The ABB 2TLA050021R1200 is a compact tongue interlock safety switch from the MKEY1 series, configured with 2NC/1NO contacts and a flat key actuator. It sits in the safety relays subcategory, used to guard access to hazardous machine zones by interrupting the safety circuit when the guard is opened. The 2NC contacts provide a redundant break path for the safety loop (typically wired to a safety relay or safety PLC input), while the 1NO auxiliary contact signals guard status to the controller. The flat key profile suits standard guard-door alignment.
Rated for use in safety circuits up to SIL 3 / PL e when wired per the manufacturer's application diagram (the redundant NC contacts in series with the safety monitoring device). The compact housing fits standard 40 mm cutouts and accepts a flat key actuator with a 3 mm offset tolerance.