Product Overview

SIMATIC S7-400 Digital Input Module SM 421 - Isolated 32 DI; 24 V DC

This robust digital input module is designed for the SIMATIC S7-400 automation system, featuring 32 optically isolated digital inputs operating at 24 V DC. The SM 421 module provides reliable signal acquisition for industrial automation applications with enhanced electrical isolation for safe operation in demanding environments.

Key Features

• Input Configuration: 32 digital inputs with optical isolation
• Operating Voltage: 24 V DC
• Current Consumption: 20 mA per input
• Power Consumption: 6 W
• Input Type: Sinking inputs
• Isolation: Optically isolated for enhanced safety and noise immunity
• Compatibility: Designed for SIMATIC S7-400 system integration

Technical Specifications

• Article Number: 6ES7421-1BL01-0AA0
• Net Weight: 0.770 kg
• Packaging Dimensions: 23.30 x 29.70 x 4.10 cm
• Country of Origin: Germany
• EAN: 4019169021463
• UPC: 662643186635

Compliance & Certifications

• RoHS Compliance: Compliant since 01.03.2008
• WEEE Directive: Take-back obligation applicable
• Export Control: AL: N / ECCN: N
• Product Lifecycle: PM300 Active Product (phase-out since 01.10.2025)

Environmental & Safety Information

• This product contains substances of very high concern (SVHC) as per REACH Article 33:
• Lead monoxide (lead oxide) - concentration >0.1% w/w
• Tris(4-nonylphenyl, branched and linear) phosphite (TNPP) with ≥0.1% w/w of 4-nonylphenol
• These substances are not expected to pose risks when used as intended, including proper disposal.

Applications

• Digital signal acquisition from sensors and switches
• Process monitoring and control
• Safety-critical applications requiring isolated inputs
• High-density input configurations in compact installations

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Technical Datasheet

Product Information

SM 421 Digital Input Module Family