Schmersal SRB-E-301ST Industrial Safety Relay Module

SRB-E-301ST is a configurable, multi-function safety relay module from Schmersal that can operate as a 1- or 2-channel control unit with a Start button or Auto-start option, and it includes three safety contact outputs plus one auxiliary contact for signaling or interlock tasks. Powered from 24 V AC/DC (±20%), it drives a safe-contact network rated up to 6 A per contact at up to 230 V, with a compact housing measuring 22.5 × 98 × 115 mm and removable terminals for straightforward wiring. The module features a fast STOP 0 response with a drop-out delay under 10 ms, and it is designed for safety-certified applications, carrying ISO 13849-1 and IEC 61508 compliance with a Category 4, PL/SIL e/3 rating and PFH < 1.8 × 10^-10/h. An auxiliary contact provides 24 V at 1 A for signaling or monitoring tasks while the unit remains suitable for use in safety monitoring of sensors and actuators in machinery.