Schmersal SRB-E-301MC Safety Relay With Monitoring Contacts

Schmersal SRB-E-301MC is a multifunction safety relay module designed for safe evaluation of signals from position switches and safety sensors in control cabinets, supporting two-channel safety circuits with start/feedback circuit monitoring, with variants including SRB-E-301MC-CC and SRB-E-301MC20. It features three safety contacts and a signal contact (41/42) with normally-closed parallel contacts, enabling both safety switching and a diagnostic signaling function. The module operates from a 24 V AC/DC supply and uses plug-in screw terminals with coding; conductors of 0.2–2.5 mm² are supported (including fine wire with ferrule 0.25–2.5 mm²). Cable lengths support long runs—up to 1,500 m with 1.5 mm² and 2,500 m with 2.5 mm²—and it is designed for installation in control cabinets to monitor safety devices such as E-stops, guard doors, safety solenoids, and AOPDs.