Siemens 6ES7 321-1BL00-0AA0 is a SM321 digital input module for SIMATIC S7-300 that provides 32 DC 24 V inputs. The card offers 32 discrete 24 V DC inputs on a single module with a 40-pin interface to the backplane, designed for grouping 32 inputs. Typical applications include wiring sensors and switches for factory automation and process control, with compatibility noted for SIMATIC S7-300 systems and ET 200M backplane configurations.
