理解S7200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 Network Communications Selecting the Communication Interface for Your Network The S7-200 is designed to solve your communications and networking needs by supporting not only the simplest of networks but also supporting more complex networks. The S7-200 also provides tools that allow 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 an Interface. The different types of interfaces available to access these communication networks are: 1. PPI Multi-Master cables 2. CP communication cards 3. Ethernet communication cards To select the communication interface for STEP 7--Micro/WIN, you perform the following steps. See Figure 7-1. 1. Double-click the icon in the Communications Setup window. 2. Select the interface parameter for 1 1 2 2 Figure 7-1 STEP 7--Micro/WINCommunications Interface PPI Multi-Master Cables The S7-200 supports communication through two different types of PPI Multi-Master cables. These cable types permit communication through either an RS-232 or a USB interface. As shown in Figure 7-2, selecting the PPI Multi-Master cable type is simple. You perform the following steps: 1. Click the Properties button on the Set PG/PC Interface property page. 2. Click the Local Connection tab on the Properties page. 3. Select the USB or the desired COM port . 1 1 2 2 3 3 Figure 7-2 PPI Multi-Master Cable Selection Tip Please note that only one USB cable can be used at a time. Tip Examples in this manual use the RS-232/PPI Multi-Master cable. The RS-232/PPI Multi-Master cable replaces the previous PC/PPI cable. A USB/PPI Multi-Master cable is also available. Refer to Appendix E for order numbers. Using Master and Slave Devices on a PROFIBUS Network The S7-200 supports a master