Design of Signal Lamp Filament Monitoring Alarm Instrument

To improve the reliability of the light emitting diode(LED)signal lamp filament current monitoring alarm instrument for metro systems,a new type of hot standby online monitoring apparatus was developed which is based on synchronous transmission data(STD)bus technology.In this system,a double hot standby mode can be achieved by adopting bus arbitration.In addition,to detect the effective value of alternating current which is from 0 to 200 mA in the signal lamp lighting circuit,a precision rectifier signal conditioning circuit and an isolated acquisition circuit were designed.This new type of alarm instrument has high detection accuracy and could meet the functional requirements for metro signal systems after comparing it with some industry products that were applied on the spot.

Geo-technical Instrumentation And Monitoring For Tuen Mun Station, West Railway, Hong Kong

Geo-technical instrumentation and monitoring is very important for the construction of civil works in urban area, by which the affect or even damage to the existing building and underground utilities in the working site or vicinity caused by construction activities can be predicted. During the construction of Tuen Mun station, West Railway, Hong Kong, series of Geo-technical instruments were installed and monitored in time, and the monitoring data were transferred to the Geo-technical Monitoring System in the headquarter of the Employer promptly. Meanwhile, the alarming data were responded immediately and the modified construction methods have been adopted to avoid the damage to the building and underground utility in working site to ensure the smooth construction of the station.

A review of bridge scour monitoring techniques

The high profile failure of the Malahide Viaduct in Dublin, Ireland, which is a part of the EU TEN-T network of critical transport links, was caused by foundation scour. Scour is a common soil-structure interaction problem. In light of current changes in climate, increasing frequency of flooding, coupled with the increasing magnitude of these flood events, will lead to a higher risk of bridge failure. Moni- toring scour is of paramount importance to ensure the continued safe operation of the aging bridge asset network. Most monitoring regimes are based on expensive underwater instrumentation that can often be subjected to damage during times of flooding, when scour risk is at its highest. This paper presents a critical review of existing scour monitoring equipments and methodologies with a particular focus on those using the dynamic response of the structure to indicate the existence and severity of the scour phenomenon affecting the structure. A sensitivity study on a recently developed monitoring method is also undertaken.

A new device for stress monitoring in continuously welded rails using bi-directional strain method

The technology of continuously welded rails （CWRs） is important in modern railway track structures. To measure rail stress, resistance strain gauges are preferred due to their good stability, sensitivity, and esistance to external interference. Based on the bi-directional strain method, we present a new method for measuring longitudinal rail stress using resistance strain gauges and develop a monitoring device for rail stress to realize long-term and multi-point measurement. Also relevant experimental verification and analysis are conducted. Results indicate that under various constraints the rail stress–strain values can be calculated just with the measured total longitudinal strain and total vertical strain. Considering the measurement error caused by sectional feature of sensors, we put forward a correction equation applicable to different stress conditions. Although the temperature values of the four full-bridge stress gauges can offset each other, the measurement error caused by rail flexural strain can also be eliminated to a certain extent at the same time, the nonuniform distribution of rail cross section temperature and unbalanced flexural strain still affect the measurement error. The experimental results also show that the developed rail-stress-monitoring sensor is suitable for measuring rail stress with reliable working performance.

Advances in fibre optic based geotechnical monitoring systems for underground excavations

Geotechnical stability is a major concern for the long-term safety and integrity of underground infrastructures such as tunnels, railway stations, mine shafts and hydraulic power chambers. An effective geotechnical monitoring system is able to provide adequate warning to underground personnel prior to any unexpected major geotechnical failure. This paper reviews the conventional geotechnical monitoring sensors and the emerging Fibre Optic Sensing(FOS) techniques, pointing out their unique features and major differences. Recent advances in various FOS based monitoring systems, including Brillouin time domain distributed optical sensors and fibre Bragg grating(FBG) sensors, are investigated through a critical review of the laboratory studies and field applications used for underground geotechnical monitoring. Particular emphasis is given to fibre packaging, temperature compensation, installation methods and instrumentation performance in the underground environment. A detailed discussion of the advantages and limitations of each FOS monitoring system is also presented in this paper.

A Remote Real-Time Monitoring System for Power Quality

An introduction is made to the composition, design method and engineering application of a remote real time monitoring system of power quality in substations based on internet. With virtual instrument and network technique adopted, this system is characterized by good real time property, high reliability, plentiful functions, and so on. It also can be used to monitor the load of a substation, such as electric locomotives.

