现在用的是2块315-2DP的PLC，一个做主站，一个做从站，给主站的PROFIBUS地址为1，从站的PROFIBUS地址为4，程序通过PC Adapter电缆下载的，下载的MPI地址为默认的2。现在出现如下问题:
1.在PROFIBUS的NetPro编译时出现如下警告错误:
Outputs for station'SIMATIC 300 MASTER':
Warning: Attention: in station SIMATIC 300 SLAVE there are additional nodes that also have to be reloaded.
Outputs for station'SIMATIC 300 SLAVE':
Warning: Attention: in station SIMATIC 300 MASTER there are additional nodes that also have to be reloaded.
Result: 0 error(s), 2 warning(s)
我一开始认为警告错误没什么影响，但是一运行cpu初始化好后SF灯就亮，BF灯不亮，这到底是为什么呢？希望能够得到大虾们指导