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. CODESYS 2.3.9 vs. CODESYS V3 – Which to Download? If you are starting a new project, do not use 2.3.9. Instead, download the latest CODESYS V3.5 (free for programming). However, here is a quick comparison:
If you are unable to locate the installer through official channels, the next best step is to contact your PLC supplier’s technical support – they will often provide the exact V2.3.9 version that matches your controller’s runtime.
Introduction In the rapidly evolving world of industrial automation, newer is not always better. While CODESYS (Controller Development System) has released modern versions like V3.5 and V3.5 SP19, a significant portion of the manufacturing sector still relies on older, proven systems. Among these, CODESYS 2.3.9 stands out as a stable, reliable workhorse.
| Problem | Solution | |---------|----------| | | Run in compatibility mode: Right-click setup → Properties → Compatibility → Windows 7. | | Gateway service fails to start | Open Services.msc → Find “CODESYS Gateway” → Set to Automatic → Start manually. | | Cannot find target device | Download the specific “.TRG” (target file) from your PLC manufacturer’s site and place it in \CODESYS V2.3\Targets . | | Visualization flickers | Disable hardware acceleration in the IDE settings. | | License lost after reboot | Run as Administrator once to register license dongle emulation (if using demo mode). |
| Feature | CODESYS 2.3.9 | CODESYS V3.5+ | |---------|---------------|----------------| | | ~2008 | 2013–present | | IEC languages | All (IL, ST, FBD, LD, SFC, CFC) | All + OOP extensions | | 64-bit support | No | Yes | | Modern hardware | Limited (legacy only) | All new PLCs | | Git integration | No | Yes | | Security | No encryption | TLS, user management | | Best for | Maintain old machines | New development |
