【正文】 00.2. Select the baud rate for the S7200.3. Download the system block to the S7200.12Figure 74 Configuring the S7200 CPUTipSelection of all baud rate options is permitted. STEP 7Micro/WIN validates this selection during the download of the System Block. Baud rate selections that would prevent STEP 7Micro/WIN from municating with the S7200 are prevented from being downloaded.Setting the Remote AddressBefore you can download the updated settings to the S7200, you must set both the munications (COM) port of STEP 7Micro/WIN (local) and the address of the S7200 (remote) to match the current setting of the remote S7200. See Figure 75.After you download the updated settings, you may need to reconfigure the PG/PC Interface baud rate setting (if different from the setting used when downloading to the remote S7200). Refer to Figure 73 to configure the baud rate.Figure 75 Configuring STEP 7Micro/WINSearching for the S7200 CPUs on a NetworkYou can search for and identify the S7200 CPUs that are attached to your network. You can also search the network at a specific baud rate or at all baud rates when looking for S7200s.Only PPI MultiMaster cables permit searching of all baud rates. This feature is not available if municating through a CP card. The search starts at the baud rate that is currently selected.1. Open the Communications dialog box and doubleclick the Refresh icon to start the search.2. To search all baud rates, select the Search All Baud Rates check box. 2.Selecting the Communications Protocol for Your NetworkThe following information is an overview of the protocols supported by the S7200 CPUs.1. PointtoPoint Interface (PPI)2. MultiPoint Interface (MPI)3. PROFIBUSFigure 76 Searching for CPUs on a NetworkBased on the Open System Interconnection (OSI) sevenlayer model of munications architecture, these protocols are implemented on a token ring network which conforms to the PROFIBUS standard as defined in the European Standard EN 50170. These protocols are asynchronous, characterbased protocols with one start bit, eight data bits, even parity, and one stop bit. Communications frames depend upon special start and stop characters, source and destination station addresses, frame length, and a checksum for data integrity. The protocols can run on a network simultaneously without interfering with each other, as long as the baud rate is the same for each protocol.Ethernet is also available for the S7200 CPU with expansion modules CP2431 and CP2431 IT.PPI ProtocolPPI is a masterslave protocol: the master devices send requests to the slave devices, and the slave devices respond. See Figure 77. Slave devices do not initiate messages, but wait until a master sends them a request or polls them for a response.Masters municate to slaves by means of a shared connection which is managed by the PPI protocol. PPI does not limit the number of masters that can municate with any one slave。 however, you cannot install more than 32 masters on the network.Figure 77 PPI NetworkS7200 CPUs can act as master devices while they are in RUN mode, if you enable PPI master mode in the user program. (See the description of SMB30 in Appendix D.) After enabling PPI master mode, you can use the Network Read or the Network Write instructions to read from or write to other S7200s.While the S7200 is acting as a PPI master, it still responds as a slave to requests from other masters.PPI Advanced allows network devices to establish a logical connection between the devices. With PPI Advanced, there are a limited number of connections supplied by each device. See Table 73 for the number of connections supported by the S7200.All S7200 CPUs support both PPI and PPI Advanced protocols, while PPI Advanced is the only PPI protocol supported by the EM 277 module.Table 73 Number of Connections for the S7200 CPU and EM 277 ModulesModuleBaud RateConnectionsS7200 CPU Port 0 Port 1 kbaud, kbaud, or kbaud4 kbaud, kbaud, or kbaud4EM 277 Module kbaud to 12 Mbaud6 per moduleMPI ProtocolMPI allows both mastermaster and masterslave munications. See Figure 78. To municate with an S7200 CPU, STEP 7Micro/WIN establishes a masterslave connection. MPI protocol does not municate with an S7200 CPU operating as a master.Network devices municate by means of separate connections (managed by the MPI protocol) between any two devices. Communication between devices is limited to the number of connections supported by the S7200 CPU or EM 277 modules. See Table 73 for the number of connections supported by the S7200. For MPI protocol, the S7300 and S7400 PLCs use the XGET and XPUT instructions to read and write data to the S7200 CPU. For information about these instructions, refer to your S7300 or S7400 programming manual.Figure 78 MPI NetworkPROFIBUS ProtocolThe PROFIBUS protocol is designed for highspeed munications with distributed I/O devices (remote I/O). There are many PROFIBUS devices available from a variety of manufacturers. These devices range from simple input or output modules to motor controllers and PLCs.PROFIBUS networks typically have one master and several slave I/O devices. See Figure 79. The master device is configured to know what types of I/O slaves are connected and at what addresses. The master initializes the network and verifies that the slave devices on the network match the configuration. The master continuously writes output data to the slaves and reads input data from them.Figure 79 PROFIBUS NetworkWhen a DP master configures a slave device successfully, it then owns that slave device. If there is a second master device on the network, it has very limited access to the slaves owned by the first master.TCP/IP Protocol