No account, no download
Free PLC, CAD and SCADA software, in a browser
Four tools that open and work: a ladder editor with a scan-accurate PLC simulator, CAD for panel drawings and schematics, an HMI and SCADA builder with no tag limit, and a converter to Structured Text and SCL. No sign-up, no installer, no trial period, nothing that expires.
What "free" usually means in this industry
It is worth being specific, because the word is doing a lot of different jobs. Some tools are free forever and open source. Some are thirty day trials. Some give you a free editor and a runtime that stops after two hours. Some are free up to a tag count chosen to sit just below what a real machine needs. Some are free for personal use and licensed the moment the drawing is for a client.
All of those are legitimate. The problem is finding out which one you have after an evening's work. So here is which one this is, per tool, including what an account adds.
Ladder editor and PLC simulator
free PLC programming software, online PLC simulatorDraw ladder logic and run it. The simulator keeps a real output image, holds edge memory per instruction and counts timers in milliseconds rather than scans, so a rung behaves the way it would on a controller rather than the way a teaching tool pretends.
- Free
- Everything. Twenty three instructions, the tag table, the simulator, export.
- An account adds
- Saving to a project rather than to this browser, and AI generation.
CAD for panels and schematics
free online CAD, free electrical CAD softwareTwo dimensional drafting for the electrical and panel drawings an automation project produces. Eleven templates numbered the way a control package is read, typed commands, object snap, dimensions, named layers.
- Free
- The whole editor, and DXF and SVG export, so nothing is trapped here.
- An account adds
- Drawings that follow you between machines, filed against a project with its title block filled in.
HMI and SCADA builder
free SCADA software, free HMI softwareOperator screens with eighty seven symbols and alarms following the ISA-18.2 state machine. It binds to the ladder editor's own tag table and runs against the same scan engine, so a start button on the glass starts the motor in the logic.
- Free
- The builder, the symbols, the alarms, the runtime, and no tag limit.
- An account adds
- A project to file it against, and drawing a screen from a description.
Ladder to Structured Text and SCL
convert ladder to structured textWrite a ladder program out as IEC 61131-3 Structured Text, Siemens SCL, Rockwell neutral text or PLCopen XML, with a report of what converted cleanly and what did not.
- Free
- All four outputs and the conversion report. It runs in the browser, so the program does not leave your machine.
- An account adds
- Nothing. This one is the same either way.
Questions
- Is this actually free, or is it a trial?
- Free with no time limit. There is no trial period, no watermark, no tag count and no export paywall on any of the four tools. An account adds somewhere central to keep work and AI generation, which needs a provider key that belongs to a person.
- Do I need to download or install anything?
- No. All four run in the browser. Work is saved in the browser, which means clearing your site data clears it, so export anything you want to keep. There is also a desktop build for sites that will not allow a cloud tool at all.
- What is the catch?
- Two honest ones. Anything using a model needs a provider key you supply, because there is no shared inference key and no metering here. And none of these deploy to hardware: they design, simulate and document, and downloading to a controller or a panel is a deliberate act with the vendor's own tools.
- How does this compare to OpenPLC or CODESYS?
- Different jobs. OpenPLC is a real runtime you can put on hardware; CODESYS is a full IEC engineering environment with a free editor and a runtime that stops after two hours. These tools install nothing, expire never, and are for drawing, proving and documenting rather than for running a machine.
- Can I use this commercially?
- Yes. There is no personal-use restriction and no licence that changes when the drawing is for a client.
Also free, and not software
Seventeen automation project document templates, downloadable without an account, and a hundred articles on the things that get asked every week: scan cycles, timers, analogue scaling, functional safety, alarm rationalisation and the rest.