This white paper discusses how market trends, the need for increased productivity, and new legislation have accelerated the use of safety systems in industrial machinery. This TÜV-qualified FPGA design methodology is changing the paradigms of safety designs and will greatly reduce development effort, system complexity, and time to market. This allows FPGA users to design their own customized safety controllers and provides a significant competitive advantage over traditional microcontroller or ASIC-based designs. Introduction The basic motivation of deploying functional safety systems is to ensure safe operation as well as safe behavior in cases of failure. Examples of functional safety systems include train brakes, proximity sensors for hazardous areas around machines such as fast-moving robots, and distributed control systems in process automation equipment such as those used in petrochemical plants. The International Electrotechnical Commission’s standard, IEC 61508: “Functional safety of electrical/electronic/programmable electronic safety-related systems,” is understood as the standard for designing safety systems for electrical, electronic, and programmable electronic (E/E/PE) equipment. This standard was developed in the mid-1980s and has been revised several times to cover the technical advances in various industries. In addition, derivative standards have been developed for specific markets and applications that prescribe the particular requirements on functional safety systems in these industry applications. Example applications include process automation (IEC 61511), machine automation (IEC 62061), transportation (railway EN 50128), medical (IEC 62304), automotive (ISO 26262), power generation, distribution, and transportation. 图Figure 1. Local Safety System
上传时间： 2013-11-14
上传用户：zoudejile
最新的HDMI I.3（高清晰度多媒体接口1.3）标准把以前的HDMI 1.0 - 1.2标准所规定的数据传送速度提高了一倍，每对差动信号线的速度达到3.4 Gbps。由于数据传送速度这么高，要求电路板的电容小，确保信号的素质很好，这给电路板的设计带来了新的挑战。在解决这个问题，实现可靠的静电放电（ESD）保护时，这点尤其重要。在HDMI系统设计中增加ESD保护时，如果选用合适的办法，就可以把问题简化。泰科电子的ESD和过电流保护参考设计，符合3.4 GHz的HDMI 1.3规范，达到IEC 61000-4-2关于ESD保护的要求，并且可以优化电路板的空间，所有这些可以帮助设计人员减少风险。本文探讨在HDMI 1.3系统中设计ESD保护的要求和容易犯的错误。 概述 在高清晰度视频系统中增加ESD保护，提出了许多复杂而且令人为难的问题，这会增加成本，会延长产品上市的时间。人们在选择ESD保护方案时，往往是根据解决这个问题的办法实现起来是否容易。不过，最简单的办法也许不可能提供充分的ESD保护，或者在电路板上占用的空间不能让人最满意。有些时候，在开始时看上去是解决ESD保护问题的最好办法，到了后来，会发现需要使用多种电路板材来保证时基信号达到要求。在实现一个充分的静电放电保护时，往往需要在尺寸、静电放电保护的性能以及实现起来是否容易这几方面进行折衷。一直到现在仍然是这样。
上传时间： 2015-01-02
上传用户：zhuimenghuadie
微电脑型单相交流集合式电表（单相二线系统） 特点： 精确度0.25%满刻度±1位数 可同时量测与显示交流电压,電流,頻率,瓦特,(功率因數/視在功率) 交流電壓,電流,瓦特皆為真正有效值(TRMS) 交流電流,瓦特之小數點可任意設定 瓦特單位W或KW可任意設定 CT比可任意設定(1至999) 輸入與輸出絕緣耐压 2仟伏特/1分鐘( 突波測試強度4仟伏特(1.2x50us) 數位RS-485界面 (Optional) 主要规格： 精确度: 0.1% F.S.±1 digit (Frequency) 0.25% F.S.