浅谈化工装置中仪表线路的工程设计

针对化工装置仪表线路所包含的仪表电缆、防爆电缆接头、现场仪表接线箱等组成部分的分类及选型进行了阐述.对仪表线路不同的敷设方式之间的优缺点进行了剖析,提出了电缆槽架空敷设方式是目前在化工装置中比较理想的敷设方式.根据规范要求并结合工程实际,提出了现今比较成熟可靠的仪表线路工程设计方案,并提出了仪表线路工程设计中的注意事项...     

自动化仪表发展趋势探讨

在仪表行业迅猛发展的今天,各式各样的仪表层出不穷,琳琅满目,生产中使用的仪表越来越先进,仪表展示会上展出的仪表更是百花齐放,百家争鸣.我国仪表行业的六大基地、三大集团、一个自控总公司、十个研究所努力开发,新式仪表相继问世,加上先进仪表引进,使整个自动化仪表的发展出现了生机勃勃的景象.但总观全局,自动化仪表主要有如下五种发展趋势.     

基于MSP430F147的高精度压力变送器数显仪表

介绍一种以MSP430F147为主控芯片的压力变送器数显仪表系统,详细阐述了系统的硬件设计架构,并重点讨论了其温度补偿方案.该仪表通过220 V交流供电,可实现一键切换测量单位功能,并可对外提供独立的±15 V电源,供压力变送器或其他一次仪表使用.实践证明:该仪表精度高、温度漂移低、稳定性强,可作为高精度电测仪表广泛应用于工业、科研、医疗等众多领域.     

船用仪表计量保障的分析与思考

本文从船用仪表对船舶和人员安全角度,阐述了开展船用仪表计量保障的必要性,并对船用仪表计量保障现状进行了分析,描述当前船用仪表计量保障存在的问题.最后,针对存在的问题,结合个人思考,在现行船舶船用仪表计量保障方面提出了改进的意见建议.在未来船舶船用仪表计量保障方面,结合船舶未来智能化发展趋势,对未来船用仪表计量保障进行了...     

自动化仪表的故障维护策略分析

信息化时代到来后,市场上出现了越来越多的自动化设备和仪表,这些设备、仪表中充分集成了自动化、信息等多种技术,兼具多方面的功能.现阶段的生产领域,自动化仪表已成为关键性的要素,但因为仪表构成复杂、使用环境的复杂性,导致自动化仪表面临着故障频发的问题,为保障自动化仪表的功能和作用实现,故障维护和处理已然成为了重点性的工作....     

基于DSP2812的Profibus-DP通信接口设计

Profibus现场总线随着其卓越的技术性能的发展,在全世界范围内拥有了越来越多的用户群.工业现场的电力仪表正在朝着智能化、模块化、网络化的方向发展,提出了一种新的电力仪表Profibus-DP通信接口的设计方法,结合硬件平台给出了软件实现.实验证明该电力仪表的Profibus-DP通信实时、稳定、可靠.     

基于遗传算法的智能仪表设计专家系统

为解决遗传算法存在的早熟、收敛全局最优解难题,提出适应度标定问题;定义相似度概念,剔除相似性个体.提出了CPU模板概念,解决了外围模块与CPU的耦合关系,提出了仪表组成模块的性能参数与仪表的性能参数之间的映射关系.改进遗传算法解决了传统的遗传算法存在问题,并且解决了穷举法进行模块组合的效率问题,基于此算法的推理机制能够做到设计新仪表,并且新仪表能基本符合用户要求.     

使用CNN-SVR的汽车组合仪表组装质量预测方法

汽车组合仪表组装过程质检时间长、效率低,因此提出卷积神经网络与支持向量回归相结合的汽车组合仪表组装质量预测方法.结合仪表组装工艺,将卷积神经网络提取的生产数据特征作为支持向量回归的输入,对表征仪表质量的指针偏转角度做出预测.通过车间质检系统获取了仪表原始生产数据,对不同质检情况下的指针偏转角度进行了预测;结果表明所提方...     

2011年日本过程自动化仪表生产概况——兼析2007～2011年生产数据

日本经济产业省的《机械统计月报》载有日本50人以上自动化仪表企业的统计数据,以前分为过程自动化仪表(PA仪表)和工厂自动化仪表(FA仪表)两部分,PA仪表年产量和年产值均占总量的绝对多数,约97％左右,201 1年取消了FA仪表部分,仅列出PA仪表数据.本文拟对201 1年日本PA仪表生产数据进行汇总、整理和介绍,并对2007～2011年生产数据做些浅析. 1 日本PA仪表统计分类 日本PA仪表在该统计资料上分为5大类,即过程发信器、过程接收仪、过程分析仪、过程监控系统和其他过程测量仪表.有的大类又细分若干小类.     

