What it does
CODESYS Development System V3 is an engineering IDE for controller applications. Its editors cover IEC 61131-3 languages and graphical forms such as function block and ladder diagrams, while project configuration, compilers, libraries, debugging, and device setup sit in the same environment. It is intended for PLC and industrial automation development rather than general-purpose application editing. The core Development System is listed at no charge; controller runtimes and optional engineering add-ons are separate products.
Start with a controller project
The Development System's help describes a project as more than a source file: it can include program organization units, task and device configuration, libraries, visualizations, and related files. A first step is to create or select a project template, then configure the target and write controller logic in a suitable IEC 61131-3 editor. The editor set includes text-oriented Structured Text and graphical Function Block Diagram, Ladder Diagram, and Sequential Function Chart forms.
The project view helps keep device-specific objects separate from project-wide POUs. From there, the documented workflow includes compiling, comparing projects, managing libraries, and using online debugging or commissioning features when connected to a compatible controller. These are capabilities described by the documentation, not actions performed here.
Free engineering tool, target-specific costs
The CODESYS Store lists the Development System itself as a free download. The wider product family also includes runtime, fieldbus, visualization, and other packages, some sold under separate license models. That distinction matters: a free IDE does not establish that every controller can run a built application without a target runtime or device-specific license. Verify the controller vendor's supported package and terms before adopting a project for production.
Strengths
- A single IDE provides IEC 61131-3 editors, project configuration, libraries, compilation, and debugging for controller applications.
- Project comparison and reusable libraries support teams maintaining controller code across related applications.
- The core Development System is available at no charge, so a developer can assess the engineering environment before choosing paid target software.
Watch out for
- Runtime software, device support, and optional engineering packages can have separate licensing; the free IDE alone does not establish a controller's deployment cost.
Best for
- PLC developers writing Structured Text, ladder, function-block, or sequential-function logic
- Industrial teams configuring and comparing controller projects across compatible devices
- Automation engineers who need project-level library reuse and online commissioning tools
Sources
- CODESYS Development System V3 | CODESYS Store International (Oct 26, 2026)
- Overview | CODESYS Development System Help (Oct 26, 2026)
- Creating and Configuring a Project | CODESYS Development System Help (Oct 26, 2026)