plasmaweb - a browser-based QtPlasmaC screen for LinuxCNC

Hi everyone!

This is my first post here, so a quick introduction. I'm Ruben, a web developer from Melbourne, Australia, who loves building CNC machines. I've been reading this forum for a while as I plan and build my first plasma table. Along the way, I wanted to drive the machine from a touchscreen, a laptop or my phone rather than a screen bolted to the controller. So I built a web interface for QtPlasmaC, and I'd like to share it.

Important: this has not been tested in production yet. My table is still being built, so plasmaweb has only been run against a virtual LinuxCNC machine — the QtPlasmaC simulator config on LinuxCNC 2.9.4, running in a VM — not on a real machine cutting real metal. Please treat it as untested on hardware, try it on a sim config first, and keep a working QtPlasmaC config to go back to (switching back is one INI line, see below). Bug reports and feedback are very welcome.

What it is

plasmaweb replaces the QtPlasmaC screen, not your config. It runs as the LinuxCNC [DISPLAY] program: a Python backend on the controller serves a touch-friendly web UI, and you open it in a browser on the controller itself or on any other machine on your network.It is designed as a drop-in:

• It registers the same qtplasmac HAL component (same 91 pins) that QtPlasmaC does, so your existing postgui HAL files connect unchanged.
• It reads and writes the same files: <machine>.prefs, <machine>_material.cfg and the [QTPLASMAC] INI section.
• Switching over is one line in the INI (DISPLAY = plasmaweb). Setting it back to qtvcp qtplasmac returns the machine to QtPlasmaC.

All reactive and timing-critical logic stays in the realtime plasmac component. The web UI is a dashboard and remote control only: it writes setpoints and one-shot requests, and pins owned by the realtime side are read-only to it. Losing the browser or the network connection never changes machine state.

Features

Plasma screens (mirroring QtPlasmaC's tabs)

• MAIN — live dashboard: arc voltage, THC state, status LEDs, cut recovery, torch pulse, height override, single cut
• PARAMETERS — the QtPlasmaC parameters, saved back to your .prefs file, with QtPlasmaC's own tooltips
• MATERIAL — materials from your _material.cfg, including the M190 material-change handshake
• CONVERSATIONAL — LinuxCNC's own plasmac shape modules, driven from a web form
• PREVIEW — toolpath preview and run-from-line
• STATISTICS — cut counts, arc time and consumable stats

General machine control

• Jogging, homing, MDI, program load/run and the tool table
• Macros, HAL softkeys and external panel inputs
• Uses your machine's own QtPlasmaC colours and keyboard shortcuts from the prefs file
• Layouts for 16:9, 4:3 and portrait (9:16) screens
• English and German UI

Remote access

• Open the UI from a laptop, tablet or phone on your network. Settings shows the address to type in.
• There is no authentication: anyone who can reach the port can jog the machine and fire the torch. Only use it on a network you trust, or set PLASMAWEB_HOST=127.0.0.1 to restrict it to the controller's own screen.

Built-in updates

• When the UI loads, it checks GitHub for a new release and offers Update now / Later / Skip this version. Settings → Updates shows the installed version and has a "Check for updates" button.
• Updates are downloaded over HTTPS and checksum-verified, and are refused while a program is running. Restart LinuxCNC afterwards to use the new version.

LinuxCNC versions: verified against the 2.9.4 simulator. Features that only exist on 2.10 (moving pierce, tube cutting, laser mode, slat height, offset feed rate) are detected from the pins your machine actually exports, and are shown as unavailable rather than as controls that silently do nothing.

Installing

No Node.js needed on the controller. Download the latest release tarball from GitHub and run the installer:

tar xzf plasmaweb-<version>-linux.tar.gz
cd plasmaweb-<version>-linux
sudo ./install.sh

Then in your machine INI:

[DISPLAY]
DISPLAY = plasmaweb

Full guide:   installation.md
Releases:   github.com/RubenAhlhaus/plasmaweb/releases
Source:   github.com/RubenAhlhaus/plasmaweb   (GPL-3.0-or-later)

Credits

This project stands on the work of others, and I want to credit them properly:

• lcncgui (  github.com/salomom/lcncgui  ) — the web application plasmaweb is built on. The backend, the WebSocket layer, and the jog, DRO, MDI, program and tool-table screens all come from lcncgui. plasmaweb adds the plasma layer on top. Huge thanks to its author.
• LinuxCNC and QtPlasmaC / plasmac — the realtime plasmac component does the actual work of running a plasma table, and plasmaweb reuses QtPlasmaC's conversational shape modules, run-from-line logic and G-code handling directly from LinuxCNC rather than reimplementing them. The whole design copies QtPlasmaC's files and HAL interface so that both screens stay interchangeable. Many thanks to Phillip Carter, Gregory Carl and everyone who has contributed to QtPlasmaC and LinuxCNC.

Feedback

If you try it on a sim, or are brave enough to try it on a real table, I'd love to hear how it goes. Please report issues on GitHub or reply here. Since I can't test on hardware yet, reports from people with working tables are especially valuable.Thanks for reading, and thanks to this community for everything I've learned here.