无线监测系统在电站顺序控制系统中的应用

利用无线网络在工业应用中具有的优势,在电站化学水处理车间内建立基于ZigBee的无线监测系统采集现场设备的状态。设计系统架构、开发基站和无线终端模块,并针对现场设备的分布情况,组建无线网络,将采集到的设备状态上传到运行员站。同时,为减少对现场已有PLC控制系统的影响,在安装无线监测系统的过程中,充分考虑两套系统间的隔离问题,最终实现两套系统的并行运行。通过两套系统运行结果的对比,验证无线监测系统的可靠性。     

Wireless Monitoring System for Chemical Water Treatment in Power Plant

利用无线网络在工业应用中具有的优势,在电站化学水处理车间内建立基于ZigBee的无线监测系统采集现场设备的状态.设计系统架构、开发基站和无线终端模块,并针对现场设备的分布情况,组建无线网络,将采集到的设备状态上传到运行员站.同时,为减少对现场已有PLC控制系统的影响,在安装无线监测系统的过程中,充分考虑两套系统间的隔离问题,最终实现两套系统的并行运行.通过两套系统运行结果的对比,验证无线监测系统的可靠性.     

SCADA系统中开放式通信模型的设计及应用

针对工业测控系统中现场设备类型众多、各厂家标准不统一、设备难与网络互连的情况 ,提出一种开放式通信网络的设计方案 ,其模块化的框架结构便于实现异构环境中不同RTU间的通信。结合某变电站SCADA系统 ,给出了基于Modbus和CAN协议的多个RTU与通信网络的通信机制。实际运行结果表明 ,该通信系统具有很好的可靠性和实时性     

WIA-PA工业无线网络多信道MAC协议设计

WIA-PA是我国制定的用于过程自动化的工业无线网络协议标准,基于传统单信道和信道竞争的MAC协议不能满足工业无线网络对通信抗干扰、实时性和可靠性的较高要求。提出基于WIA-PA分簇网络的多信道TDMA MAC协议即TMCC-MAC。该协议改进了IEEE 802.15.4超帧结构,并主要研究了WIA-PA网络簇间通信信道和时隙分配问题。实验表明该协议同时具有低功耗、多信道和时分通信的优点,能较好地满足工业无线通信要求。     

交换式以太网用于现场实时通信的研究

基于网络演算理论对FCFS调度和IEEE802.1P调度的交换式以太网实时性进行了分析,根据用于过程控制和运动控制领域的工业以太网实时要求及特点对交换式以太网在工业实时性满足方面进行了具体说明.对于用于过程控制现场的工业以太网并不需要对抖动进行严格控制,实时要求没有用于离散控制工业以太网的苛刻,同时商用网络软硬件技术还在不断发展,可以探索基于交换式以太网的新技术进行过程工业实时通信以太网的构建.     

基于UWB的工业控制网络体系结构研究

鉴于现阶段无线技术在工业控制系统应用中存在的问题,将UWB(Ultra Wideband)技术引入到工业控制网络中.提出了基于UWB的双频二级工业控制网络体系结构.同时,在此体系结构基础上设计了相应的通信模型和设备模型,并对此方案进行了分析和评价.该方案在系统级上部分缓解了无线技术在工业环境中实时性和可靠性先天不足的问题.     

基于WIA工业无线网关的设计

基于WIA的工业无线网关,实现WIA无线网络和以太网有线网络之间的相互通信,将网络监测、终端设备控制和以太网有效的连接在一起,为WIA传感器网络提供了一个远程网络控制平台,完成WIA无线网络和以太网之间数据的透明传输和协议转换,井给出了WIA的工业无线网关硬件设计和一种WIA网络与以太网网络协议转换的方法.     

