Siemens 6ES7221-1BF00-0XA0 Digital Input Module

Compact Digital Input Expansion for S7-200 Systems

The Siemens 6ES7221-1BF00-0XA0 serves as an EM 221 digital input expansion module for the SIMATIC S7-200 PLC series . This module adds 8 digital input points to the controller, expanding the system’s capabilities for handling field signals . It accepts 24 V DC signals from sensors, switches, and other field devices. The module’s optically isolated design ensures reliable signal acquisition in industrial environments . Furthermore, this module supports both sinking and sourcing wiring configurations, offering flexibility for various field device connections . Its compact form factor enables efficient use of cabinet space.

Technical Specifications

Specification	Value
Model	6ES7221-1BF00-0XA0
Product Type	EM 221 Digital Input Module
Number of Inputs	8
Input Voltage	24 V DC (rated)
Signal “0” Voltage	0 to 5 V DC
Signal “1” Voltage	15 to 30 V DC
Input Current (Signal “1”)	4 mA typical
Input Delay (0 to 1)	4.5 ms maximum
Backplane Current	30 mA from 5 V DC
Power Loss	2 W typical
Isolation	Optocoupler, groups of 4
Cable Length (Shielded)	500 m maximum
Cable Length (Unshielded)	300 m maximum
Dimensions (W x H x D)	46 mm x 80 mm x 62 mm
Weight	Approx. 150 g

Installation and Connectivity

The Siemens 6ES7221-1BF00-0XA0 mounts directly onto the S7-200 expansion bus, enabling plug-and-play integration. It connects via plug-in I/O terminals, simplifying field wiring and maintenance . The module also supports 2-wire sensors with a permissible quiescent current of up to 1 mA . Its input characteristics comply with IEC 61131, type 1 standards, ensuring compatibility with a wide range of industrial sensors . The module holds various certifications including CE, UL, and ATEX for use in hazardous locations . It also carries maritime approvals such as BV, GL, LR, and CCS .