Ladder Logic Editor
Ladder Logic was always planned as the main language at rungs.dev (hence the name). It wasn't my first choice for the MVP because building such an editor takes a lot of effort, and Monaco is readily available. Structured Text was a reasonable choice to ship quickly.
PLC Simulator Online
Another reason I started with Structured Text is that I didn't want rungs.dev to compete with my other project - PLC Simulator Online.
rungs.dev Studio is a different product. It's focused on AOI-style development: tags, tests, simulation, trends, and versioned .rungs files. Starting with Structured Text let me ship that core workflow first, then return to Ladder with a clearer scope.
In the long term, I hope rungs.dev Studio will replace PLC Simulator Online. PLC Simulator Online will continue to be available as a mobile alternative.
Survey results
For the past three weeks, we've been running a survey asking, "Which PLC language do you want to practice?" The vast majority of you answered Ladder Logic, so the next feature I'm working on is a Ladder Logic editor.
131 total votes.
What Ships First
Planned for the first release:
- Rung editor, single-level and multi-level branches
- Basic instructions: contacts and coils
- More instructions: timers/counters, math/compare, one-shots
- Editing: selection, drag/drop
- Execution: in-browser simulation with contact/coil highlighting and integer value updates
What's Next
After the basics are stable:
- Addressing: bind instructions to existing tags, create tag from editor
- Comments: rung comments, instruction labels, documentation-first workflows
- Editing: copy/paste, undo/redo
Feedback
If you use Ladder daily, tell me which instructions you'd like to see next.
Share feedback via the survey.