The Siemens 3RK1300-0ES01-1AA0 is an EM 300 RS electromechanical reversing starter designed for the ET 200X distributed I/O family. It integrates motor reversing, overload protection via a bimetal relay, and PROFIBUS DP communication into one IP65-rated enclosure — so it mounts directly on the machine, not in a central panel. The setting range of 0.28 to 0.4 A covers small motors up to 0.1 kW at 400 V AC-3 duty, which means it handles light reversing loads like conveyor drives or valve actuators where space is tight and washdown is a concern.
The 0.28–0.4 A setting range is the bimetal overload relay's adjustment window — set it to match the motor's full-load current. At 400 V AC-3 (switching squirrel-cage motors), the rated power is 0.1 kW; that is a small motor, typical of a dosing pump or a small fan. The operating voltage of 400 to 500 V means it works on three-phase 400 V or 480 V systems common in industrial plants. That is modest — it is sized for the motor branch, not the main feeder. The ambient temperature range of 0 to 55 °C covers unheated plant floors but not hot process areas.
This reversing starter connects to the ET 200X backplane via a 9-pole motor feeder and a 9-pole power connection, both using tab terminals. It communicates over PROFIBUS DP, so the PLC sees the starter's status and can command forward/reverse without separate control wires. The form factor — 140 mm wide, 270 mm tall, 134 mm deep — fits in a standard IP65 enclosure sized for the ET 200X family. There is no motor brake output on this version, so if the load needs a holding brake, you add an external contactor.