serial #

A browser tool for the RS-485/Modbus RTU bus this project's devices sit on, using the Web Serial API. It does two things a firmware build cannot:

• Watches the bus. Decodes the traffic between the fan controller and the fans without joining in, the way debug-listener does from the desktop — but framed and decoded rather than printed as bytes.
• Talks to a device directly. Reads input registers and reads and writes holding registers, which is how a device gets its address, baud rate and correction values set before it is wired in.

Only one of those at a time per port: watching is passive and polling is not, and a half-duplex RS-485 line has room for one master.

Running it #

cd serial && pnpm install && pnpm dev

pnpm test runs the protocol tests, pnpm check type-checks, pnpm build does both and produces dist/.

Deploying it #

.github/workflows/serial-pages.yml builds this directory and publishes it to GitHub Pages on every push to main that touches serial/. It runs the tests and the type-check first, and it runs on pull requests too without deploying.

Pages has to be switched on for the repository once before the first deploy: Settings → Pages → Build and deployment → Source: GitHub Actions.

The build sets Vite's base to ./, so the same dist/ works at a domain root and under the /<repo>/ path a project site is served from.

The Web Serial API is Chromium-only (Chrome, Edge, Opera) and needs a secure context, so localhost or HTTPS. The app says so itself rather than failing silently.

Layout #

Everything under src/modbus is plain TypeScript over bytes with no DOM in it, so it is tested directly with vitest. The tests are built on frames the manufacturers printed, which is the strongest check available: they agree only if this code agrees with the devices rather than merely with itself.

That is not hypothetical. The humidity frames in docs/temperature-sensor.md had wrong check bytes, and the test comparing them against crc.ts is what found it. Both are corrected there now.

Where the device documentation lives #

• RadiCal fans — docs/manufacturer/radical/, in the private submodule. The authority on register addresses, units and naming.
• Relay module — docs/manufacturer/relay/, same submodule.
• Temperature sensor — docs/temperature-sensor.md. No manufacturer PDF exists for it; that file is all there is.

The German terms in the RadiCal manual are the reference for what a register is called — Aussteuergrad, Wirksinn, Sollwert — rather than any translation invented here.

Stack #

SolidJS 2.0 (release candidate) on Vite, with pnpm. Solid 2.0 differs from 1.x in ways that matter when reading this code:

• createEffect takes two functions, a compute and an effect: createEffect(() => signal(), value => …). The single-argument form from 1.x is gone and is typed never.
• DOM rendering lives in @solidjs/web, not solid-js/web, and that is also the jsxImportSource.