How many different robots (physical units, NOT model types) were sent back in time in the entire Terminator franchise?
The count should encompass ALL franchise works, not just the movies.
While I'm most interested in the final count, if you can please post either a list netting to that count, or a link to external source with such a list. This is so that the answer can be adjusted in the future if the franchise adds more works.
NOTE: I'm not aware if such a situation ever arose, but if it did, the same robot's physical body sent back >1 time only counts once. This includes even if it was sent again after being completely re-programmed from original traveled program.