Research on the Monitoring System of CNC Grinding Process Based on Acoustic Emission

Using on-line monitoring during the CNC grinding process,the hazard case such as the crushing of grinding wheel and various safety accidents could be avoided,and the optimum time for dressing and replacing grinding wheel could also be determined,and hence,the service life of the grinding wheel could be prolonged and grinding quality could be improved. To overcome the limitation of some traditional techniques in which some parameters including the grinding power and force,torque and so on were monitored,the acoustic emission (AE) technique,which provides high sensitivity and responding speed,were developed in the present paper. The mechanism of AE during grinding was reviewed. Moreover,a virtual AE monitoring system,which could monitor the grinding state under different working conditions during the grinding,has been developed based on the Virtual Instruments technique. Some experiments were also performed on the internal grinder. The results showed that the AE signals became stronger with increasing the main shaft speed and grinding depth or decreasing the distance between the AE sensor and grinding area.

New Progress in Dam Monitoring Automation

This article briefly compares the different characteristics of dam automatic monitoring and manual monitoring, introduces the advantages of the Automatic Monitoring and three modes for the development of Automatic Monitoring adopted by different countries, expounds the structural characteristics and products of every class/kind of automatic monitoring instruments for deformation, piezometry, leakage,stress-strain, and so on, points out the latest progress in capacity sensing series instruments in China. This paper discusses the three data collection pattems, Concentration, Distribution,and Assemble of automatic monitoring system and the characteristics of distribution system of dam safety automatic monitoring in different industrial control fields, gives a brief introduction to the Intelligent Distribution System of Dam Safety Monitoring (DAMS-IV), developed by Nanjing Automation Research Institute (NARI) which is suitable for different scales of projects and with excellent performances.

Ageing management strategies for instrumentation and control equipment in NPPs

This paper aims to explain main ageing stressors and effects on instrumentation and control (I&C) components followed by ageing management strategies through developed design such as using freewheeling diode to eliminate relays contact ageing due to inductive loads, or through traditional practices and new online monitoring where I&C components can be checked and assessed remotely while the plant is operating. It also includes some recommendations for obsolescence management for special I&C components like microcontrollers and programmable logic controllers (PLCs).

Communication Technology and Application of Seismic Precursor Network Instrument

In this paper, the communication technology of seismic precursor network instrument is introduced, including instruction format and returned information format of instrument login, status information acquisition, and current measured data acquisition. The remote monitoring alarm software is based on this technology, and also introduced that the structure of monitoring information table, abnormal alarm index, and monitoring strategy. The application of the software raises instrument running rate and observation data quality.

高土石坝变形监测研究进展

土石坝变形协调控制对保证其全生命期安全至关重要,准确可靠的变形监测是评估大坝变形性态、进行变形控制的基础。我国土石坝设计水平与建造技术已达到世界领先水平,其建设高度已迈入300 m级,安全监测技术也得到显著提升。本文总结了土石坝变形监测技术的发展与实践,介绍了分布式光纤传感、管道监测系统、GNSS/北斗、InSAR等新型内外观变形监测技术的工作原理、应用情况、技术优势和局限性,并简述了监测资料整编工作的相关进展。最近建成和在建的几座高土石坝已初步呈现了多技术协同、测点密集化等新态势,可全方位感知土石坝变形,为大坝安全评估提供了良好的数据基础。未来需进一步提升监测仪器可靠性与寿命,研发适用于超深厚覆盖层巨型土石坝的监测技术和仪器,研究海量多源异构监测数据治理理论与方法,全面提升复杂条件下的土石坝安全监测能力和数据治理水平。

基于微处理器和多通信方式的大坝变形智能监测仪器的设计与实现

变形监测作为大坝安全状态感知的重要手段,具有测值直观、能全面反映大坝安全状态等特点,对保障大坝长期安全稳定运行具有重要的意义。目前大坝水平位移自动化监测主要使用引张线法、真空激光准直法及垂线法。尽管CCD垂线坐标仪已在大坝工程实践中广泛应用,可该仪器存在不支持现场配置、现场实时数据读取等不足,且无直接远程交互功能,需要接入其他采集装置或转接设备才能进行远程通信。本文设计的智能式CCD垂线坐标仪运用微处理器及以太网接口,不需要接入其他采集设备,可直接接入软件系统,解决了仪器集成复杂、传统通信方式不稳定等问题;并运用蓝牙通信和智能手机APP,解决了现场参数配置、实时采集显示的问题;提出了一种反馈式自适应调光技术,提高了仪器的自适应性和稳定性。

