As a last resort, the Internet Archive has snapshots of the old CODESYS FTP server. Use with caution – verify file hashes (MD5/SHA256) if available.

Search for "CODESYS V2.3" in the store search bar.

You do not need physical hardware to test your code. The software features a built-in PLC simulator that mimics logic behavior right on your engineering PC.

The project uses specific PLC hardware definitions not included in the base download.

Despite its age, CODESYS 2.3.9 supports all five IEC 61131-3 programming languages:

software, which is based on CODESYS 2.3, specifically for their 750 Series controllers. Eaton (XSoft-CoDeSys) : Eaton offers specific service packs, such as V2.3.9 SP5

To guarantee that future Windows updates won't break your development environment, build a clean Windows 7 Pro (32-bit) Virtual Machine (using VirtualBox or VMware). Install CoDeSys 2.3.9, your specific targets, and communication drivers inside this VM. Save the VM state as an immutable backup. Upgrading from V2.3.9 to CoDeSys V3.5

Supported on Windows XP/7/8/10/11 (32/64 Bit).

For more information on CODESYS 2.3.9, please refer to the following resources:

If you’re looking to get your hands on the installer, the "wild west" of the internet isn't always your friend. Here is the professional way to source it: The CODESYS Store: Always check the official CODESYS Store

Many engineers install CODESYS 2.3.9 inside a Windows 7 virtual machine (VMware or VirtualBox). This isolates it from modern OS conflicts and preserves settings for years.

Many robust PLCs and controllers still in production or active service use the CoDeSys V2.3 runtime engine. Upgrading to V3 is often impossible due to hardware architecture constraints.

If you cannot connect to the PLC, try reinstalling the CODESYS communication drivers ( setup.exe usually offers a "repair" or "reinstall drivers" option). Conclusion

Features include online tracking of variable values, forced variables, continuous sampling trace buffers, and breakpoints for precise troubleshooting.