Siemens 6ES5355-3UA11 is a SIMATIC S5 memory submodule (355) that provides RAM/EPROM storage for the S5-135U and S5-155U central units. It includes three slots for memory submodules 373/377 and is sold as an exchange-only memory module. Typically used with CPU 9461947 within the S5-155U family, the 6ES5355-3UA11 extends the 355 memory subsystem in legacy Siemens automation setups.
