基本信息
标准名称: | 余甘子类树皮 |
英文名称: | Emblic leafflowers bark |
中标分类: |
农业、林业 >>
林业 >>
林产化工原料 |
替代情况: | 原标准号GB 7645-1987;被LY/T 1324-2012代替 |
发布日期: | 1987-03-05 |
实施日期: | 1987-10-01 |
首发日期: | |
作废日期: | 2012-07-01 |
出版日期: | |
页数: | 2页 |
适用范围
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前言
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目录
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引用标准
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所属分类: 农业 林业 林业 林产化工原料
【英文标准名称】:Industrialcommunicationnetworks-Fieldbusspecifications-Part3-18:Data-linklayerservicedefinition-Type18elements
【原文标准名称】:工业通讯网络.数据总线规范.第3-18部分:数据联络层设备定义.18型元件
【标准号】:IEC61158-3-18-2007
【标准状态】:现行
【国别】:国际
【发布日期】:2007-12
【实施或试行日期】:
【发布单位】:国际电工委员会(IX-IEC)
【起草单位】:IEC/SC65C
【标准类型】:()
【标准水平】:()
【中文主题词】:总线系统;总线;电路网络;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;数据设备;数据传送;定义;数字的;数字数据;数字工程;电子数据处理;电气工程;电子仪器;电子系统;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;接口;链路层;开放系统互连;OSI;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;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】:N18;P76
【国际标准分类号】:25_040_40;35_100_20;35_160
【页数】:28P;A4
【正文语种】:英语