第三章现场控制站的结构和设备本章介绍现场控制站的硬件结构。将现场来的信号转换成使CPU能读取的数字信号的单元称为输入/输出模件(I/0模件)。I/0模件信号借助节点接口单元(NIU)送至现场控制单元(FCS),现场控制单元中有一个CPU来进行生产过程控制。本章将确认每种功能,并理解其结构。目录3.1关键词条.......................................................................................................................................13.2硬件...............................................................................................................................................23.2.1安装方式..................................................................................................................................23.2.2硬件组态..................................................................................................................................43.3信号流图.......................................................................................................................................63.4现场控制单元(FCU).................................................................................................................73.5节点接口单元(NIU).................................................................................................................83.6I/O模件.........................................................................................................................................93.7冗余度和可靠性.........................................................................................................................113.7.1FCS的冗余度和可靠性.........................................................................................................113.7.2FCS处理器卡的双重化冗余及其高可靠性........................................................................123.8FCS的结构...................................................................................................................................133.1关键词条下列各条为本章中将研究的内容.(1)现场控制单元·························3.2(2)节点·····························3.2(3)FCU的信号流图·························3.4(4)输入/输出模件·························3.6(5)冗余度和可靠性························3.73.2硬件有8种形式的硬件可供选择,可从下列各项中选出最佳组合:功能:标准的或扩展的组态:单机或双重化冗余安装体:机柜或19″机架3.2.1安装方式1台FCU和多个节点安装在专用的机柜内,也可安装在通用的19″机架上。它们可自由地分开或组合,安装在机柜和机架上。例如:FCU和一些节点安装在机柜内,同时另一些节点安装在地仪表盘上的机架中。(1)机柜形FCS机柜形FCS正面:1台FCU和3个节点(1个节点最多可容纳4个I/O模件插槽)。背面:3个节点(1个节点最多可容纳5个I/O模件插槽)。用于安装节点机柜正面和背面总共可安装6个节点(每个节点中最多可安装5个I/O模件插槽)。(2)19″架装FCS组成:FCU安装用机架。节点安装用机架,每个机架中可安装2个插槽。I/O扩展形机架,每个可安装3个模件插槽。结构:19″机架。安装:仪表盘上;通用机柜中;本地表盘上。现场控制单元(FCS)在机架上的安装。图3.2FCS在机架上的安装3.2.2硬件组态FCS由一个现场控制单元(FCU),最多可由8个节点组成,由远程输入/输出总线(RIO总线)连接起来,如图3.3所示。现场控制单元(FCU)FCU为一个微处理器组件,完成FCS的控制和计算。节点(远程I/O单元)节点为一种信号处理...