6ES7221-1BH32-0XB0 SM 1221 16-Channel Digital Input Module 24V DC | Siemens

The Original New Siemens 6ES7221-1BH32-0XB0 SIMATIC S7-1200 SM 1221 Digital Input Module is a 16-channel digital input signal module designed for scalable I/O expansion in S7-1200 automation systems. It converts external 24V DC digital signals from field devices into internal signal levels for the controller, enabling reliable and flexible signal acquisition. The 16 inputs are organized in four isolated groups of four and support both sink and source wiring configurations, making it suitable for a wide range of industrial automation applications. Fully compatible with all S7-1200 CPUs (except CPU 1211C).

Core Engineering Highlights:
16 digital inputs (24V DC) | Sink/Source configurable (IEC Type 1 sink) | 4 isolated groups of 4 inputs | 0.2–12.8 ms configurable input filter (selectable in groups of 4) | 130 mA backplane bus current | 2.5 W typical power loss | 24V DC rated voltage | 500 m shielded / 300 m unshielded cable length | IP20 protection | –20°C to +60°C operating temperature

Key Features:

• Original New Siemens 6ES7221-1BH32-0XB0 module

• 16 digital inputs (24V DC, sink/source configurable)

• Input characteristic curve per IEC 61131, Type 1

• 4 isolated groups of 4 inputs for enhanced noise immunity

• Configurable input filter: 0.2, 0.4, 0.8, 1.6, 3.2, 6.4, and 12.8 ms, selectable in groups of four

• Supports both sink and source wiring configurations

• Diagnostics indication LED for input status

• 130 mA backplane bus current consumption (5V DC)

• 4 mA per channel input current (from load voltage L+)

• 2.5 W typical power loss

• IP20 protection for control cabinet installation

• 500 m shielded / 300 m unshielded maximum cable length

• Removable terminal block for simplified wiring

• Marine approval included

• Wide operating temperature: –20°C to +60°C

Applications:

• Digital signal acquisition from sensors, pushbuttons, limit switches, and proximity sensors

• Machine automation and control panel I/O expansion

• Conveyor and material handling systems

• Packaging machinery and assembly lines

• Factory automation and process control systems

• High-density input applications requiring isolated groups and configurable filtering

Technical Specifications:

System Compatibility:

• Siemens SIMATIC S7-1200 controllers (all CPUs except CPU 1211C)

• S7-1200 signal modules (SM) for I/O expansion

• TIA Portal engineering framework (STEP 7 Basic / Professional)

• 24V DC control systems

Typical System Architecture:
S7-1200 CPU (e.g., CPU 1214C DC/DC/DC)
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6ES7221-1BH32-0XB0 SM 1221 Digital Input Module (16 channels, 4 isolated groups)
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Additional S7-1200 Signal Modules (SM) / Signal Boards (SB) / Communication Modules (CM)
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Field Devices (Sensors, Pushbuttons, Limit Switches, Proximity Sensors)
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TIA Portal Engineering (STEP 7 Basic / Professional)

Related Products:

• 6ES7221-1BF32-0XB0 – SM 1221 8-channel digital input module (8DI, 24V DC)

• 6ES7222-1BH32-0XB0 – SM 1222 16-channel digital output module (16DO, 24V DC, 0.5A)

• 6ES7223-1BH32-0XB0 – SM 1223 8DI / 8DO combination module

• 6ES7214-1AG40-0XB0 – CPU 1214C DC/DC/DC (14DI/10DO/2AI)

• 6ES7274-1XF30-0XA0 – SIMATIC Memory Card for S7-1200

PLC ERA is an independent industrial automation distributor supplying 100% genuine Original New products through established global supply channels. Siemens, SIMATIC, S7-1200, and TIA Portal are trademarks of Siemens AG.