How to Read Siemens PLC Part Numbers

Siemens PLC and industrial automation part numbers are exact equipment identifiers, not approximate model names. This guide explains how to compare numbers such as 6ES7, 6GK, 6DD, and 6SN references when sourcing a replacement module.

Why every character matters

A Siemens number can identify the product family, hardware type, electrical configuration, communication interface, memory, firmware generation, or revision. Two modules with nearly identical numbers may fit the same rack but perform different functions or require different software.

Common Siemens number families

  • 6ES7: commonly associated with SIMATIC PLC, I/O, communication, and interface products.
  • 6GK: commonly associated with industrial communication and networking hardware.
  • 6DD: often associated with SIMADYN and related control, processor, communication, or technology modules.
  • 6SN: commonly associated with SIMODRIVE and CNC or servo-drive hardware.

These prefixes help narrow a search, but the full code is still required. Do not treat a shared prefix as evidence of interchangeability.

How to compare an installed label

  1. Photograph the complete product label before removing the module.
  2. Record every character, dash, space, and suffix.
  3. Check for a separate hardware version, firmware version, revision, or option code.
  4. Compare the rack, slot, connector, and terminal arrangement.
  5. Confirm the supported PLC, drive, or CNC family in the system documentation.

Hyphenated and compact formats

Some labels or databases show the same reference with or without hyphens. For example, a listing may include both a market-facing number and a compact article number. Confirm that the sequence of letters and digits is identical before relying on the alternative format.

Can the final suffix be ignored?

No. The ending characters can represent a revision, configuration, interface, voltage, or product generation. A difference at the end of the code should be investigated as carefully as a difference at the beginning.

Where to continue your search

Browse Siemens PLC communication modules, digital I/O modules, distributed I/O, and Siemens CNC drive modules by exact part number.

Independent reseller notice

Outdwella is an independent reseller and is not affiliated with Siemens. Siemens names and part numbers are used only for product identification. Always validate compatibility using the equipment manufacturer’s technical documentation.