The Siemens 3RT2316-2AP00 is a SIRIUS size S00 contactor rated for 9 A at 400 V in AC-3 duty, which means it handles motor switching up to 4 kW — a common size for small conveyors, pumps, and fans in a control panel. The coil is AC-operated at 230 V, 50/60 Hz, drawing 0.25 A holding current, so factor that into your control transformer sizing — it's a standard 230 VAC coil, not a 24 VDC one you'd find on a PLC-driven cabinet. Spring-loaded terminals on both the main circuit and the magnet coil mean no screwdriver needed for termination — strip and push, which shaves time on a multi-contactor panel build.
The 45 mm width (three 15 mm module spaces) fits a standard DIN rail slot. Side-by-side mounting is allowed, but you need 6 mm clearance to the side of adjacent devices for heat dissipation. Vertical mounting surface allows +/-180° rotation; you can also tilt it forward/backward by +/-22.5°. Upwards, forwards, and downwards clearance all need 10 mm, so plan your ducting and wire bends accordingly.
Main circuit terminals accept solid conductors 2x (0.5 to 2.5 mm²) or stranded 0.5 to 4 mm². Auxiliary contacts also accept 2x (0.5 to 2.5 mm²) solid or stranded up to 4 mm². That's enough for a 4 kW motor feed with standard 2.5 mm² power cable plus a control loop in the same terminal. Two auxiliary contacts are attachable, and the contactor comes with an auxiliary switch built in, so you can wire a feedback signal to the PLC without an add-on block for basic status.
Relative humidity minimum 10% — fine for most indoor panel environments, but if your panel sits in a washdown area or unheated warehouse, the storage range covers the extremes. Rated impulse withstand voltage is 6 kV for the main circuit, and the contactor carries a typical mechanical endurance of 30 million operations — that's a lot of cycles for a machine running at one cycle per minute.