【英文标准名称】:Industrialcommunicationnetworks-Fieldbusspecifications-Data-linklayerservicedefinition-Type18elements
【原文标准名称】:工业通信网络.现场总线规范.数据链路层服务定义.类型18要素
【标准号】:BSEN61158-3-18-2008
【标准状态】:现行
【国别】:英国
【发布日期】:2009-01-31
【实施或试行日期】:
【发布单位】:英国标准学会(GB-BSI)
【起草单位】:BSI
【标准类型】:()
【标准水平】:()
【中文主题词】:总线系统;总线;总线(数据加工);总线(数据处理);电路网络;传播学;通讯;通信;控制设备;控制系统;控制工艺学;数据通信;数据链层;数据连接系统;数据处理;数据服务;数据设备;数据传送;定义;耐久性;定义(术语);数字的;数字数据;数字工程;电子数据处理(EDP);EDP;电子数据处理;电气工程;电子仪器;电子系统;英语;字段总线;现场总线;制导系统;工业的;工业设施;信息交换;信息处理;信息技术;界面;接口;接口(数据处理);链路层;开放系统互连;开放系统互连(OSI);OSI;开放系统互连;过程控制;过程控制工程;过程控制系统;信号;规范;规范(验收);传输媒质
【英文主题词】:Bussystems;Buses(dataprocessing);Circuitnetworks;Communication;Controlequipment;Controlsystems;Controltechnology;Datacommunication;Datalinklayers;Datalinksystem;Dataprocessing;Dataservices;Datatransfer;Definitions;Digital;Digitaldata;Digitalengineering;EDP;Electricalengineering;Electronicinstruments;Electronicsystems;Englishlanguage;Fieldbus;Guidancesystems;Industrial;Industrialfacilities;Informationinterchange;Informationprocessing;Informationtechnology;Interfaces;Interfaces(dataprocessing);Linklayers;Opensystemsinterconnection;OSI;Processcontrol;Processcontrolengineering;Processcontrolsystems;Signals;Specification;Specification(approval);Transmissionmedia
【摘要】:1.1OverviewThisstandardprovidescommonelementsforbasictime-criticalandnon-time-criticalmessagingcommunicationsbetweendevicesinanautomationenvironmentandmaterialspecifictoType18fieldbus.Theterm“time-critical”isusedtorepresentthepresenceofatime-window,withinwhichoneormorespecifiedactionsarerequiredtobecompletedwithsomedefinedlevelofcertainty.Failuretocompletespecifiedactionswithinthetimewindowrisksfailureoftheapplicationsrequestingtheactions,withattendantrisktoequipment,plantandpossiblyhumanlife.ThisstandarddefinesinanabstractwaytheexternallyvisibleserviceprovidedbytheType18fieldbusdata-linklayerintermsofa)theprimitiveactionsandeventsoftheservice;b)theparametersassociatedwitheachprimitiveactionandevent,andtheformwhichtheytake;andc)theinterrelationshipbetweentheseactionsandevents,andtheirvalidsequences.Thisstandarddefinestheservicesprovidedto?theType18fieldbusapplicationlayerattheboundarybetweentheapplicationanddatalinklayersofthefieldbusreferencemodel,and?systemmanagementattheboundarybetweenthedata-linklayerandsystemsmanagementofthefieldbusreferencemodel.1.2SpecificationsTheprincipalobjectiveofthisstandardistospecifythecharacteristicsofconceptualdata-linklayerservicessuitablefortime-criticalcommunications,andthussupplementtheOSIBasicReferenceModelinguidingthedevelopmentofdata-linkprotocolsfortime-criticalcommunications.Asecondaryobjectiveistoprovidemigrationpathsfrompreviously-existingindustrialcommunicationsprotocols.ThisspecificationmaybeusedasthebasisforformalDL-Programming-Interfaces.Nevertheless,itisnotaformalprogramminginterface,andanysuchinterfacewillneedtoaddressimplementationissuesnotcoveredbythisspecification,including:a)thesizesandoctetorderingofvariousmulti-octetserviceparameters,andb)thecorrelationofpairedrequestandconfirm,orindicationandresponse,primitives.1.3ConformanceThisstandarddoesnotspecifyindividualimplementationsorproducts,nordotheyconstraintheimplementationsofdata-linkentitieswithinindustrialautomationsystems.Thereisnoconformanceofequipmenttothisdata-linklayerservicedefinitionstandard.Instead,conformanceisachievedthroughimplementationofthecorrespondingdata-linkprotocolthatfulfillstheType18data-linklayerservicesdefinedinthisstandard.
【中国标准分类号】:M11
【国际标准分类号】:
【页数】:28P.;A4
【正文语种】:英语


【英文标准名称】:InformationSystems-OpticalCharacterRecognition(OCR)-MatrixCharacterSetsforOCR-MA
【原文标准名称】:信息系统.光学字符识别(OCR).OCR-MA矩阵字符集
【标准号】:ANSIX3.111-1986
【标准状态】:现行
【国别】:美国
【发布日期】:1986
【实施或试行日期】:
【发布单位】:美国国家标准学会(US-ANSI)
【起草单位】:ANSI
【标准类型】:()
【标准水平】:()
【中文主题词】:情报系统;字符集;光学字符识别
【英文主题词】:charactersets;informationsystems;opticalcharacterrecognition
【摘要】:DescribesthematrixofdotplacementandsizelimitsforOCR-MAalphanumericcharactersandsymbolsforopticalcharacterrecognition(OCR)systems.
【中国标准分类号】:L71
【国际标准分类号】:35_040
【页数】:33P.;A4
【正文语种】:英语