基于CAN总线的分布式安全报警系统

CAN总线是一种多主站局部网络 ,支持分布式控制系统或实时控制系统的通信功能 ,具有检错功能强 ,抗干扰 ,传输速率高等优点 ,广泛应用于工业控制领域。笔者以CAN总线技术为基础 ,用单片机和个人计算机组成分布式安全报警系统 ,该系统具有开放性、全分散体系结构、安装维护简单等特点。笔者介绍了该系统的总体构成及其软件和硬件设计。试验结果表明 ,该系统实现了事故现场、住户与住宅小区三者联系的安全报警功能。系统稳定性好 ,实时性强 ,报警准确。     

Work domain analysis for air traffic controller weather displays

INTRODUCTION: Adverse weather conditions have a major impact on National Airspace System (NAS) operations. They create safety hazards for pilots, constrain the usable airspace for air traffic control (ATC), and reduce the overall capacity of the NAS. A system-wide dissemination of weather information to controllers could theoretically improve safety and efficiency. PROBLEM: However, it is currently unclear what weather information would be beneficial for tactical operations. Furthermore, no previous research has empirically evaluated optimal presentation designs for ATC weather displays. Ill-designed weather displays can cause safety hazards by presenting redundant information (i.e., by increasing the cognitive load) and display clutter (e.g., by interfering with the visual extraction of traffic data). METHOD: In the present paper, we outline our use of cognitive work analysis (CWA) techniques for the assessment of weather information needs for terminal controllers. RESULTS: Specifically, we describe how the CWA modeling tools helped us reveal instances in the terminal domain where weather information is lacking or insufficiently disseminated. We used our CWA results to drive the development of weather display concepts and to set up a high-fidelity simulation capability. IMPACT ON INDUSTRY: By means of high-fidelity simulations, we can empirically evaluate controller weather information needs in order to propose weather displays for increased aircraft safety and efficiency of terminal operations.     

基于PLC的MBR小型污水处理工艺的自动控制系统设计

本设计以沈阳市某污水处理及中水回用设施的控制系统为研究背景,结合污水处理工艺,探讨以日本三菱公司的FX2N系列的PLC在采用膜生物反应器(MBR)工艺的小型污水处理设施中的应用,重点阐述了系统的硬件构成及系统软件的设计思路,具有自动/手动两种工作模式,根据气水比比值以及自吸泵占空比确定鼓风机曝气启动时间,鼓风机自动定时...