Which Modbus transports are supported?

Modbus TCP and RTU over TCP through an Ethernet gateway, and Modbus RTU over a local serial port such as /dev/ttyUSB0 or /dev/ttyS1, with configurable baud rate, parity and stop bits.

Do I have to edit configuration files?

No. Gateways, devices, registers and the broker are all set up in the web interface. The configuration lives in a local SQLite database and can be exported to a single JSON file.

Can I control devices from MQTT?

Yes. Read-write channels have a command topic — {topic}/set by default. A value published there is written to the register, and commands take priority in the polling queue.

What hardware does it run on?

Any Debian or Ubuntu machine, from a home server to a Raspberry Pi. Builds exist for amd64, arm64 and armhf; the service is small and pulls in no dependencies.

Will it work with Home Assistant?

Yes. It publishes to an ordinary MQTT broker, so Home Assistant picks the topics up through its MQTT integration, and Node-RED or OpenHAB read the same topics.

How many devices can one instance poll?

The limit in practice is the bus, not the software. RS-485 tolerates a few dozen devices per segment, and the poll interval decides how quickly each one comes round. Several gateways are polled in parallel.

ELX-MODBUS

Download

Direct links, no registration and no download manager. Files are served straight from the site.

v1.2.38 2026-08-27 Free

Debian package for amd64 — ordinary PCs and servers elxmodbusmqtt_1.2.38_amd64.deb amd644.6 MB Debian package for arm64 — Raspberry Pi 3, 4 and 5, 64-bit elxmodbusmqtt_1.2.38_arm64.deb arm644.3 MB Debian package for armhf — 32-bit ARM boards elxmodbusmqtt_1.2.38_armhf.deb armhf4.4 MB

Release details

Version: 1.2.38
Released: 2026-08-27
Built with: Go
License: Free for any use

Full documentation

Nearby programs

ELX-MQTT Broker A complete MQTT broker with a live web dashboard v1.0.39 ELX-Serial One serial device, several network clients v1.6 ELX-Terminal A terminal for COM ports, raw TCP and TCP through an SSH tunnel v1.0.0