Design of Vibration Monitoring System of CNC Machine

CNC machine have a fast development and is widely used in China. Generally, CNC machine tool, includs CNC lathes and CNC milling machine. CNC machine tool is a necessary tool for machining. It plays an important role in the mechanical design and machining fields. CNC machine tool is mainly composed of two parts of the machine body and the computer control system. Mechanical equipment failures usually related information such as vibration, sound, pressure, temperature performance. CNC machine tool vibration monitoring system with piezoelectric accelerometer, the eddy current displacement sensor, signal amplifier, signal conditioning modules. We can take an advantage of the CNC machine tool vibration monitoring system for vibration monitoring and fault diagnosis of CNC machine tools.

广东地震地下流体监测网质量与效能分析

依据流体学科相关评价标准,从广东地下流体观测网观测环境、观测仪器、观测质量和预测应用方面着手,结合地下流体学科台网中心提供的台站网运行监控和质量监控情况,对地下流体观测网每个观测站的观测环境、仪器的运行情况、观测仪器产出的数据的质量及其预测应用情况进行了评估。结果显示,观测站观测环境满足二类台站居多;观测数据运行率为优秀者占比:水位、水温和氡各为77.8%、63.6%和100.0%;流体仪器数据完整率全部为优秀;预测应用效能井水位和氡均为良好,水温有88.9%为良好。通过评估,较全面地分析了广东地下流体观测网存在的问题,并针对存在的不足提出改进措施及建议。

基于GRU的仪表着陆系统故障预测方法研究

故障预测技术在保障仪表着陆系统的可靠运行、提高空管效能等方面具有重要应用价值。结合仪表着陆系统运行特征和实际运行维护工作,提出一种基于GRU的仪表着陆系统故障预测方法。以航向信标为研究对象,在分析其监控参数与设备运行状态之间的关系后,将监控参数作为故障特征参数;根据监控参数时间步长、时变性特征显著的特点,采用GRU预测监控参数的未来变化趋势;根据监控参数的隶属函数计算出参数未来时刻可能发生“故障”的概率,实现对航向信标故障的预测。结果表明:基于GRU的仪表着陆系统预测方法的相对预测精度在95%以上。

基于内存保护键值的细粒度访存监控

基于内存保护键值硬件扩展,提出了一种轻量化且细粒度的页保护机制。突破了传统页保护方法仅支持页粒度访存监控的技术局限,实现了能够拦截每个访存操作的细粒度页保护机制。充分利用内存保护键值提供的用户态线程局部页访问权限控制,性能开销相比传统页保护的降低了30%以上。通过融合细粒度页保护与编译插桩,弥补了传统编译插桩方法无法覆盖程序中不可重编译部分的局限性。

The W-11-4A Platform Comprehensive Strength Monitoring System

A comprehensive strength monitoring system used on a fixed jacket platform is presented in this paper. The long-term monitoring of W-11-4A platform achieved. Structural responses (strain and acceleration) at selected locations, as well as associated environmental parameters, have been obtained. The emphasis of the paper is placed on the system design, and the instrumentation and operation methodology employed in the monitoring of the structural responses. The performance of the system and the characteristic results obtained during its 13-month operation are also summarized.

硅半导体辐射探测仪表国产化研制及性能研究

γ剂量率辐射监测装置是核电厂内部以及周围环境中辐射监测的重要设备,可以实时监测工作场所内或工艺设备附近辐射场水平的变化,能够为辐射防护最优化和辐射安全评价提供依据。随着反应堆的小体积高安全性能的发展趋势,辐射监测方面也对小体积宽量程高可靠性的仪表提出必要需求。硅半导体探测器工作电压为低压,设备寿命长、性能稳定,比电离室或G-M计数管在γ剂量率监测方面更加有优势。本文研制的硅半导体辐射探测器及监测仪表主要由探测单元、就地处理显示单元和接线箱组成,具有体积小、宽量程等特点。本文主要介绍研制仪表的组成及探测单元设计并针对其核心性能辐射特性开展相关测试研究,评估了辐射特性结果,为实现此设备的工程应用奠定重要基础。