Direct starter, MCU-controlled, IP55 — fits a washdown-adjacent panel
The Siemens SIRIUS 3RK4353-3DR58-0BA0 is a direct motor starter with MCU-based control logic integrated on site — no separate PLC or fieldbus slice needed for the motor branch. It's rated AC-3 at 1.25 A on 400 V, which means it's sized for small three-phase induction motors up to roughly 0.5 kW under standard starting duty. No PROFINET or PROFIBUS onboard, so the control signal comes from a hardwired digital input; the single digital input handles the start/stop command.
Supply and ambient — what the ratings actually govern
The operating voltage range is 340 to 440 V AC, and the control supply is AC as well — 184 to 253 V at 50 Hz, 196 to 253 V at 60 Hz. That means it runs off a standard 230 V control transformer, not a 24 VDC bus. If your panel is all 24 VDC auxiliaries, this unit won't drop in without a separate AC supply. Ambient temperature is rated -25 to +35 °C during operation; above that, you'll need to derate or ventilate the enclosure. The bimetal motor protection element handles the thermal curve, and short-circuit backup is via circuit-breakers, not fuses — that's a panel-builder detail that affects the coordination study.