Siemens 6ES7401-1DA01-0AA0 Digital Input Module

Siemens 6ES7401-1DA01-0AA0 is a SIMATIC S7-400 CR3 central rack that provides a four-slot backplane for mounting S7-400 modules in a single, centralized chassis. In standard automation architectures, this CR3 rack serves as the backbone for assembling a compact control cabinet where CPU, I/O, and support modules plug into the central backplane, enabling reliable interconnectivity and straightforward expansion up to four slots. The rack is engineered from sheet steel to withstand industrial environments and to offer rigid mechanical support for plug-in modules, with a footprint compatible with Siemens' CR3 central rail system. Used in conjunction with compatible S7-400 backplanes and module carriers, the 6ES7401-1DA01-0AA0 enables scalable configuration, allowing you to start with a four-slot core and add modules as the control requirements grow. This part number is listed in Siemens catalogs as a central CR3 rack with four slots, and you may encounter it in supplier listings as a core component for S7-400 installations requiring a CR3 central rack.