Siemens SIMATIC S7-300 digital input module SM321, model 6ES7 321-1BL00-0AA0, provides 32 discrete 24V DC input points for the S7-300 family. The 6ES7 321-1BL00-0AA0 is a DI module that accepts external 24V signals from sensors and switches and translates them to the PLC logic. With 32 inputs, it supports modular I/O expansion in Siemens automation cabinets and packaging lines, designed for use with SIMATIC S7-300 controllers as part of the SM321 family. Typical applications include reading signals from pushbuttons, limit switches, and proximity sensors in factory automation.
