The Siemens 3UG4621-2AA30 is a SIRIUS current monitoring relay with a digital LCD and a measurable current range of 0.003 to 0.6 A, set via a 0.003 to 0.5 A adjustment window. It runs on 24 V AC/DC (20.4–26.4 V at 50/60 Hz) and snaps onto a standard 35 mm DIN rail — no tools needed for mounting. The IP20 housing keeps it safe for dry control-cabinet environments, pollution degree 3.
The 0.003–0.5 A setting range covers small motor loads, pump dry-run protection, and conveyor belt monitoring. The 0.6 A measurable ceiling gives headroom for the upper end of the adjustment. The 24 V AC/DC control supply is standard for PLC-driven panels; the 20.4–26.4 V tolerance handles a sagging 24 V bus without dropping out. The relay output is rated 3 A at 250 V AC and 400 V AC (50/60 Hz), and 1 A at 24 V DC / 0.2 A at 125 V DC / 0.1 A at 250 V DC — so it can switch a contactor coil or a small PLC input directly, but for higher DC loads you'll want an interposing relay.