System redundancy with RFC 4072R

Available from 2022.0 LTS

The RFC 4072R is a high-availability PLCnext Control with redundancy functionality. Some commissioning steps differ from those of other PLCnext Control devices. In the course of the system redundancy with RFC 4072R, we describe only these differences.

Creating a new RFC 4072R project

  • In PLCnext Engineer software, open the FileNew Project menu.
  • If this is your first RFC 4072R project with the PLCnext Engineer installation in use, you need to import the High-availability Controller libraryimport the High-availability Controller library  first.

    To be able to insert the RFC 4072R as a controller in the PLANT area, you first have to import the High-availability Controller library in the COMPONENTS area:

    • In the COMPONENTS area, open the Libraries (x) section (where the x is the number of libraries you have there already).
    • Click on Libraries (x) folder with the right mouse button.
    • Select Add Library... from the context menu.
    • In the Windows file explorer dialog that opens, select the High-availability Controller.pcwlx library and click Open.

    The device information for the RFC 4072R will be made available in the COMPONENTS area of PLCnext Engineer.

  • In the COMPONENT area, open the section Network → High-availability ControllerDevicesPhoenix ContactRemote Field ControllerHigh-availability Controller → RFC 4072R.
  • Drag and drop the RFC 4072R to the Project node of the PLANT area and save the project.

You have created an empty RFC 4072R project.


Before programming, proceed setting up the redundant controllers by

Creating tasks

Different from the usual procedure is that you may use only one cyclic task and up to five event tasks for a redundant system.
In redundancy mode, the cyclic task is synchronized between the controllers. Event tasks are not synchronized in redundancy mode.

Note: The cyclic task must be named SyncTask  to be synchronized between the controllers in redundancy mode.

For further steps, see Instantiating a program.




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• Published/reviewed: 2022-09-14 • Revision 046 •