±1 digit(ACA,ACV,Watt,VA) 0.25% F.S. ±0.25o(Power Factor) (-.300~+.300) 输入负载: <0.2VA (Voltage) <0.2VA (Current) 最大过载能力: Current related input: 3 x rated continuous 10 x rated 30 sec. 25 x rated 3sec. 50 x rated 1sec. Voltage related input: maximum 2 x rated continuous 过载显示: "doFL" 显示值范围: 0~600.0V(Voltage) 0~999.9Hz(Frequency)(<20% for voltage input) 0~19999 digit adjustable(Current,Watt,VA) 取样时间: 2 cycles/sec. RS-485通讯位址: "01"-"FF" RS-485传输速度: 19200/9600/4800/2400 selective RS-485通信协议: Modbus RTU mode 温度系数: 100ppm/℃ (0-50℃) 显示幕: Red high efficiency LEDs high 10.16 mm(0.4") 参数设定方式: Touch switches 记忆型式: Non-volatile E²PROM memory 绝缘抗阻: >100Mohm with 500V DC 绝缘耐压能力: 2KVac/1 min. (input/output/power) 1600 Vdc (input/output) 突波测试: ANSI c37.90a/1974,DIN-IEC 255-4 impulse voltage 4KV(1.2x50us) 使用环境条件: 0-50℃(20 to 90% RH non-condensed) 存放环境条件: 0-70℃(20 to 90% RH non-condensed) CE认证: EN 55022:1998/A1:2000 Class A EN 61000-3-2:2000 EN 61000-3-3:1995/A1:2001 EN 55024:1998/A1:2001
上传时间： 2015-01-03
上传用户：几何公差
在强调正确性、可移植性和可维护性的基础上，对C语言的具体细节、运行库以及C语言编程风格做了完整、准确的描述。本书涵盖了传统C语言、C89、C95、C99等所有C语言版本的实现，同时讨论了C++与C语言兼容的部分。全书自上而下介绍了C语言的词法结构、预处理器、声明、类型表达式、语句、函数和运行库，是所有C语言编程人员必备的参考书。 这本畅销的权威参考手册对C语言的基本概念和运行库提供了完整的描述，同时还强调了以正确性、可移植性和可维护性为根本出发点的良好的C语言编程风格，被国外众多高校广泛采用为教材或教学参考书，本书描述了C语言各个版本的所有细节，是C语言编程人员和实现者惟一必备的参考手册。最新的第5版经过修订和更新，融入了最新C语言标准ISO IEC 9899：1999的完整描述，包括强大的语言扩展和新的函数库。
上传时间： 2014-01-21
上传用户：xz85592677
INTERNATIONAL ORGANISATION FOR STANDARDISATION ORGANISATION INTERNATIONALE DE NORMALISATION ISO/IEC JTC1/SC29/WG11 CODING OF MOVING PICTURES AND AUDIO
标签： ORGANISATION STANDARDISATION INTERNATIONALE INTERNATIONAL
上传时间： 2014-01-11
上传用户：ainimao
DIGITAL IMAGERY is pervasive in our world today. Consequently, standards for the efficient representation and interchange of digital images are essential. To date, some of the most successful still image compression standards have resulted from the ongoing work of the Joint Photographic Experts Group (JPEG). This group operates under the auspices of Joint Technical Committee 1, Subcommittee 29, Working Group 1 (JTC 1/SC 29/WG 1), a collaborative effort between the International Organization for Standardization (ISO) and International Telecommunication Union Standardization Sector (ITUT). Both the JPEG [1–3] and JPEG-LS [4–6] standards were born from the work of the JPEG committee. For the last few years, the JPEG committee has been working towards the establishment of a new standard known as JPEG 2000 (i.e., ISO/IEC 15444). The fruits of these labors are now coming to bear, as JPEG-2000 Part 1 (i.e., ISO/IEC 15444-1 [7]) has recently been approved as a new international standard.
标签： Consequently efficient pervasive standards
上传时间： 2013-12-21
上传用户：源弋弋
Draft ITU-T Recommendation and Final Draft International Standard of Joint Video Specification(ITU-T REec. H.264 | ISO/IEC 14496-10 AVC).H.264视频编码标准的中文翻译版本，由沈燕飞对原文作翻译。
标签： Draft ITU-T Recommendation International
上传时间： 2014-01-05
上传用户：来茴
Draft ITU-T Recommendation and Final Draft International Standard of Joint Video Specification(ITU-T Rec.H.264 | ISO/IEC 14496-10 AVC) H.264编码标准，主体部分是中英文对照
标签： Draft ITU-T Recommendation International
上传时间： 2015-09-28
上传用户：lunshaomo
The Scalable Video Coding(SVC) draft specification version 8 was released by Joint Video Team(JVT) on Oct,2006. JVT is formed by ISO/IEC MPEG & ITU-T VCEG.
标签： Video specification Scalable released
上传时间： 2015-10-11
上传用户：924484786
三相短路电流计算方法的探讨 吕文杰 ：利用PSS / E 程序丰富的短路电流计算功能和灵活的短路电流初值设置条件，分析了影响短路电流计算结果 的一些关键因素，对基于潮流的短路电流计算、经典计算方法和IEC 推荐方法进行了比较
上传时间： 2013-12-11
上传用户：colinal
