The Siemens SIRIUS 3RH2122-2KJ80 is a coupling relay for switching auxiliary circuits, sized S00 (45 mm wide, 73 mm deep, 70 mm high). The built-in suppressor diode handles the DC coil's back-EMF, so you don't need an external flyback diode across the coil terminals.
This relay carries 10 A at both 24 V rated value and 230 V rated value — that's the resistive load curve (AC-1 equivalent) for auxiliary contacts. At 60 V it's 4.7 A, at 110 V it's 3 A, and at 400 V it drops to 3 A. The AC switching frequency is rated at 10 000 1/h, so it keeps up with rapid-cycle applications like conveyor interlocking or valve sequencing.
Panel integration — DIN rail and clearance
The S00 footprint (45 mm wide) fits standard 45 mm-wide DIN-rail slots — one module per position.
Pollution degree 3 (industrial environment). Relative humidity minimum 10%. RoHS compliance date: 10/01/2009 (substance prohibition date). The relay is rated for operation in typical control panel conditions — no special derating needed for most industrial atmospheres.