How to config an external encoder?

Hello  experts.

       Normally,when we config an external encoder,we need to assign it to a Drive.The encoder interface is:via PROFIdrice message frame.

       But now, i don't want to assign it to a Drive. The encoder interface should be : Acutal value via system vairable. How can i do ?

       Thank you very much.

Hello  experts.

      Thank you very much! but where to connect the system vairable?

thank  you very much .

     it says:"A position or velocity value can also be defined directly in a system variable
(sensorSettings.actualValue) from the user program"

      so  is that means iva program ?

      for example :encoder_1.sensorsetting.acutalvalue:="system viarable".

      is that right?