InTouch在无线超滤监控系统中的应用

设计了基于西门子S7-300和组态软件InTouch的上位机监控系统,同时为了便于评估新的基于无线传感器网络的控制系统与传统工业网络控制系统的优劣,使用FSGateWay构建OPC通信平台使两上位机通信获取所需数据,并实现历史数据的存储。经数据分析证实了无线传感器网络在控制系统中信息传输的可靠性。     

基于PDA的控制系统无线移动监控软件开发

基于WiFi无线网络和PDA设备,在常规DCS中开发了基于Windows Mobile的手持式无线移动监控软件。结合现场设备调校、数据移动监控等应用需求,设计了符合控制系统网络协议和基于无线通讯的WindowsMobile软件结构,开发了基于PDA手持式设备的各种实时监控功能,如数据记录、棒状显示、过程趋势、流程图等。该解决方案在国产WebField ECS-100控制系统上进行了应用测试,结果表明具有较好的实时性和可用性,为现场工程师进行系统调试提供了便利,有效地提高工业现场调试与维护的效率。     

InTouch Application in Ultrafiltration Wireless Monitoring System

设计了基于西门子S7-300和组态软件InTouch的上位机监控系统,同时为了便于评估新的基于无线传感器网络的控制系统与传统工业网络控制系统的优劣,使用FSGateWay构建OPC通信平台使两上位机通信获取所需数据,并实现历史数据的存储.经数据分析证实了无线传感器网络在控制系统中信息传输的可靠性.     

基于令牌的以太网实时调度方法研究

通过对传统商用以太网优缺点的分析,指出了以太网在工业界应用的优势以及在实时控制网络中的致命弱点.在此基础上提出了基于令牌的以太网实时调度方法,来改进传统基于CSMA/CD介质访问控制机制的实时性能.     

A two-tier architecture for networked process control

Traditionally, process control systems utilize dedicated, point-to-point wired communication links using a small number of sensors and actuators to regulate appropriate process variables at desired values. While this paradigm to process control has been successful, chemical plant operation could substantially benefit from an efficient integration of the existing, point-to-point control networks (wired connections from each actuator/sensor to the control system using dedicated local area networks) with additional networked (wired or wireless) actuator/sensor devices. However, augmenting existing control networks with real-time wired/wireless sensor and actuator networks challenges many of the assumptions made in the development of traditional process control methods dealing with dynamical systems linked through ideal channels with flawless, continuous communication. In the context of control systems which utilize networked sensors and actuators, key issues that need to be carefully handled at the control system design level include data losses due to field interference and time delays due to network traffic. Motivated by the above technological advances and the lack of methods to design control systems that utilize hybrid communication networks, in the present work, we present a novel two-tier control architecture for networked process control problems that involve nonlinear processes and heterogeneous measurements consisting of continuous measurements and asynchronous, delayed measurements. This class of control problems arises naturally when nonlinear processes are controlled via control systems based on hybrid communication networks (i.e., point-to-point wired links integrated with networked wired/wireless communication) or utilizing multiple heterogeneous measurements (e.g., temperature measurements which can be taken to be continuous and species concentration measurements which are fed to the control system at asynchronous time instants and frequently involve delays). While point-to-point wired links are very reliable, the presence of a shared communication network in the closed-loop system introduces additional delays and data losses and these issues should be handled at the controller design level. In the two-tier control architecture presented in this work, a lower-tier control system, which relies on point-to-point communication and continuous measurements, is first designed to stabilize the closed-loop system, and an upper-tier networked control system is subsequently designed, using Lyapunov-based model predictive control theory, to profit from both the continuous and the asynchronous, delayed measurements as well as from additional networked control actuators to improve the closed-loop system performance. The proposed two-tier control architecture preserves the stability properties of the lower-tier controller while improving the closed-loop performance. The applicability and effectiveness of the proposed control method is demonstrated using two chemical process examples.     

