HESG324442R13 C脉冲输入卡件
监测以太网接口状态位。8.2.4冗余系统中的SRTP信道命令当配置为冗余IP操作时（参见第1节：更多信息），只有活动单元建立并维护用于信道命令的SRTP客户端连接。备份单元不执行任何SRTP客户端操作。如果尝试SRTP客户端操作，则COMMREQ错误状态返回到本地逻辑程序。当以太网接口从活动状态变为备份状态时，它将关闭所有SRTP客户端连接及其底层TCP连接。由于断开TCP连接可能需要一些时间，因此冗余系统应使用冗余IP地址为每个连接保留一个备用SRTP客户端连接。这将防止在与新活动单元建立新的SRTP客户端连接时出现临时资源问题，而与旧活动单元的先前连接正在关闭。PAC系统™ RX3i和RSTi EP TCP/IP以太网通信用户手册第8节GFK-2224Y 2019年8月编程SRTP信道命令146 8.2.5执行信道命令下图显示了通信请求如何执行信道命令，在这种情况下，建立读取信道。客户端PLC CPU背板以太网接口服务器LAN以太网接口电源流向梯形图程序命令块中的COMMREQ，发送至接口验证命令块，并设置服务器PLC读取请求数据数据读取请求数据客户端CPU的通道。如果命令块无效。如果语法正确，则COMMREQ状态字在第一个重要事件后返回：未能正确及时地建立信道或首次成功传输数据时。3.通道成功设置到服务器PLC后，以太网接口执行命令块中指定的周期性读取。对于PACSystems CPU嵌入式以太网接口，输入CPU模块的机架/插槽位置。适配器名称（模块位置）可由下表中的十六进制字值指示：机架插槽十六进制字数值BLOCK MOVE或DATA_INIT_COMM）。命令块具有以下结构：字偏移描述字1数据块长度（字）字2 WAIT/NOWAIT标志字3 COMMREQ状态字存储器类型字4 COMMREQ状况字地址偏移字5保留字6保留字7及以上数据块（信道命令详细信息）存储器位置1-7（字1）数据块长度的进一步考虑：这是命令块的数据块部分。数据块部分从命令块的字7开始。长度从字7的数据块开始测量，而不是从命令块开始测量。每个命令的正确值以及每个命令的相关长度将在下一节中指定。
Monitoring the Ethernet Interface Status Bits. 8.2.4 SRTP Channel Commands in a Redundant System When configured for Redundant IP operation (see Section 1: for more information), only the active unit establishes and maintains the SRTP Client connections used for the Channel commands. The backup unit does not perform any SRTP Client operations. If SRTP Client operation is attempted, a COMMREQ error status is returned to the local logic program. When the Ethernet interface changes from active to backup state, it takes down all SRTP Client connections and their underlying TCP connections. Because it can take some time to take down a TCP connection, the Redundant system should reserve a spare SRTP Client connection for each connection using the Redundant IP address. That will prevent temporary resource problems when establishing new SRTP Client connections to the new active unit while the previous connections to the old active unit are being taken down. PACSystems™ RX3i and RSTi-EP TCP/IP Ethernet Communications User Manual Section 8 GFK-2224Y August 2019 Programming SRTP Channel Commands 146 8.2.5 Executing a Channel Command The figure below shows how a Communications Request carries out a Channel command, in this case, Establish Read Channel. Client PLC CPU Backplane Ethernet Interface Server LAN Ethernet Interface Power flows to COMMREQ in ladder program Command Block sent to Interface Verify Command Block and set up channel to server PLC Read Request Data Data Read Request Data Data Client CPU . . . . . . Read Request Data Data Data Pulse Data Transfer bit Data Transfer Pulse Data Transfer bit Pulse Data Transfer bit Data Domain of a channel Domain of a TCP connection pulse received Data Transfer pulse received Data Transfer pulse received Domain of a remote server Server Backplane CPU Read Request Data Read Request Data Read Request Data PLC status word is returned immediately if the Command Block is invalid. If the syntax is correct, the COMMREQ status word is returned after the first significant event: upon failure to establish a channel correctly and in a timely manner or upon the first successful transfer of data. 3. After the channel is successfully set up to the server PLC, the Ethernet interface performs the periodic reads as specified in the Command Block. For the PACSystems CPU embedded Ethernet interface, enter the rack/slot location of the CPU module. The adapter name (module position) can be pointed by the hex word value in the table below: Rack Slot Hex Word Value BLOCK MOVE or DATA_INIT_COMM). The Command Block has the following structure: Word Offset Description Word 1 Data Block Length (words) Word 2 WAIT/NOWAIT Flag Word 3 COMMREQ status word Memory Type Word 4 COMMREQ status word Address Offset Word 5 Reserved Word 6 Reserved Words 7 and up Data Block (Channel Command Details) Further Considerations for Memory Locations 1-7 (Word 1) Data Block Length: This is the length in words of the Data Block portion of the Command Block. The Data Block portion starts at Word 7 of the Command Block. The length is measured from the beginning of the Data Block at Word 7, not from the beginning of the Command Block. The correct value for each command, and the associated length of each command, is specified in the next section.
