440N-Z21SS2H | Allen-Bradley SensaGuard non-contact interlock switch, 18 mm sensing, 8-pin M12, solid-state

The 440N-Z21SS2H is a non-contact safety interlock switch from Allen-Bradley’s SensaGuard series. It uses solid-state technology and operates without physical contact between the switch and actuator, ensuring reduced wear and extended lifespan. The device features 2 normally closed (N.C.) safety outputs and 1 normally open (N.O.) auxiliary output, designed for personnel protection in machine guarding applications. It ensures safe access control for doors, gates, and guards. Its operation is based on coded magnetic sensing and conforms to high safety standards.

This switch offers 2 PNP safety outputs (normally closed logic) rated at 0.2 A max, and 1 PNP auxiliary output (normally open logic) also rated at 0.2 A. The safety outputs are used to interrupt power to hazardous machinery when the guard is open or removed. The auxiliary output can be used for signaling or status indication in an HMI or PLC. All outputs are solid-state for fast and bounce-free switching. They are internally short-circuit and overload protected.

The 440N-Z21SS2H has an assured sensing distance of 18 mm (0.71 in.), which provides flexibility in actuator alignment. This non-contact detection helps reduce mechanical stress and wear on components. The switch only activates when a properly coded actuator is within sensing range. This enhances tamper resistance and operational reliability. Proper mounting is essential to maintain this sensing distance consistently.

The switch connects using an 889D DC Micro (M12) cordset, typically with 8-pin configuration. These cables are available in various lengths and configurations (straight or right-angle). The plug ensures quick disconnection for maintenance and strong mechanical retention. Using the proper Allen-Bradley cordset ensures compatibility and environmental sealing. Cable selection should consider length, shielding, and mounting constraints.

Yes, the 440N-Z21SS2H is an active product in the Allen-Bradley safety portfolio as of 2025. It is part of the widely used SensaGuard series, which continues to be supported and distributed globally. The product meets modern safety and performance standards, making it suitable for both new installations and system upgrades. However, it's always good to confirm availability with your local distributor for large-scale orders. Compatible accessories and actuator options are also readily available.