Hi,

I'm not sure if I right understood your question. in a simple way:

• WinCC Unified RT means RunTime = it is responsible to "run" the user's project application.
• WinCC Unified ES means EngineeringStation = it is the plataform where the user develop your applicaiton.

Both could (or not) run in the same PC and have different licenses.

For example, a machine builder, has a development team that uses ES and when he delivery the machine, they are send with RT version.