SIMATIC S7-400 SM421 32-input digital module / 6ES7421-1BL01-0AA0

SIMATIC S7-400 SM421 32-input digital module; specifications are qualified to the May 2017 official catalogue. Verify current lifecycle, supplied revision and project configuration when requesting a quote.

Manufacturer part number: 6ES7421-1BL01-0AA0
Brand: Siemens
Category: PLC and HMI
Catalog status: Request a quotation

Technical specifications

Controller family: SIMATIC S7-400
Module designation: SM421
Width (mm): 25
Height (mm): 290
Depth (mm): 210
Approximate weight (g): 500
Digital inputs: 32
Rated input: 24 V DC
Input signal 0: -30..5 V DC
Input signal 1: 13..30 V DC
Typical input current (mA): 7
Channels per isolation group: 32
Isolation from backplane: Yes
Document pages: PDF 54, 55, 56
Reviewed document edition: ST 400 / May 2017 / E86060-K4678-A151-A1-7600

Manufacturer technical catalog · ST 400 / May 2017 / E86060-K4678-A151-A1-7600 · en · PDF · ST 400 / May 2017 / E86060-K4678-A151-A1-7600Manufacturer source: Siemens · Model explicitly covered in family document · Covered models: 6ES7421-1BL01-0AA0 · Checked: 2026-10-17Official manufacturer source

This sheet provides a quick technical summary. For design, installation and final selection, review the latest official manufacturer documentation and verify the complete part number.