Template:Networking rut955 manual modbus serial

From Teltonika Networks Wiki

Introduction

Modbus is a serial communications protocol originally published by Modicon (now Schneider Electric) in 1979 for use with its programmable logic controllers (PLCs). Modbus has become a de facto standard communication protocol and is now a commonly available means of connecting industrial electronic devices. The main reasons for the use of Modbus in the industrial environment are:

  • developed with industrial applications in mind,
  • openly published and royalty-free,
  • easy to deploy and maintain,
  • moves raw bits or words without placing many restrictions on vendors.

Modbus enables communication among many devices connected to the same network, for example, a system that measures temperature and humidity and communicates the results to a computer. Modbus is often used to connect a supervisory computer with a remote terminal unit (RTU) in supervisory control and data acquisition (SCADA) systems. Many of the data types are named from its use in driving relays: a single-bit physical output is called a coil, and a single-bit physical input is called a discrete input or a contact.

This article provides an example on how to use Modbus serial to monitor a slave device and send data to server.

Prerequisites

  • One RUT955 router
  • Windows 10 computer
  • Hercules and modRSsim applications
  • RS232 to USB cable


Configuring Modbus serial slave device

In this example we are going to be using our Windows 10 computer as a slave. To do so you will need to download and install modRSsim application, which you can download here.