OVERVIEW

Official designation: SIEMENS 6ES7321-1BL00-0AA0 (SIMATIC SM 321, Digital Input Module)

Role/Application: Digital Input Module SM 321 for the SIMATIC S7-300 PLC, providing 32 isolated 24 V DC inputs for reliable signal acquisition from switches and 2 to 4-wire proximity sensors in industrial automation.

KEY SPECS SUMMARY

Power: 24 V DC (20.4 to 28.8 V)

Interfaces / Ports: 1 x 40-pin front connector

Indicators: Green LED for each channel

Operating Temp: Minus 25 to 70 degrees C

Platform / Compatibility: SIMATIC S7-300, ET 200M

Limit: 32 inputs, 1.2 ms to 4.8 ms delay

Lifecycle: Phase Out Announce

FREQUENTLY ASKED QUESTIONS

Technical Specifications:

Q: What is the input voltage range that corresponds to a logical one signal?

A: The logical one signal voltage range is from 13 V to 30 V DC, complying with IEC 61131, type 1.

Wiring & Installation:

Q: What are the maximum recommended cable lengths for both shielded and unshielded inputs?

A: Maximum cable length is 1000 m for shielded wire and 600 m for unshielded wire.

Troubleshooting & Compatibility:

Q: What is the channel grouping for potential separation and is there diagnostic capability?

A: Inputs are isolated in groups of 16, and the module has no built-in diagnostic functions.

Replacement & Upgrades:

Q: What is the current manufacturer status regarding the product's availability and future?

A: The module is currently in the Phase Out Announce status, indicating future product cancellation.