The Siemens 6SL3520-0XE04-0AF0 is the 4 kW AS-Interface variant in the SINAMICS G115D distributed drive family, carrying the XE04 catalog designation — the entry point of the XE0x sub-series at 4 kW. XE04 identifies the same FSB fan-cooled hardware as XE44 in the XE4x sub-series but under a different commercial catalog code. The 4 kW FSB occupies a critical engineering threshold: it is the lowest-power G115D variant that requires integrated fan cooling, because natural convection — sufficient for the 0.37–3 kW fanless frames — cannot reject the heat generated at 10.2 A continuous output.

Why does 4 kW require fan cooling when 3 kW does not?

The G115D fanless ceiling is 3 kW (FSB frame, 425×180×134 mm, 7.12 kg, natural convection). At 4 kW, the output power loss exceeds what the die-cast housing can passively dissipate — even with the larger FSB surface area. Siemens adds a 35 mm-deep integrated fan module (increasing depth from 134 to 169 mm, weight from 7.12 to 7.52 kg) that forces airflow through internal heatsink fins. The fan is rated for continuous operation at 40°C ambient and is the sole rotating part in an otherwise solid-state assembly. Engineers designing 4 kW+ conveyor zones must account for this depth increase in the drive mounting envelope — the fan module adds 35 mm behind the drive that must clear machine structures and cable ways.

The AF0 AS-Interface variant uses the two-wire yellow flat cable for speed commands and diagnostic feedback. STO (Safe Torque Off) is achieved via the fail-safe digital input (F-DI), not PROFIsafe — the AF0 communication module does not carry safety protocols. For conveyor systems standardized on AS-Interface, this is the 4 kW drive to specify: the wiring infrastructure that serves the lower-power AS-i drives on the line also connects the 4 kW units with no additional cabling or switch hardware.