Safety Relays

This category stocks Allen-Bradley Bulletin 440R Guardmaster safety relays, covering a broad range of MSR-series modules designed to monitor emergency stop circuits, safety gates, light curtains, and speed-sensing applications. Families represented include the MSR127, MSR131, MSR132, MSR138, MSR142, and MSR57 series, with units available in both 24V AC/DC and 230V AC input versions and housing widths commonly at 22.5mm. Reset modes span automatic, manual monitored, and remote configurations, and the selection includes both fixed and removable terminal variants. The MSR57 speed monitoring relay addresses safe-speed and standstill detection requirements. Controls engineers sourcing Guardmaster safety relay replacements or building new safety circuits to SIL or PLe standards will find a working inventory of catalog numbers across the 440R bulletin here.