运行原理
目前有多种用于提供实时能力的以太网方案: 例如,通过较的协议层禁止 csma/cd 存取过程,并使用时间分片或轮询技术来取代它。其它方案使用交换机,并采用的时间控制方式分配以太网报文。尽管这些解决方案能够比较快和准确地将数据包传送到所连接的以太网节点,但带宽的利用率却很低,特别是对于典型的自动化设备,因为即使是对于非常小的数据量,也必须要发送一个完整的以太网帧。而且,重新定向到输出或驱动控制器以及读取输入数据所需的时间主要取决于执行方式。通常也需要使用一条子总线,特别是在模块化 i/o 系统中,这些系统与 beckhoff k-bus 一样,通过同步子总线系统加快传输速度,尽管如此,这样的同步还是无法避免通讯总线传输的延迟。
通过采用 ethercat 技术,beckhoff 突破了其它以太网解决方案的这些系统限制: 不必再像从前那样在每个连接点接收以太网数据包,然后进行解码并复制过程数据。当帧通过每一个设备(直达 i/o 端子模块)时,ethercat 从站控制器读取与该设备相关的数据。同样,输入数据可以飞速插入至数据流中。帧被传递(仅被延迟几位)过去的时候,从站会识别出相关命令,并进行相应处理。此过程是在从站控制器中通过硬件实现的,因此与协议堆栈软件的 run-time 系统或处理器性能无关。网段中的zui后一个 ethercat 从站将经过充分处理的报文发回,这样该报文就作为一种响应报文由*个从站返回到主站。
从以太网的角度看,ether¬cat 总线网段是一个可接收和发送以太网帧的大型以太网设备。但是,该“设备“不包含带下游微处理器的单个以太网控制器,而只包含大量的 ethercat 从站。与其它任何以太网设备一样,ethercat 不需要通过交换机就可以建立通讯,因而产生一个纯粹的 ethercat 系统。
ie1000 fieldbus box extension box, 8 digital inputs 24 v dc, filter 3.0 ms, 8 mm; i/o connection with connector: 8 mm, 3-pin, snap-on
ie1001 fieldbus box extension box, 8 digital inputs 24 v dc, filter 3.0 ms, m8; i/o connection with connector: m8, 3-pin, screw-type
ie1002 fieldbus box extension box, 8 digital inputs 24 v dc, filter 3.0 ms, m12; i/o connection with connector: m12, 5-pin, screw-type
ie1010 fieldbus box extension box, 8 digital inputs 24 v dc, filter 0.2 ms, 8 mm; i/o connection with connector: 8 mm, 3-pin, snap-on
ie1011 fieldbus box extension box, 8 digital inputs 24 v dc, filter 0.2 ms, m8; i/o connection with connector: m8, 3-pin, screw-type
ie1012 fieldbus box extension box, 8 digital inputs 24 v dc, filter 0.2 ms, m12; i/o connection with connector: m12, 5-pin, screw-type
ie1502 fieldbus box extension box, up/down counter 24 v dc, 100 khz, m12; i/o connection with connector: m12, 5-pin, screw-type
ie2000 fieldbus box extension box, 8 digital outputs 24 v dc, imax = 0.5 a, 8 mm; i/o connection with connector: 8 mm, 3-pin, snap-on
ie2001 fieldbus box extension box, 8 digital outputs 24 v dc, imax = 0.5 a, m8; i/o connection with connector: m8, 3-pin, screw-type
ie2002 fieldbus box extension box, 8 digital outputs 24 v dc, imax = 0.5 a, m12; i/o connection with connector: m12, 5-pin, screw-type
ie2020 fieldbus box extension box, 8 digital outputs 24 v dc, imax = 2 a (∑ 4 a), 8 mm; i/o connection with connector: 8 mm, 3-pin, snap-on
ie2021 fieldbus box extension box, 8 digital outputs 24 v dc, imax = 2 a (∑ 4 a), m8; i/o connection with connector: m8, 3-pin, screw-type
ie2022 fieldbus box extension box, 8 digital outputs 24 v dc, imax = 2 a (∑ 4 a), m12; i/o connection with connector: m12, 5-pin, screw-type
ie2040 fieldbus box extension box, 8 digital outputs 24 v dc, imax = 2 a (∑ 12 a), 8 mm; i/o connection with connector: 8 mm, 3-pin, snap-on
ie2041 fieldbus box extension box, 8 digital outputs 24 v dc, imax = 2 a (∑ 12 a), m8; i/o connection with connector: m8, 3-pin, screw-type
