Product Overview

SIMATIC S7-300 Digital Input SM 321, Isolated, 16 DI, 24 V DC, 1x 20-pole

This high-performance digital input module provides sixteen isolated digital inputs with reliable 24V DC signal acquisition capability. Each input channel features galvanic isolation for enhanced safety and noise immunity, making it ideal for connecting switches, proximity switches, sensors, and other digital devices in demanding industrial automation applications with SIMATIC S7-300 systems.

Key Features

• Input Channels: 16 optically isolated digital inputs
• Operating Voltage: 24 V DC (rated input voltage)
• Input Current: 10 mA typical per channel
• Isolation: Galvanic isolation between channels and backplane bus
• Connection: 1x 20-pole connector for secure signal connections
• Status Indication: Green LED status display for each channel
• Sensor Compatibility: Supports 2-wire, 3-wire, and 4-wire proximity switches

Technical Specifications

• Article Number: 6ES7321-1BH02-0AA0
• Number of Digital Inputs: 16 channels
• Input Voltage: 24 V DC
• Input Current: 10 mA per channel
• Connection Type: 20-pole connector
• Isolation: Optocoupler isolation between channels and system
• Dimensions (W x H x D): 40 x 125 x 120 mm
• Net Weight: 0.237 kg
• Packaging Dimensions: 12.80 x 15.20 x 5.00 cm
• Power Loss: 3.5 W typical
• Country of Origin: Germany
• EAN: 4025515051893
• UPC: 040892561715

Input Characteristics

• Signal Type: Sinking inputs compatible with standard 24V DC sensors
• Input Impedance: High impedance for reliable signal detection
• Switching Threshold: Compliant with IEC 61131-1 standards
• Input Filtering: Built-in noise filtering for stable operation
• Response Time: Fast response for real-time applications
• Wire Compatibility: Standard industrial wiring practices

Compliance & Certifications

• RoHS Compliance: Compliant since 31.03.2008
• WEEE Directive: Take-back obligation applicable
• Export Control: AL: N / ECCN: 9N9999
• Product Lifecycle: PM400 - Announcement of product phase-out (since 01.10.2023)
• Product Class: Standard product with return capability within guidelines

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
• These substances are not expected to pose risks when used as intended, including proper disposal.

Applications & Sensor Compatibility

• Digital Signal Acquisition: Switches, push buttons, and selector switches
• Proximity Sensors: 2-wire, 3-wire, and 4-wire proximity switches
• Safety Systems: Emergency stop switches and safety door contacts
• Process Monitoring: Level switches, pressure switches, and flow sensors
• Machine Control: Limit switches, position sensors, and feedback devices
• Status Monitoring: Indicator lights, alarm contacts, and system status signals

Installation & Configuration

• System Integration: Seamless integration with SIMATIC S7-300 systems
• Configuration: Software-configurable input parameters through STEP 7
• Wiring: Requires 20-pole front connector (ordered separately)
• Installation: Standard S7-300 module mounting in control cabinet
• Diagnostics: Individual channel status monitoring and system diagnostics
• Maintenance: Easy module replacement with comprehensive diagnostic capabilities

Isolation Benefits

• Galvanic Isolation: Electrical isolation between input channels and system
• Noise Immunity: Enhanced protection against electromagnetic interference
• Safety Protection: Isolation voltage protects system from external faults
• Signal Integrity: Maintains clean digital signals in noisy industrial environments
• System Reliability: Prevents ground loops and cross-talk between channels

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Technical Datasheet

Product Information

SM 321 Digital Input Modules Family