Siemens 6ES7478-2BA00-0AC0 is the MSM478 Mass Storage Module for the SIMATIC M7-400 automation system. It provides dedicated mass storage with a hard disk drive capacity greater than 500 MB and a 3.5-inch floppy disk drive (1.44 MB). This expansion module attaches to the M7-400 controller to store program data and files alongside the main CPU within the SIMATIC M7-400 family. The part number 6ES7478-2BA00-0AC0 identifies this MSM478 expansion module for use with M7-400 systems.
