Modbus Protocol

Owned by Franck Arthur Kapche Simo
Last updated: Mar 04, 2020 by Fabio De Riccardis
2 min read

Modbus is a communication protocol originally published by Modicon (now Schneider Electric) in 1979 for use with its programmable logic controllers (PLCs). Modbus has become a factory 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 protocol and Teltonika

Teltonika supports two types of modbus Protocol:

  • Modbus TCP/IP or Modbus TCP : This is a Modbus variant used for communications over TCP/IP networks, connecting over port 502 (default port).

  • Modbus RTU (remote terminal unit): This is a serial communication protocol mainly used in communication via RS232 or RS485 serial interfaces.

The Modbus protocol work in two: Modbus Master and Modbus slave. A Modbus master device can request data from Modbus slaves.

The Modbus protocol module supports reading and writing to all valid Modbus registers from Modbus compatible devices.

Supported devices

Networks devices

All Teltonika routers and gateways has ModBus TCP master functionality to read data from other slave devices;

As of 2020-03:

  • RUT955, TRB142 and TRB145 can be used to read data via ModBus RTU, since they has ModBus RTU master functionality;

  • RUT955, TRB142 and TRB145 can read ModBus slaves data using ModBus TCP and ModBus RTU protocols;

You can have more information in the link below:

https://wiki.teltonika-networks.com/view/RUT955_Modbus

https://wiki.teltonika-networks.com/view/Monitoring_via_Modbus

Vehicles Telematics devices

As of 2020-03, FMB640, FM63 and FMB125 support RS485, therefore they can support MODBUS Protocol. But functionality it is not available, thus special development is required.