Siemens 6ES7221-1BH22-0XA0 is a SIMATIC S7-200 digital input expansion module (EM221) that adds 16 digital inputs (DI) at 24 V DC to a SIMATIC S7-200 system. It is compatible only with S7-22x CPUs and supports both sinking and sourcing input configurations for flexible wiring. As a spare-part EM221 module, it plugs into the S7-200 backplane to expand the controller’s input count for field devices such as pushbuttons, switches, and proximity sensors in small automation tasks.
