The Siemens 3RP1540-2AB31 is a SIRIUS timing relay with a 24 V DC coil and a single changeover relay output. The adjustable time range spans 0.05 to 600 s, set via a front-panel potentiometer or DIP switches depending on variant — this unit carries a 0.85 initial value multiplier and 1.1 full-scale factor, meaning the actual delay equals the dial setting times these coefficients. Recovery time between cycles is 150 ms, and the minimum ON period is 200 ms, so it won't retrigger on fast transients. The relay contact is rated 1 A at 24 V DC, 0.2 A at 125 V DC, and 0.1 A at 250 V AC/DC — these are the switching limits, not the continuous carry current. The thermal current (Ith) is 5 A, which governs the continuous current through the contact path when the relay is not switching. For a 24 V DC control circuit, the 1 A switching rating is the number to check against your load's inrush and breaking requirements. Mounts on 35 mm DIN rail via the integrated snap-on latch, with screw terminals accepting 2 x (24–16 AWG) solid or stranded wire. The 22.5 mm width fits standard enclosure rail spacing; any mounting position is allowed. Operating temperature range is -25 to +60 °C, storage -40 to +85 °C.
Screw terminals accept 2 x (24–16 AWG) solid or stranded conductors. The 22.5 mm width and 91 mm depth fit standard 35 mm DIN rail enclosures; no additional clearance is required in any direction (0 mm spacing upwards, downwards, forwards, backwards, and to the side). Basic insulation with pollution degree 3 suits industrial control panels where conductive dust or humidity is present.