When the section must drop into an existing PROFINET line with wired safety

The 6SL3520-2XC01-1AB0 is the standard PROFINET variant for conveyor zones already covered by a hardwired STO loop - it communicates over PROFINET like every other 2XC unit while STO runs on the F-DI terminal.

Is the AB0 different from the AA0 in this power?

Both are standard PROFINET without PROFIsafe; they are distinct order codes within the 1.1 kW class. Performance is identical at 6.2 A - pick the one your regional stock or wiring option calls for.