Siemens AG 221-1BF22-0XA0 Digital Input Module

Siemens 6ES7221-1BF22-0XA0 EM 221 digital input module provides eight 24 V DC digital inputs with galvanic isolation for the SIMATIC S7-200 family (CPU 221/222/224/224 XP/226). It supports both current sourcing and current sinking sensors, enabling straightforward wiring of common field devices such as pushbuttons, limit switches, and proximity sensors. The EM 221 interface translates discrete on/off states into the PLC, while isolation enhances noise immunity and protects the CPU from transients on the I/O lines. With eight input channels in a compact package, this module is well suited for small automation tasks where quick I/O expansion is needed without redesigning the control cabinet. Typical applications include machine controls, packaging lines, conveyors, and automated test rigs that rely on reliable binary sensing. The part number 6ES7221-1BF22-0XA0 identifies an 8-channel 24 V DC digital input module designed specifically for S7-200 CPU families 221/222/224/224 XP/226, and it remains compatible with the Siemens engineering ecosystem and standard field wiring practices for 24 V DC sensing networks.