带有PN口的最低端300系列CPU就行，我们常用的小裁断机用314C-2PN/DP，因为有的行业对于200CPU不认可（涉及到软件不兼容，备件不同用等问题）。价格应该是性能越低价格越低，但不排除有其他商业因素，你可以选几个低端CPU询一下价格。下面是314C的组态属性。

Central modules of type CPU 314C-2 PN/DP：

6ES7 314-6EH04-0AB0

Work memory 192KB; 0.06ms/1000 instructions; DI24/DO16; AI5/AO2 integrated; 4 pulse outputs (2.5kHz); 4 channel counting and measuring with incremental encoders 24V (60kHz); integrated positioning function; MPI+ DP connector (DP master or DP slave); PROFINET IO-Controller; supports RT/IRT; PROFINET interface and 2 ports; MRP; multi-tier configuration up to 31 modules; send and receive capability for direct data exchange; constant bus cycle time; routing; S7 Communication (loadable FBs/FCs); firmware V3.3