Flash firmware to a USB-connected Waveshare / Prelude board — right here in the browser, no install. (Chromium desktop: Chrome / Edge.) Plug the board in over USB-C, then pick which firmware.
Turns the board into a read-only Modbus/serial bridge: the site talks to the board over USB, the board reads your real device over RS-485. This is what you want to READ a device.
Pick the ESP32-S3 (usbmodem / Espressif) port when asked. ~30s. When it finishes, go read your device →
Turns a SPARE board into a fake Acuvim-L power meter on RS-485 — it answers Modbus with live-varying values. Wire its A/B/GND to a reader (dongle or a second Prelude board) to test the whole read flow with no real meter. A board with this firmware is not a reader — re-flash the reader firmware above to turn it back.
Use a SEPARATE board for this — not the one you read with.
Flashing overwrites the board's existing firmware. Switch a board between reader and emulator any time by re-flashing.