理解S7-200网络通讯的基本概念-毕业论文外文文献翻译.docxVIP

英文资料原文Understanding the Basics of S7-200 NetworkCommunicationsSelecting the Communication Interface for Your NetworkThe S7-200 is designed to solve your communications and networking needs by supporting not only thesimplest of networks but also supporting more complex networks. The S7-200 also provides tools thatallow you to communicate with other devices, such as printers and weigh scales which use their owncommunications protocols.The S7-200 supports many different types of communication networks. The selection of a network isperformed within the Set PG/PC Interface property dialog. A selected network is referred to as anInterface. The different types of interfaces available to access these communication networks are:1. PPI Multi-Master cables2. CP communication cards3. Ethernet communication cardsTo select the communication interface forSTEP 7--Micro/WIN, you perform the following steps. SeeFigure 7-1.1. Double-click the icon in the Communications Setupwindow.2. Select the interface parameter forFigure 7-1 STEP 7--Micro/WINCommunications InterfacePPI Multi-Master CablesThe S7-200 supports communication through two differenttypes of PPI Multi-Master cables. These cable types permitcommunication through either an RS-232 or a USBinterface.As shown in Figure 7-2, selecting the PPI Multi-Mastercable type is simple. You perform the following steps:1. Click the Properties button on the Set PG/PCInterface property page.2. Click the Local Connection tab on the Propertiespage.3. Select the USB or the desired COM port .Figure 7-2 PPI Multi-Master Cable SelectionTipPlease note that only one USB cable can be used at a time.TipExamples in this manual use the RS-232/PPI Multi-Master cable. The RS-232/PPI Multi-Master cablereplaces the previous PC/PPI cable. A USB/PPI Multi-Master cable is also available. Refer toAppendix E for order numbers.Using Master and Slave Devices on a PROFIBUS NetworkThe S7-200 supports a master-slave network and can function as either a master or aslav