Safety Local Isolator Module — What It Is and Where It Fits
The Siemens 3RK1304-0HS00-7AA0 is a SIMATIC safety local isolator module, designed to sit between the motor starter and the control network in a distributed safety architecture. It provides a local isolation point that opens the load circuit in a safe state, meaning when the safety function is triggered, the power path to the motor is physically broken — not just a logic-level signal. This is a key distinction from a standard contactor: the isolator module guarantees galvanic separation at the load terminals. Rated for 16 A at 400 V AC with a short-circuit withstand of 50 kA at 400 V, it handles motor branch circuits in industrial control panels where high fault currents are possible. The IP65 enclosure means the module can be mounted directly on the machine frame or in a field junction box without a separate cabinet — suitable for washdown zones or dusty environments. Communication is dual-protocol: PROFINET and PROFIBUS DP are both supported, so it drops into either a PN or PB line without a gateway. The module presents 1 byte of input data and 0 bytes of output data — it reports status but does not consume cyclic output data from the controller.
Power Supply and I/O — What Connects Where
Supply voltage is 24 V DC nominal, with a permissible range of 20.4 to 28.8 V DC. The module draws its control power from this 24 V bus; the motor power path is the separate 400 V AC circuit through the main energy infeed socket (ISO23570). Two digital inputs are provided for external safety signals (e.g., E-stop, guard door switches). All four input signal connections use M12 sockets — standard 4-pin or 5-pin M12 connectors, depending on the sensor wiring. There are no digital outputs on this module; it is a pure input-and-isolation device. Mounting is by screw fixing in any orientation. The dimensions are 230 mm high, 110 mm wide, and 170 mm deep — a compact footprint for a safety isolator with integrated dual-protocol networking. Pollution degree 3 rating means it is suitable for industrial atmospheres with conductive dust or occasional condensation.
Environmental and Mechanical — What the Ratings Mean for the Line
Operating temperature range is -25 to +55 °C, which covers most factory-floor conditions without derating. Storage and transport range extends to -40 to +70 °C, so the module can sit in an unheated warehouse or truck without damage. Vibration resistance is 2 g; shock resistance is 15 g for 11 ms. These figures mean the module can be mounted on a machine frame or conveyor section that experiences moderate vibration and occasional impact — it is not a fragile panel-only component. MTTFd is listed at 100 a. The safe state is load circuit open.