IP65 direct starter with dual-fieldbus connectivity
The Siemens 3RK1304-5KS40-2AA3 is a SIMATIC motor starter combining a direct starter (CLASS 10 trip class) with a remote I/O slice in an IP65 enclosure — rated for washdown and dusty environments on packaging lines or conveyor sections where a central cabinet isn't practical. It supports both PROFINET and PROFIBUS DP protocols, so it can drop into an existing Siemens fieldbus architecture without a gateway. The 24 V DC supply range is 20.4–28.8 V, and the unit draws power for both the electronics and the motor contactor coil from the same rail.
4 digital inputs, 2-byte process data, M12 connectivity
The module provides 4 digital inputs via M12 sockets (sensor connection) and no digital outputs — the motor switching is handled internally by the direct starter. Process data is mapped as 2 bytes input and 2 bytes output, which keeps the fieldbus cycle lean. Rated breaking capacity at 400 V is 100 kA with a rated current of 2 A — sized for small motors (typically 0.37–0.75 kW range) where the short-circuit withstand at the motor branch matters for coordination with upstream MCCBs. Power dissipation is 3.888 W whether the bypass circuit is active or not, so the thermal load inside the IP65 enclosure is predictable — no derating guesswork for sealed enclosures.
Panel fit and environmental ratings
Dimensions are 150 mm deep × 110 mm wide × 230 mm high, with screw fixing and an ISO23570 socket for the main energy infeed. Mounting position can be vertical or horizontal, which helps when fitting into tight machine frames. Shock resistance is 15g for 11 ms and vibration resistance is 2g — sufficient for direct mounting on machine frames or conveyor sections without additional vibration dampers.