The SINAMICS G115D 6SL3520-0XE44-0AF0 is the 4 kW wall-mounted distributed frequency converter in FSB frame with AS-Interface communication — the transition point in the SINAMICS G115D series where FSB requires integrated fan cooling to sustain continuous operation at this power level. Designed for mid-power conveyor zones in brownfield AS-i plants, it delivers 10.2 A rated output current with 200% overload for 3 seconds, driving IE3 asynchronous or IE4 synchronous reluctance motors via direct SIMOGEAR 2KJ8 geared motor mounting. AS-Interface provides 4-bit cyclic I/O for speed setpoints and status feedback over the two-wire yellow cable, with STO via F-DI — a drop-in drive upgrade for existing AS-i conveyor sections that need 4 kW capability without pulling new network cables.

Why choose AS-Interface for a 4 kW FSB drive?

For plants with an established AS-i infrastructure, the AF0 variant connects to any standard AS-Interface master over the two-wire yellow AS-i cable — no Ethernet switches, no IP addressing, no additional network topology. Five drives on the same conveyor line share the same AS-i cable, daisy-chained from node to node. Each drive appears as a standard AS-i slave with 4-bit cyclic data exchange. Acyclic parameter access via AS-i 3.0 masters enables drive configuration over the same two wires. For brownfield conveyor retrofits where the AS-i backbone already serves sensors and actuators, adding a G115D AF0 drive is a two-wire connection.

What distinguishes the 4 kW FSB fan-cooled platform?

The 4 kW FSB (425 × 180 × 169 mm, 7.52 kg) is the first FSB power rating that requires integrated fan cooling — below this, FSB fanless (2.2–3 kW) relies on natural convection. The integrated fan adds 35 mm to the enclosure depth vs. fanless FSB (134 mm → 169 mm) and increases 24 V DC consumption to approximately 510–550 mA (vs. 250–290 mA fanless). This is the key design tradeoff at 4 kW: active cooling enables continuous operation at higher power density in the same FSB footprint, at the cost of marginally higher DC power consumption and fan-related maintenance considerations.

How does STO work on this drive?

Unlike the PROFINET AB0 variant which tunnels STO over PROFIsafe, the AF0 variant achieves Safe Torque Off via the fail-safe digital input (F-DI) — a dedicated 24 V DC safety signal from an external safety relay or emergency stop circuit. The approach is SIL 2 / PL d compliant and proven in thousands of AS-i conveyor installations.

Frequently Asked Questions

Can I upgrade this drive to PROFINET later?

No — the communication interface is determined by the hardware variant at order time. To migrate to PROFINET, replace the drive with the AB0 variant (e.g., 6SL3520-0XE44-0AB0). The motor, gearbox, mounting, and power connections remain unchanged.

What is the difference between XE44 and XH24 for the same 4 kW rating?

XE44 and XH24 are catalog designations for the same 4 kW FSB fan-cooled hardware platform — mechanically and electrically identical (425 × 180 × 169 mm, 10.2 A rated, integrated fan). Both support AB0 (PROFINET) and AF0 (AS-Interface) variants. The drives are functionally interchangeable; the distinction is commercial catalog organization.