Language Use

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.     

Features of Women's language

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.     

低渗透非均质砂岩油藏启动压力梯度研究

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。     

On Tragic Consciousness In The Works By Ernest Hemingway

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.     

Achieving Unusual States of Matter Under High Pressure

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-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

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-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

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     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

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     

Call for Papers

<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     

Journal of Donghua University ( English Edition) Contents of Volume 31

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