rungs.dev

dev provides a browser-based environment for designing, simulating, and testing programmable logic controller (PLC) programs using both Ladder Logic and Structured Text. The platform eliminates the need for installing traditional PLC software, making it accessible directly from the web for users interested in learning, teaching, or refining PLC logic. It is intended for those who want to practice PLC programming, prototype control logic, or refresh their skills without hardware or expensive software.

dev is Relay, an integrated AI assistant that analyzes users' actual logic, tags, and tests within Rungs Studio. Relay can answer questions about rung behavior, compiler warnings, and next steps in building logic, providing targeted guidance based on the user's real project. The Ladder Logic editor offers a visual drag-and-drop interface, supporting standard instructions such as XIC, XIO, OTE, timers, counters, and math operations, all rendered as ladder diagrams. The Structured Text editor includes syntax highlighting, instant error feedback, and supports constructs like IF/THEN, CASE, FOR, and WHILE.

The tool also features comprehensive tag management, allowing users to define tags with full data type support (including BOOL, DINT, REAL, and arrays), assign usage roles (Input, Output, or Local), set default values, and add descriptions. Real-time simulation capabilities enable users to run, pause, resume, stop, or step through PLC programs scan by scan, with visual signal flow highlighting logic continuity. An integrated test runner allows for automated testing of Add-On Instructions (AOIs), running each test in an isolated scan cycle for deterministic and repeatable results. Built-in trend analysis charts visualize PLC tag values over time, helping users monitor and debug process behavior.

rungs files for sharing and version control, and emphasizes professional-grade, reusable logic suitable for real machine control. The platform is developed by Techsolid Automation Limited.