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Seamlessly integrated communication protocols

The core task of CODESYS is the simple programming of logic controllers according to IEC-61131-3. In addition, the automation software offers extensive support of communication protocols for data exchange with other systems in the automation landscape.

All controllers communicate in real time with connected field devices, such as sensors and actuators. For this purpose, all important fieldbus and Industrial Ethernet systems are implemented in CODESYS. These products can be found in the category CODESYS Fieldbus.

In a connected Industry 4.0 architecture, modern controllers also exchange their information with other systems. These can be other controllers, but also any other intelligent devices in the controller network, connected MES or ERP systems, and private or public clouds. CODESYS makes communication simple: with proprietary and standard protocols that are seamlessly integrated into the platform:

  • As components in the CODESYS Control runtime system, which means they are firmly integrated in the control system
  • As components of the CODESYS Development System or as extension APIs
  • As reloadable libraries that are compiled along with the application code of the logic controller for the respective target device and executed there.

Your advantages

  • You only use tested and approved products you can rely on. Sample projects make it easier for you to use communication.
  • You can access the physical interfaces available in the device directly from the PLC application, e.g. Ethernet, serial interfaces, or controller I/Os.
  • You can exchange data directly with the most important communication protocols - via OPC UA as well as MQTT or http/https.
  • You integrate the protocols implemented as a library into your application. Such protocols, which you do not use, do not occupy any resources on the controller.
  • Using the possibilities of a modern programming tool (IDE), you can create and use your own protocols directly in CODESYS - without any external software environment. You can even offer the libraries developed in this way to other users via the CODESYS Store.

How can you obtain CODESYS Communication?

You are a system integrator or a user in the machine/plant construction sector or the like: Use controllers that are already equipped with integrated CODESYS communication protocols. 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. Alternatively, you can use the CODESYS Control SoftPLC systems from the CODESYS Store, which already implement a number of protocols. In the CODESYS Store, you will find numerous libraries for extending the pool of integrated communication protocols.

You are a manufacturer of programmable devices: Implement in your devices the required communication components of the CODESYS Runtime Toolkit as well as the possibility to license libraries per device.


CODESYS offers seamlessly integrated communication protocols for a wide variety of interfaces and requirements.

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OPC Server

Standard Interface to access the IEC 61131-3 process data of a controller via Open Platform Communications.

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Standard Interface for Communication in Smart Factory and Industry 4.0 Systems

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Compact software interface (API) for easy access to the PLC variables in CODESYS controllers from external systems

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Configurator and protocol stack fully integrated in the IEC 61131-3 Development System

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Serial interfaces

Although today almost every industrial controller has an Ethernet connection, serial interfaces are still installed in many industrial devices. This allows, for example, for the connection of appropriately equipped sensors and actuators or extensions.

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Standard Ethernet

How does CODESYS communicate via Ethernet? How can I send and receive data from a CODESYS-compatible PLC via TCP or UDP? How can I realize data exchange from the PLC application?

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Fieldbus systems and Industrial Ethernet

Sensors and actuators/actuators for processing control tasks can be separated from the controller via fieldbus and Ethernet systems with industrial communication protocols.

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IIoT libraries

All IoT communication protocols can be implemented and used on different transmission media via software.

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Other communication options

If a physical port is available on a controller, communication protocols can usually be implemented simply via software, either as part of the IEC 61131-3 control application or as separate library modules. Data exchange is performed by explicitly calling functions or function blocks as part of the logic control.

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Proprietary communication protocols

CODESYS supports the most common standard communication protocols for data exchange between controllers, such as OPC UA. In addition, Ethernet-based fieldbus systems such as PROFINET or EtherNet/IP™ make it easy to exchange data between controllers by implementing master and slave functions.

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