The conveyor zone that just died was sized for 1.5 kW, the controller drives it over plain digital I/O, and nobody wants to touch the PLC program just to swap a drive. 6SL3520-2XH01-5AB0 is that replacement: the top power rating of the SINAMICS G115D FSA wall-mounted frame, controlled entirely through hardwired I/O with Safe Torque Off on board (SIL 2 / PL d per the Siemens safety declaration). Bürklin carries it as NCNR stock — not suitable for new designs, which is exactly what a like-for-like repair order looks like.

Why is this FSA drive 60 mm taller than its catalog siblings?

The standard G115D FSA stands 156 mm high; this one measures 380 × 216 × 129 mm because the H0 interconnection builds a 24 V PSU into the housing. The payoff is at the wall: power and control wiring enter through cable glands, the local/remote switch (LRC) sits on the unit, and there is no separate 24 V power supply to mount, wire and fuse in the panel. In a distributed conveyor layout that saving repeats on every axis.

What does the drive still do without a fieldbus option?

Everything the zone needs locally: sensorless vector control across a 0–240 Hz output (0–550 Hz in V/f control), a 200% / 3 s (150% / 57 s) overload curve for conveyor breakaway torque, an integrated C2 RFI filter, and a 180 V DC brake output feeding the spring-applied brake directly. The alternative for new builds is a PROFINET or AS-Interface variant of the same frame — 2XD01-5AF0 or 2XD01-5AA0 in that band — but for an existing hardwired zone this AB0 unit drops in without a single network change.