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 master/slave or client/server architecture. CODESYS offers extensive and integrated support.

Scope of services

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

If the libraries for master and slave 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. Check the CODESYS Device Directory for the devices best suited for your specific needs.
    On some of the devices without CODESYS Modbus support, CODESYS Modbus TCP Master SL, CODESYS Modbus TCP Device SL, CODESYS Modbus Master (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 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