S7-300 ‘s modular structure, can be different according to the application object, use of different models and different number of modules, and modules can be installed in the same rack (rail) or on more than one rack. Matching with the CPU3121FM and CPU313 modules can only be installed in a rack. In addition to the power supply module, CPU module and interface modules, one rack only and then install 8 signal module or modules.
CPU314/315/315-2DP expandable up 4 rack, IM360/IM361 interface module S7-300 backplane bus connection from one machine to the next frame.
Central processing unit, always in the No. 0 2nd trough, 1th, installing power supply module, 3rd tank always install interface modules. 4~11, slots, are free to distribute the signal module, modules and communication modules. Need to be aware of is that slot number is relative, each physical slot rack rails do not exist.
Used to send IM360 interface module, installed in the rack, No. 0, 3rd slot. Via a dedicated cable, data sent from the IM360 to a IM361 interface modules with receive functions. Can also use more economic IM365 module.