基于ZigBee的大体积混凝土桥墩测温系统的设计

针对大体积混凝土传统测温方式存在的排线复杂、扩充性欠佳、人工读数易产生误差以及无法实时监测混凝土内部温度变化等问题,提出了一套基于ZigBee技术的无线测温解决方案。此方案中下位机由单片机CC2530构成多点温度监测系统,数据传输利用主从方式的ZigBee无线传感网络,上位机用LabVIEW软件编制监控显示界面,实时监控混凝土的温度。该系统使得监测点温度的实时性和可靠性得到了大幅提高,保证了施工后混凝土的安全可靠。     

MODEL PREDICTIVE CONTROL (MPC) AND ITS CURRENT ISSUES IN CHEMICAL ENGINEERING

Model predictive control (MPC) is one of the main process control techniques explored in the recent past; it is the amalgamation of different technologies used to predict future control action and future control trajectories knowing the current input and output variables and the future control signals. It can be said that the MPC scheme is based on the explicit use of a process model and process measurements to generate values for process input as a solution of an on-line (real-time) optimization problem to predict future process behavior. There have been a number of contributions in the field of nonlinear model–based predictive control dealing with issues like stability, efficient computation, optimization, constraints, and others. New developments in nonlinear MPC (NMPC) approaches come from resolving various issues, from faster optimization methods to different process models. This article specifically deals with chemical engineering systems ranging from reactors to distillation columns where MPC plays a role in the enhancement of the systems’ performance.     

恒压供水变频器的嵌入式状态监测系统设计

针对目前被广泛用于恒压供水的工业变频器．设计了一种基于ARM9芯片和嵌入式Linux操作系统的变频器状态监测系统。该监控系统具有良好的可靠性和交互性,能够实现变频器状态的实时监控,并且便于扩展实现数据存储及无线通信．     

半导体加工用金刚石工具现状

总结分析了国内半导体加工用金刚石工具的发展现状.指出了国产与进口半导体加工用金刚石工具的差距,分析了产生差距的主要原因.认为需要国内企业从人员、设备、原料、环境、工艺等多个角度系统性提高产品质量和稳定性,也需要加强半导体产业上下游企业的沟通、配合,加强产学研合作,逐步提高我国半导体产业金刚石工具的整体技术水平,突破半导...     

基于铜电解槽电流分布估计的烧板故障诊断

铜电解过程中,为了实现阴极棒“烧板”故障的自动诊断和电流分布的实时监测。提出依据红外成像原理,采用红外相机拍摄铜电解槽槽面图像,提取处理后图像阴极棒部位灰度值,结合现场试验建立灰度值与物体表面温度的数学模型,进而求出阴极棒表面温度。其次,应用偏最小二乘法(PLS)分区建立阴极棒表面温度与电流之间的数学模型,整合后得出阴极棒中电流的平方值与阴极棒表面温度、阴极棒坐标点和环境温度为拟线性关系。依据模型导出的阴极棒电流与现场实测电流对比表明:该方法能较准确地测量阴极棒中电流,实现了铜电解过程阴极棒中电流分布的实时监测。此外,能准确自动诊断出发生“烧板”故障的阴极棒,通过阴极棒中电流的监控也能对“烧板”故障进行预测,实现了“烧板”故障的自动诊断。从而降低了阴极棒“烧板”故障的发生,为企业带来了良好的经济效益。     

基于无线传感器网络的罗茨风机温度监测节点的设计

根据水泥工业中大量使用的罗茨风机对温度监测的需求,提出了一种基于无线传感器网络的温度监测节点的设计方法并实现了数据的路由,使传感器采集的温度数据能够传输至协调器节点并由上位机进行处理,从而实现了多点温度的在线监测。此设计中把降低节点功耗作为最为关键的性能要求,选择器件时,在保证运行速度的前提下,尽可能选用功耗低的器件来完成无线传感器网络传感器节点的硬件设计和制作,对于传感器输出可能出现的尖峰,则采用了一种改进的数字滤波算法进行处理,因而取得了高可靠性和低能耗两者的平衡。