仪表式车床的横系列模块化设计

对仪表式车床从功能域和结构域两个方面进行了分解.确定了仪表式车床的模块划分原则.利用设计结构矩阵建立了功能元与结构元之间的映射关系,并对各种映射关系是否适合划分模块做了描述.根据功能元与结构元之间的映射关系以及仪表式车床实际的结构特点,划分出了比较通用的模块划分.利用基本功能模块和附加功能模块的不同组合方式,确定了多种横系列的模块化仪表式车床.最后,对仪表式车床的横系列模块化设计的优点进行了概括.     

基于相关匹配的QR码识别方法

QR码图像识别是QR码应用中的关键技术.Hough变换、曲面拟合去背景、控制点变换等方法为QR码识别过程中图像预处理的基本方法,针对图像预处理后图像识别率低的缺点,提出了一种基于相关匹配法的QR码识别方法.基于曲面拟合的改进自适应阈值法分割图像.采用Hough变换和控制点变换方法校正图像的几何失真变形.利用模板对QR码进行相关匹配,对相干系数阈值处理得出取样网格.实验表明,本文算法能有效提高QR码识别效率和效果.     

Water meter pointer reading recognition method based on target-key point detection

With the rapid development of video image technology and fifth-generation mobile network technology, the automatic verification of mechanical water meters has become an increasingly important topic in smart cities. Although much research has been done on this subject, the efficiency and accuracy of existing water meter pointer reading technology can still be improved. This paper proposes a new water meter pointer reading recognition method based on target-key point detection. Our method consists of a target detection module and a key point detection module. The target detection module uses a modified YOLOv4-Tiny network to detect and classify the areas where the dials and pointers are located in water meter images with distinct characteristics. The key point detection module is used to detect the key point of the pointer image. In this module, the structure of the RFB-Net network is improved to introduce multiple layers of low-level feature information, therefore, it can make full use of the information between multi-scale feature layers for key point detection. In addition to, aiming at the problem of dial rotation, a method of establishing a right-angle coordinate system based on key point is proposed to realize pointer reading. The whole method proposed in this paper is compared to the Hough transform feature matching algorithm and traditional machine learning algorithms through experiments which test the detection and recognition of the water meter dial, pointer and key points. The experiment results show that the missed detection rate of the model in this paper is 1.88% and 1.07% for the dial region and the pointer region, respectively. And the accuracy rate reaches 98.68%, the average processing time per image is 0.37 s. This implies that the water meter inspection task is completed quickly and accurately with strong robustness. Thanks to the lightweight algorithm of our approach, the model can also be fully automated and easily deployed on mobile devices.     

基于视频图像的工业仪表高速自动识别

针对工业现场高速变化的灯板仪表全自动检测的问题,提出了一种基于图像识别的检测方法。本方法采用高速工业相机获取仪表视频图像,并采用数字图像处理技术,对单帧图像用OSTU算法进行二值化分割,运用邻域平均法进行平滑处理,通过闭运算以完成去噪,运用Hough变换以实现对灯的逐一定位,并用灰度检测法对灯状态进行判读,最后保存视频。研究结果表明,该算法可靠有效,系统能够高速准确地应对仪表位置的变化,为进一步的一般化视频检测奠定了基础。     

近净形成形中基于知识的产品多视CAD模型自动转换研究

计算机辅助近净形成形中由产品 CAD模型生成各应用模型通常需要大量的知识和经验 ,耗时且易出错。实现模型的自动转化不仅能提高设计效率 ,改善设计质量 ,同时可保证设计结果的一致性 ,因而具有十分重要的工程应用背景。本文讨论了各应用模型和产品模型之间的关系 ,指出应用模型由产品模型加减若干特征生成。在此基础上提出了基于 KBE技术及特征识别、特征建模的模型自动转换的实施框架     

基于特征降维和神经网络的电能表内异物声音自动识别

电能表是国家强制检定的电能计量工具,其计量的精确性影响着千家万户的利益。传统的人工检测方式不仅效率低而且检测结果不稳定。随着声学检测技术的日趋成熟,采用声学检测的方式来检测电能表内的异物已成为实现工厂自动化的大势所趋。针对现有半自动的人工检测电能表异物方式,提出一种基于特征降维和神经网络的电能表内的异物声音自动识别方法。该方法充分利用声音的时、频域特征系数和倒谱系数,先对声音信号进行通道转换、预处理和数字降噪,再对声音信号进行时、频域和倒谱分析,并同时提取其短时特征系数及改进后MFCC系数。将声音特征通过PCA降维后输入基于Adaboost算法聚类后BP神经网络分类识别,并与传统的BP神经网络分类进行比较,证明了该方法的有效性。这里给出了电能表异物自动识别技术实现的具体步骤,并通过MATLAB仿真实验证明了该方法的有效性,BP神经网络的平均识别率较高,可达到95%以上,并且计算复杂度小易于实现。     

