Schmersal BNS333-01YU Coded Magnet Safety Interlock Switch

Schmersal BNS333-01YU-M20 is a coded-magnet magnetic safety interlock switch with an integrated safety-evaluation module, designed to guard movable machine doors. It combines a magnet-coded actuator with a magnetic safety sensor that provides a single normally closed safety contact and on-board monitoring to ensure correct operation. Actuation is designed for rear mounting (actuation from rear, designated "U"), enabling tamper-resistant installations in compact guard slots. The device operates from 24 VAC or DC and draws approximately 40 mA, and it is offered in the M20 housing variant under part number 101169807 as part of Schmersal's BNS333 family. For complete guard-lock functionality, it is typically paired with coded-magnet actuators such as the BPS 300 or BPS 303, forming a safety gate system in line with EN 60947-5-3 requirements for safety sensors and interlocks. Common applications include protecting access to movable machinery on production lines, presses, conveyors, and packaging equipment.