Siemens SIMATIC S7-300 SM321 Digital Input Module

Description

The 6ES7321-1BL00-0AA0 is a SM321 digital input module for the Siemens SIMATIC S7-300 PLC system. It provides 32 optically isolated digital inputs for 24V DC signals. This module is a workhorse in industrial automation, known for its reliability and durability in demanding environments. It is an essential component for monitoring sensors, switches, and other digital field devices.

Specifications

• Manufacturer: Siemens
• Product Line: SIMATIC S7-300
• Module Type: SM321 Digital Input Module
• Part Number: 6ES7321-1BL00-0AA0
• Number of Inputs: 32
• Input Voltage: 24V DC
• Isolation: Optically Isolated
• Required Connector: 40-pin

Label Info

• Order No.: 1P 6ES7 321-1BL00-0AA0
• Serial No.: S C_L9403540
• Hardware Version (E-Stand): 01

Application

This module is ideal for expanding the I/O capability of an S7-300 controller in various applications such as manufacturing lines, process control, building automation, and material handling systems.

Country of Origin

Made in Germany.

CO2 Impact

Opting for this pre-owned module instead of a new one prevents the emission of approximately 10 kg of CO2, contributing to a more sustainable industrial sector.

Availability

This module is a legacy component but is available as a tested, used spare part. Order now from PLC2Day for expert support and fast delivery.

FAQ

This module requires a 40-pin front connector, such as the Siemens part number 6ES7392-1AM00-0AA0, for wiring the field signals.

No, this module is specifically designed for the SIMATIC S7-300 PLC series and the ET 200M distributed I/O system. It is not compatible with S7-400 central racks.

The input delay for the 6ES7321-1BL00-0AA0 is configurable in the hardware settings of your STEP 7 project, typically ranging from 0.1ms to 20ms to filter out signal noise.

Last Update: Friday, March 13, 2026

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