Visilogic ((link)) May 2026

Many legacy VisiLogic customers remain because migrating a complex program to UniLogic requires complete rewriting. VisiLogic occupies a unique place in automation history: the first mainstream IDE to fully merge PLC logic and HMI design into a single, cohesive environment. For nearly two decades, it enabled small and medium automation projects to be completed faster and cheaper than separate PLC+HMI solutions. Its flat memory model, simple debugging, and offline simulation made it accessible to technicians without computer science backgrounds.

| Feature | VisiLogic | UniLogic | |---------|-----------|----------| | Data types | Flat operands (MI, ML, MF) | Structured variables (tags) | | UDFB | No (only subroutines) | Yes, with local variables | | HMI | Pixel-based, fixed resolution | Vector-based, scalable objects | | Ladder + ST | Separate rungs | Unified editor, ST in ladder actions | | Debugging | Watch window, trend | Live debug with tag browser | | Target | Vision series (obsolete) | Unistream (current) | visilogic

| Limitation | Consequence | |------------|--------------| | No object-oriented programming | Code reuse is copy-paste subroutines | | No structured data types (structs) | Complex data requires many parallel arrays | | Limited ST performance | ST mainly for math, not main logic | | Monospaced, fixed-size HMI fonts | Poor multilingual support (no Unicode) | | Maximum program size 512 KB Ladder | Large applications must be stripped down | | No native web server (older models) | Remote HMI requires third-party VNC | | No version control integration | Binary project files (.vlp) difficult to diff | | Windows-only IDE | Cannot run natively on Linux or macOS | Unitronics now promotes UniLogic for new designs. Key differences: Many legacy VisiLogic customers remain because migrating a