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Creation of a root user

Every PLCnext Control is based on a Linux operating system and is delivered with a preconfigured admin user with a unique password.

With the admin user it is possible to get access to the most important functions (e.g. OpenVPN® and firewall configuration, set time and date, read/write project specific folders), but sometimes it might be necessary to get root permissions.

This can be done temporary by using the "sudo" command, but it is also possible to create a persistent root user.

Watch also our Tutorial Video on Youtube How to create a root user

With the permissions of the root user it is possible to perform changes to the operating system and to start/stop processes.
When using the root permissions it is the responsibility of the user to ensure and to test the stability of the system and application!
Phoenix Contact only guarantees the function in the context of the unchanged state of delivery of the firmware.

In case a C++ application also creates real-time tasks, the user is responsible for the specification of the priority and for the proper function of his application.
We strongly recommend to use only priorities lower than Prio 51, so that the tasks do not violate the real-time capability of the PLCnext Technology framework.


Create a root user as follows

  1. Establish a terminal connection with any given SSH client (e.g. WinSCP with Putty , How to use WinSCP)

  2. Login to the system as admin user:

    Using username "admin".
    This email address is being protected from spambots. You need JavaScript enabled to view it.'s password: *Enter here the unique admin password of the device on the printed on the housing*
  3. Create a new root user:

    admin@axcf2152:~$ sudo passwd root

    We trust you have received the usual lecture from the local System
    Administrator. It usually boils down to these three things:

        #1) Respect the privacy of others.
        #2) Think before you type.
        #3) With great power comes great responsibility.

    Password: *Enter here the unique admin password of the device on the printed on the housing*

    Changing password for root
    Enter the new password (minimum of 5 characters)
    Please use a combination of upper and lower case letters and numbers.
    New password: *Enter here the password of the root user*
    Re-enter new password: *Confirm the password*
  4. After the root user was created you can login as root user by using the command

    admin@axcf2152:~$ su -
    Password: *Enter here the password of the root user*
    root@axcf2152:~#  *You are now logged in as root user*