Vendor-neutral · validated · runs offline
Ladder logic you can
actually run.
LADX is a web workbench for PLC and automation engineers: ladder logic with a scan-accurate simulator, HMI screens, panel drawings and engineering documents on one project. Draw a rung and watch it conduct. Ask for logic and get it checked, with every problem shown rather than hidden.
No account, no card. It runs in the browser and saves to the browser.
Click the contacts on the rung, or the switches below. Press Start and the conveyor latches through its own contact and stays on when you let go. Stop is normally closed, so it conducts at rest and breaks the rung when pressed.
Every vendor built a copilot.
Every one of them is a cage.
Siemens will help you write Siemens. Rockwell will help you write Rockwell. Beckhoff will help you write Beckhoff. That is not a criticism. Their assistants exist to sell their hardware, and they do it well.
It leaves out the person who touches a Siemens line, a Rockwell cell and a CODESYS skid in the same week. Which is most system integrators, most contractors, and most maintenance departments in a plant that has bought equipment for more than ten years.
LADX belongs to the engineer instead of to the hardware.
How it works
Nothing reaches you unchecked
A language model that has read the internet can write something that looks like ladder logic. Looking right is not the bar in a job where wrong code stops a line, or hurts somebody. So LADX checks every answer and puts what it found next to it.
Ladder is checked before it lands
Generated rungs go through the editor's own validator and a seal-in check before they reach the canvas. Whatever either objects to is listed, never hidden.
Structured Text is checked as it arrives
Every block is checked for unclosed blocks and unbalanced brackets the moment it appears. It is a structural check, not a full compiler, and LADX says so.
Errors go back on one click
Auto-fix hands the checker's own errors back to the model, up to three times, and shows you each attempt. That is what makes a free model good enough to be useful.
What's in it
Ten tools that share one project
They are not separate apps that export to each other. They all read and write the same representation, so the rung you draw is the rung the AI edits, the rung that converts, the rung Monitor runs, and the rung that ends up in the functional spec.
Write the logic
Draw it, ask for it, move it between platforms.
Ladder editor
Available nowDraw a rung. Press run. Watch it conduct.
A ladder editor with a real scan engine behind it. It is the canvas the AI writes onto, it opens on your own programs rather than an empty grid, and it works entirely in the browser with no account and no backend.
Chat
Available nowAsk for logic. Get it checked.
Describe what the machine should do and watch the rungs appear on the canvas. Every answer is checked before you work with it, and whatever the checks object to is listed beside it, never hidden.
Convert
Available nowBetween platforms, and between languages.
Take a program you have drawn or saved and write it out as IEC 61131-3 Structured Text, Siemens SCL, Rockwell neutral text or PLCopen XML. Every conversion comes with a report of what moved cleanly and what did not, and it all runs in your browser without uploading anything.
Draw it and prove it
The panel drawings, and the logic running.
CAD
Available nowThe panel drawings, on the same project.
A drafting tool that opens on a finished sheet rather than an empty one. Eleven working templates numbered the way a control package is read, thirty-four typed commands, object snap, dimensions, and DXF both ways.
HMI builder
Available nowThe operator screens, on the same tags.
An HMI builder for operator and SCADA screens that binds to the ladder program's tag table rather than a second one kept in step by hand. Pick the panel, draw the mimic, define the alarms, and press run: the same scan engine that drives the simulator drives the screen.
Monitor
Available nowRun the logic and watch it move.
Take any program you have saved, run it at scan speed, force the inputs and watch the tags change. A bench test you can do before anybody books the panel shop.
Ship the project
The job around the code, and its paperwork.
Projects
Available nowThe job around the code.
A project holds the design basis, the drawings, the programs and the documents, and it knows which phase of the job it is in. The plan comes from the lifecycle rather than from a blank page.
Planner
Available nowEvery project on one timeline.
A Gantt chart over every project at once, seeded from the deliverables each job actually owes. Drag a bar to move it, drag its edge to change how long it takes, and let a dependency stop a task starting before the one it waits on has finished.
Documents
Available nowThe paperwork a project actually produces.
Seventeen working templates across specification, design, registers, safety, testing and handover, with the tables and sign-off blocks already in them, filled from your project rather than typed a second time.
Knowledge
Available nowYour manuals, answering questions.
Drop in the drive manual, the machine spec, the site standard. Ask questions against them and get answers with the page they came from.
Why conversion works
Every format meets in the middle
There is no Siemens-to-Rockwell converter inside LADX, and there never will be. Everything is read into one representation built on PLCopen TC6, and everything is written out of it.
Four importers and four exporters give sixteen conversion paths for eight pieces of work: and adding a ninth vendor gives everyone else a new destination for free.
Also, it teaches
The simulator does not lie to you
Most teaching simulators cheat: they solve the rungs like a list of equations, so a coil on rung five appears to reach a contact on rung two instantly. Then the student meets a real controller and nothing behaves the way they were taught.
LADX keeps the output image. A coil written after a contact has already been solved does not reach it until the next sweep. Edges are remembered per instruction, so a held button counts once and not four thousand times. Timers advance on elapsed milliseconds, not on how many scans happened to fit.
Which is to say: the things students get wrong are the things it gets right.
Open it and draw a rung.
The editor and the simulator are free and always will be. No sign-up, no card, nothing to install.
Open the ladder editor