Siemens S7-300 SM321 Ex digital input module / 6ES7321-7RD00-0AB0

Siemens S7-300 SM321 Ex digital input module; exact model specifications from ST70 2021. Confirm host configuration, revision, accessories and current availability before ordering.

Manufacturer part number: 6ES7321-7RD00-0AB0
Brand: Siemens
Category: PLC and HMI
Catalog status: Request a quotation

Technical specifications

Controller family: SIMATIC S7-300
Digital inputs: 4; isolated; NAMUR
Application scope: Signals from intrinsically safe digital field equipment; verify complete Ex installation requirements
Document pages: ST70 2021 PDF610 / printed5/122
Current lifecycle status: Not established by historical2021 catalogue; confirm current lifecycle and supply separately

Manufacturer technical catalog · Siemens ST70 2021; exact ordering/technical row PDF610 · en · PDF · ST70 2021Manufacturer source: Siemens · Model explicitly covered in family document · Covered models: 6ES7321-7RD00-0AB0 · Checked: 2026-10-22Official 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.