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

Standard Access to the Variables of a CODESYS PLC

OPC (Open Platform Communications) is a standard interface which provides access to the data of an automation process. Main task of the CODESYS OPC Server is the exchange of data (read / write) with the controller for example for visualizations or for process data logging programs. The CODESYS OPC Server is an additional Microsoft Windows program that is included in the setup of the IEC 61131-3 Development System CODESYS. To use it, licensing is required: Either via a USB dongle (CODESYS Key) or a so-called SoftContainer on the PC running the CODESYS OPC Server.

Supported specifications

  • OPC Common Definitions and Interfaces Version 1.0
  • Data Access Custom Interface Standard Version 1.0a
  • Data Access Custom Interface Standard Version 2.05A
  • Data Access Custom Interface Standard Version 3.0
  • Data Access Automation Interface Standard Version 2.02
  • Alarms and Events Interface Version 1.10
  • Hierarchical browsing of variables supported


  • is part of the standard setup of the CODESYS Development System but requires a USB dongle license for usage
  • comprises the server, a server configurator and a logger (for debugging)
  • requires a symbol configuration in CODESYS with the data to be exported
  • can be connected to controllers programmable with CODESYS V3 or CODESYS V2.3
  • is certified by the OPC Foundation

Features and Functionality of the CODESYS OPC Server

  • Automatic start upon establishment of a client connection
  • Automatic trigger when a data value or a data status changes (OPC items)
  • Browsing the variable list (item pool or address space)
  • Managing the items in the data cache
  • Direct access to items in the controller possible (without cache)
  • Organization of the items in groups (private or public)
  • Optional integrated data logger for diagnostics
  • Multi-client support and multi-PLC support
  • OPC connection also possible to controllers with CODESYS V2.3
  • Included in the setup of the IEC 61131-3 programming environment CODESYS Development System. Requires licensing via the CODESYS Store

Using the CODESYS OPC Server

  • Development of the IEC 61131-3 project in CODESYS
  • Symbol configuration: Creation of the object in the application and selection of the variable values to be exported for the exchange of data via OPC
  • Configuration of the CODESYS OPC Server for the connection to the desired controller using the configuration tool
  • Login to the controller, download and execution of the PLC application
    ⇒ Automatic provision of the configured symbols via the CODESYS OPC Server
  • Start the OPC client and establish connection to the CODESYS OPC Server 
    ⇒ Automatic start of the CODESYS OPC Server 
    ⇒ Browse / use the item pool


The CODESYS OPC Server is available as standalone setup or as a part of the 32-bit setup of the CODESYS Development System.

The current version of the OPC Server Setup or the CODESYS Development System can be downloaded free of charge from the CODESYS Store after registration.

In order to use the OPC server, a license is required, which is stored on a USB-Dongle (CODESYS Key) or directly on the PC running the CODESYS OPC Server. Licenses and CODESYS Keys can be purchased at the CODESYS Store.

For more information please contact our sales department under

CODESYS brochures and information material

CODESYS - One software. All applications. Your Automation Solution.
Version: 11/2021
pdf 2 MB
CODESYS - One software. Any field of application. Your automation platform.
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