RModBus

RModBus - free implementation of ModBus protocol in pure Ruby.

• Ruby 2.5+ and JRuby (without serial ModBus RTU)
• TCP, RTU, RTU over TCP protocols
• Client(master) and server(slave)
• 16, 32-bit and floating point registers

• Read Coils (0x01)
• Read Discrete Inputs (0x02)
• Read Holding Registers (0x03)
• Read Input Registers (0x04)
• Write Single Coil (0x05)
• Write Single Register (0x06)
• Write Multiple Coils (0x0F)
• Write Multiple Registers (0x10)
• Mask Write register (0x16)

Download and install RModBus with the following:

gem install rmodbus

Or if you are using bundler, add to your Gemfile:

gem 'rmodbus'

If you want to use ModBus over serial, you will also need to install the 'ccutrer-serialport' gem. If you are using bundler, add to your Gemfile:

gem 'ccutrer-serialport'

If you want to use ModBus::TCPServer or ModBus::RTUViaTCPServer, you will also need to install the 'gserver' gem. If you are using bundler, add to your Gemfile:

gem 'gserver'

Please note that GServer is deprecated, and I'm looking for a better solution. Contributions are welcome!

  require 'rmodbus'

  ModBus::TCPClient.new('127.0.0.1', 8502) do |cl|
    cl.with_slave(1) do |slave|
      # Read a single holding register at address 16
      slave.holding_registers[16]

      # Write a single holding register at address 16
      slave.holding_registers[16] = 123

      # Read holding registers 16 through 20
      slave.holding_registers[16..20]

      # Write holding registers 16 through 20 with some values
      slave.holding_registers[16..20] = [1, 2, 3, 4, 5]
    end
  end

This project will follow http://semver.org/

Given a version number MAJOR.MINOR.PATCH, increment the:

MAJOR version when you make incompatible API changes,
MINOR version when you add functionality in a backwards-compatible manner, and
PATCH version when you make backwards-compatible bug fixes.

See CONTRIBUTING.

RModBus on GitHub: http://github.com/rmodbus/rmodbus

Documentation: http://www.rubydoc.info/github/rmodbus/rmodbus

ModBus specifications: http://www.modbus.org/specs.php

BSD-3-Clause

Aleksey Timin - original author