The Siemens 3UG4501-2AA30 is a SIRIUS level monitoring relay with analog setting, designed to monitor liquid levels in tanks, sumps, or reservoirs. It switches a contact when the level crosses the setpoint, with an adjustable starting delay of 0.5 to 10 s to ignore splashes or turbulence. The 22.5 mm width fits standard DIN-rail panels alongside other SIRIUS control gear, and the IP20 housing is fine for enclosed cabinets — not for wet areas. Rated supply is 24 V AC/DC (50/60 Hz), with a dropout threshold of 0.85 × rated value. The output relay is rated 3 A at 250 V or 400 V (50/60 Hz), and 1 A at 24 V DC — enough to drive a small contactor coil or a PLC input directly.
Terminals accept 2 × (24 … 16) AWG solid or stranded — strip length is standard for the cage. The external reset input lets you wire a remote pushbutton to clear a latched fault without opening the panel. Clearance around the relay: 0 mm upwards, downwards, forwards, backwards, and at the side — so it can be packed tight against other devices without derating for airflow.