The FM 353 is a positioning module for controlling stepper motors. It can perform many functions for solving a wide variety of positioning tasks, and offers a high level of precision, dynamic response, and user-friendliness.
In contrast to modules which control servomotors, the FM 353 requires no position decoding system

It can be used in all low-load positioning tasks and where there are no major load fluctuations. When these prerequisites are fulfilled, virtually the same degree of accuracy can be achieved with the FM 353 and stepper motors (µm-range) as with servomotors.  

The FM 353 is used in the SIMATIC S7-300, C7 and ET 200M on S7 masters. Operation with WinAC Slot 41x is possible.