The serial Protocol with Stack and Configurator, fully integrated in the IEC 61131-3 Development System

Integrated Modbus Support in CODESYS

The Modbus communication protocol is based on a client/server architecture. CODESYS offers extensive and integrated support.

Scope of services

  • generic Modbus configurator
  • protocol library for Modbus RTU Client and Server applications (serial communication)
  • protocol library for Modbus TCP Client and Server applications (Ethernet-based communication)

If the libraries for client and server communication are available and licensed for a controller, data communication can be established very easily. These libraries contain the implementation of the protocol stack in the form of platform-independent IEC 61131-3 code – they are compiled and linked with the application.


  • You are a system integrator or a user in the machine or plant construction sector or the like:
    Use controllers equipped with CODESYS Modbus TCP/RTU support. Millions of CODESYS-compatible single devices and over 1,000 different device types from more than 500 manufacturers offer you a large range of hardware for your automation projects. CODESYS Inside offers a selection of manufacturers that offer CODESYS-compatible devices.
    On some of the devices without CODESYS Modbus support, CODESYS Modbus TCP Client SL, CODESYS Modbus TCP Device SL, CODESYS Modbus Client (RTU) SL or CODESYS Modbus Serial Device SL can be subsequently licensed if required. Alternatively, you can use the CODESYS Control SoftPLC Systems from the CODESYS Store. CODESYS Modbus TCP/RTU is integrated in these systems as of license class "Basic M" and can be used immediately.
  • You are a manufacturer of programmable devices:
    Implement the CODESYS Modbus TCP/RTU support on your hardware. All you need for this implementation is the CODESYS Runtime Toolkit with Modbus TCP/RTU support. Alternatively, you can enable the option of licensing single licenses (SL) on your devices. This allows the users of your devices to license the CODESYS Modbus products SL on their part if required.
  • For more information or an offer please contact our sales department under


CODESYS brochures and information material

CODESYS - One software. All applications. Your Automation Solution.
Version: 10/2023
pdf 2 MB
CODESYS - One software. Any field of application. Your automation platform.
Version: 10/2023
pdf 2 MB
Various suppliers present CODESYS-compatible devices and exciting solutions that can be useful for your automation tasks. (Only available in german language.)
Version: 11/2022
pdf 3 MB