First of all sorry for the late reply!
About the difference between stopper and separator: There is a mechanical difference between the two. A separator consists of two pins working together like a rocker. That way the timing is less relevant and it is always guaranteed exactly one carrier passes the separator when moving it back and forth once. A stopper is just one pin that allows any number of carriers to pass through while it is open.
About the documentation: Thanks for the hint. We will fix this translation error in a future version. "Query" should just be carrier detection (by the SAt/SOn sensor).
There is no way to let this object automatically handle the separation without starting any command. But there is an alternative approach: The objects belonging to the transfer system (i.e. the NexeedTrs... objects) are designed for automatic wpc handling based on standardized transfer node types.
Now about PKlein's answer: I am sorry I have to disappoint you, but there are no activities going on concerning this object. A colleague does remember there were some discussions about the object, but there has never been a commitment to start any development. This must be a misunderstanding. If you have any specific requirements, please contact the helpdesk.