A flexible method for multi-view point clouds alignment of small-size object

Alignment is a key step of the point cloud processing. We propose a flexible, easy-implemented, low-cost alignment method for multi-view point clouds of small-size objects (≦50 cm). The method is based on the idea of rotating measurement, firstly more than three pieces of point clouds of cylinder calibration pattern are used for calibrating the center axis of a single-axis turntable in the scanner’s coordinate system, so the rigid relationship of the turntable and scanner can be obtained. Then the rotation matrix can be calculated using the known angle parameter of the turntable, and finally an arbitrary view of point cloud can be easily transformed into a unified coordinate system by the rotation transformation. Our method does not require overlapping feature or co-markers constraint between point clouds, and only the rigid relationship between the scanner and the turntable and rotate angle need to be known. More importantly, the calibration of the turntable is flexible and low-cost: (1) the calibration pattern can be a common cylinder objects (such as cup, paper tube, caddy, water pipe, etc.), (2) the turntable and the alignment method can be integrated with variety 3-D scanners. The result of experiment has demonstrated the efficiency and automatic characteristic of the alignment method compared with other two convention methods.     

基于仿射变换和均值像素法的环状编码点鲁棒识别

在近景工业摄影测量中,针对环状编码点精确定位和准确识别的要求,提出了一种鲁棒性识别算法。该算法在对目标图像预处理后,首先根据边缘滤波准则初步定位编码点,并将含编码带的特征区域分割出来。然后,利用最小二乘法对特征区域进行仿射变换,将经透视投影退化的椭圆映射成规则圆形。最后,采用均值像素法获取环状编码点的解码值,进一步提高编码点的抗噪性。大量实验结果表明:该方法在对编码点的中心定位达到亚像素级别的同时,改善了算法对识别角度的鲁棒性,在识别角度为70°时,正确识别率仍可达97.9%,在实际复杂场景中具有较好的实用价值。     

A robust and automatic recognition system of analog instruments in power system by using computer vision

It is a puzzling issue found in the field of Supervisory Control and Data Acquisition (SCADA) to read automatically the indication of analog measuring instruments, which collects many states of power system equipment. To address this problem, a lot of approaches based on computer vision have been proposed for the automatic reading of the analog measuring instruments indication. However, most the proposed systems are sensitive to brightness. Moreover, since the camera angle must be vertical, the robustness of the approaches cannot meet application requirements. In this paper, the proposed recognition system uses a novel automatic reading approach, which can automatically read the indication of analog measuring instruments at various brightness levels and camera angles. It is an integrated application of Multi-Scale Retinex with color restoration at different brightness levels, Perspective Transform to get the front view of image taken from arbitrary camera angle, and Hough Transform to determine the pointer position. The test results verify the good robustness of the recognition system to the brightness and camera angle.     

Automatic transformation between water level meter measurement data and altitude on the large-scale physical model

The water level is one of the most important physical parameters of the physical model experiment. A large-scale physical model usually has many water level meters, It is an important basis for the accurate simulation of the water level to determine the transformation relationship between those level meters readings and the altitude in the prototype. Based on collimated characteristics of laser and image processing by binarization of gray image and character segmentation, an automatic transformation system was developed to improve transformation accuracy. The main idea is to use laser scanner to build a reference plane, then light illuminates the water level meter, so that the CCD on the top of the water level meter could gather the laser beam and convert light intensity to image signals. With further image processing, such as threshold transformation, the system can get the coordinate of laser center. Due to the fixed relationship between the coordinate and the water level meter measurement data, then the system can found transformation relation between water level meter and altitude automatically. Experiments show that comparing with the manual calibration, relative error of automatic calibration water level meter altitude conversion decreased from ±1.34% to ±0.19%.     

变电站巡检机器人的数字仪表自动识别技术研究

针对变电站巡检机器人数字仪表识别算法准确度不高的问题,本文提出了一种基于样本匹配算法的数字仪表读数识别算法。该算法在使用局部最大类间方差的高阶统计和阈值对仪表板上的显示区域进行定位的基础上,最后根据数字仪表显示区域和数字位置相对固定的特征采用样本匹配算法实现对数字仪表的自动读数。实验结果表明,该方法简单、高效,可有效地应用于变电站自动检测机器人的室内仪表读数自动识别任务。