Glossary Updates12 new terms added to the glossaries · October 2, 2026, 22:44 CEST
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Glossary · Automation fundamentals, platforms and components

LOGO! (Siemens logic module)

Also known as: Siemens LOGO!, LOGO! logic module

German: LOGO!

In industrial automation, LOGO! is a compact logic module product line from Siemens for small control tasks, programmed with graphical function blocks or ladder logic in the vendor's software or, for simple programs, directly on the device.

  • Automation components
  • Vendor product

In one sentence

LOGO! is a Siemens logic module line for small control tasks such as lighting, doors or small machines, programmed graphically.

Example

A LOGO! module controls the ventilation and lighting of a greenhouse based on time switches and a temperature input.

How it applies

  • Engineering: Logic modules suit small tasks with limited I/O, such as lighting, gates, pumps or simple machines, where a full PLC would be oversized.
  • Maintenance: Programs should be backed up and version-controlled like any control software, even on small devices.
  • Documentation: Provide the program printout or file, the I/O assignment and the parameter values with the machine documentation. If the logic module handles safety-relevant functions, check that the device is rated for them; standard logic modules are not safety controllers.

Logic module vs. PLC

Logic modules are simpler and cheaper than PLCs, with fewer I/O and programming features. Other vendors offer similar product lines.

Keep in mind: Product names, versions and features of LOGO! change over time. Check the current Siemens documentation before relying on specific capabilities.

By knowledge.aitechdoc.world · Published September 26, 2026 · Last reviewed

Source: AI TechDoc Blog editorial definition, based on Siemens product documentation

Definitions follow the cited standards and specifications. Where a source is a copyrighted publication, such as an ISO, IEC or EN standard, the definition is a close paraphrase, not a verbatim quotation, so as not to infringe copyright. We recommend reading the original publication. The sections “How it applies” are editorial commentary by AI TechDoc Blog and are not part of any standard.

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