1. Introduction

RTI® Routing Service Modbus® Adapter is a plugin for RTI Routing Service that enables communication between Modbus and DDS applications.

Using Routing Service Modbus Adapter, Routing Service can act as a Modbus Client, connect to a Modbus Server, send requests to write or read holding registers and coils, or read input registers or discrete inputs.

You can configure Routing Service to route data between multiple DDS Domains and Modbus Devices.

This document assumes you have a basic understanding of the MODBUS protocol, DDS and Routing Service, and their terminology.

1.1. Modbus Registers and Addresses

Routing Service Modbus Adapter differentiates between a “register address” and a “register number”. Register addresses use a 0-based index; register numbers use a 1-based index.

Throughout this documentation, only “register address” is used. Therefore, code snippets and examples will consider the register 0 as a valid register.