I'm going to assume you are talking about RSView ME runtime program where you can turn a computer into an HMI and "run-only" compiled programs. This allows you to run RSView ME programs on computers and you only pay for the licenses by the amount of screens in the project.
If you are using PanelView Plus, the Machine Edition run-time image is embedded into the terminal already. The only time you need an ME runtime station is if the app is going to run on a PC and not a PV+ terminal.
1. "RSView ME Station" is the run time only package.
2. "RSView Studio ME" is the editing package that allow limited time runtime testing.
3. Panelview + is basically a LCD Screen + PC that got "RSView ME Station" pre-installed.