Schmersal BNS33-02Z-2187-3M Door Interlock Safety Switch

Schmersal BNS33-02Z-2187-3M is a magnetic safety interlock switch from the BNS 33 family, designed for securing movable machine guards and access doors in automation cells. It uses two normally closed contacts (DPST‑NC) and provides a 3 m potted lead cable, making integration straightforward into guard circuits. The device is rated for up to 100 V (AC/DC) and 250 mA, and it offers an IP67 enclosure rating for robust operation in dirty or damp environments. With a sensing range of approximately 5–15 mm, it coordinates with standard door actuators and guard interfaces to enforce safety conditions before machine restart. The 2187 variant indicates contacts are individually lead-out, and the 3M suffix confirms the 3-meter cable length included with the part. Typical applications include safety interlock duties on movable guards for presses, CNC machines, and robot-integrated work cells, where guarding a hazardous access point is essential. This Schmersal part is commonly paired with compatible safety controllers to monitor lock status and ensure proper lock release sequencing in automated production lines.