Siemens SIRIUS 3SE4 Safety Position Switch

The Siemens SIRIUS 3SE4 is a safety position switch (interlock switch) for monitoring guard doors, access hatches, and movable protective guards on industrial machinery, providing the positive-opening contact action required by IEC 60947-5-1 Annex K to ensure the contact opens mechanically rather than relying on spring return — the critical safety property that prevents a welded contact from leaving a machine unsafely de-energised after a guard door closing event. The 3SE4 tongue actuator design operates when the tongue (fixed to the guard door) enters or exits the switch head, making and breaking the safety circuit contacts with a definite snap action independent of door closing speed.

The 3SE4 safety contact block provides 2NC + 1NO contact configuration in the standard version, with the NC contacts connected in the safety circuit and the NO contact providing machine status feedback to the PLC. IEC EN ISO 14119 interlock switch standard compliance is certified, covering the risk of defeat of the interlocking device — requiring a coded actuator variant of the 3SE4 where higher tamper resistance is required (Category 2 or 3 actuator coding). The IP67 sealed head and M20 conduit entry handle the dust, oil, and coolant splash environments of metalworking and food processing machinery. A solenoid locking variant prevents the guard door from being opened while the machine is in motion, adding guard locking (interlock with guard lock) to the interlock function for high-inertia machine applications.

In Saudi Arabia, the SIRIUS 3SE4 KSA is the standard guard door safety switch for machinery compliance with SASO 2728 / IEC 60204-1 and the machinery CE marking requirements of Saudi Arabia's industrial equipment import regulations. Panel builders and system integrators assembling machine safety circuits at Saudi industrial facilities routinely specify the 3SE4 for its compliance track record, wide range of mounting options (horizontal and vertical head mounting), and compatibility with the SIRIUS 3SK1 and 3SK2 safety relay/controller range. The solenoid locking variant is increasingly specified at Saudi Aramco and SABIC facilities for robot cell guard doors where machine coastdown time exceeds the guard door opening time.

Razz Middle East supplies 3SE4 safety switches in standard and solenoid locking variants with a range of actuator coding levels and head mounting configurations.