Siemens PLC has 4 categories, dozens of model types, PLC different communication protocols supported by the different are not the same. s7-200 series support protocols: PPI, MPI, PROFIBUS, Ethernet, S7 protocol, AS-INTERFACE, USS, MODBUS, free port. s7-300 \ 400 series support protocols There are: MPI, PROFIBUS, ETHERNET network, ISO protocol, ISO-ON-TCP, MODBUS and so on. The same point is the same protocol physical transmission medium is the same. For example, the S7 protocol can use DP and Ethernet as the transmission medium. The difference is that each protocol corresponds to a different configuration mode and program.
The S7 communication is used between 1500 and 1200, and the general steps are as follows: 1. First, add a 1500 device, and then add a 1200 device, select S7 connection, the process needs to pay attention to the password can't be set to allow PUT/GET access. 2. In the program, add the S7 communication commands, the GET command is to receive the partner's data, and PUT For sending data to the partner, for example, 1500 to receive 1200 data, use the GET instruction, and vice versa to send data to 1200 use the PUT instruction.