Welcome to modpoll2mqtt’s documentation!

modpoll2mqtt is a command-line Modbus-to-MQTT gateway. Install it with pip install modpoll2mqtt and run the modpoll command.

It polls Modbus devices (RTU, TCP, UDP) using CSV configuration files, publishes values to an MQTT broker, and supports semantic write commands by CSV reference name.

Contents:

• Installation
  • Install with pip or pipx
  • Uninstall
• Quickstart
  • Poll once
  • Publish to MQTT
  • Write by reference
• Basic Usage
  • Named Arguments
  • Commandline Usage
  • Configuration sources
  • Export
  • Operational flags
  • Configuration File
  • Framers and transports
  • Persistent Modbus connection
  • MQTT retain
  • MQTT status
  • MQTT diagnostics
  • MQTT payload keys
  • MQTT single publish
  • Publish behavior
  • MQTT write commands
  • MQTT on-demand read (get)
• Configuration
  • Modbus configure file
  • Example 1: Modsim device (Modbus TCP device)
  • Example 2: SCPM-S6 Power Meter (Modbus RTU device)
• Changelog
  • 2.2.1 (2026-06-16)
  • 2.2.0 (2026-06-16)
  • 2.1.2 (2026-06-15)
  • 2.1.1 (2026-06-11)
  • 2.1.0 (2026-06-10)
  • 2.0.0 (2026-06-10)

Indices and tables

• Index

• Module Index

• Search Page