Spare-part fit for S7-200 racks
The Siemens 6ES7221-1BF22-0XA0 is a spare-part EM 221 digital input module for the SIMATIC S7-200 family, specifically the 22X CPU series. It provides 8 digital inputs rated for 24 V DC, with both sinking and sourcing wiring supported.
Signal thresholds and wiring reach
The module reads a logic '1' signal between +15 and +30 V DC, with a typical input current of 4 mA at the '1' level. Logic '0' is 0 to 5 V DC. Maximum permissible quiescent current from a 2-wire sensor is 1 mA. Unshielded sensor cable runs up to 300 m; shielded runs up to 500 m. Inputs are grouped in blocks of 4 with optocoupler isolation between groups.
Panel footprint and power draw
The module measures 46 mm wide, 80 mm high, and 62 mm deep, with plug-in I/O terminals for quick replacement. Typical power loss is 2 W; it draws 30 mA from the 5 V DC backplane bus.
Sourcing for an active spare
The 6ES7221-1BF22-0XA0 carries a current lifecycle stage — it is an active spare part for installed S7-200 systems.