The Siemens 3RK1323-5CS41-1AA3 is a reversing starter — a single device that handles forward/reverse motor control in a compact, IP65-rated enclosure. It's rated for 9 A at AC-3 duty at 400 V, which means it can switch a 4 kW induction motor on a 400 V line under full load without welding the contacts.
Supply voltage is 24 V DC nominal, with a permissible range of 20.4 to 28.8 V. The control circuit draws from the AS-Interface bus cable via the cutting/clamping method, so no separate control wiring is needed — just tap into the flat cable. Two M12 digital inputs are parameterizable for start/stop or interlock signals. Dimensions are 130 mm wide, 250 mm high, and 91 mm deep. That's a fairly tall footprint for a reversing starter — plan for vertical clearance in the panel. The load-side outgoing feeder uses an ISO23570 socket, and the main energy infeed uses the same standard, so the cabling pattern is fixed: you'll need the matching connector set.
The reversing starter mounts via the AS-Interface flat cable system — no DIN rail required, though the housing itself is designed for screw-fixing to a backplate. The IP65 enclosure means it can be mounted directly on the machine frame, close to the motor, rather than in a central control cabinet. The two M12 inputs accept standard 3-wire proximity sensors or limit switches, and the front addressing socket lets you set the AS-i address without opening the housing.