Guardmaster 440R

The Allen-Bradley Guardmaster 440R is a family of safety relays designed to monitor safety-rated inputs — such as E-stops, safety gates, light curtains, and two-hand controls — and provide forced-guided output contacts for machine safety circuits. With over 100 catalog numbers, the family spans multiple MSR model series, each encoded in the bulletin suffix: the letter immediately following 440R- identifies the series (B = MSR5T, C = MSR131RTP, D = MSR125H/HP, E = MSR132E/ED, G = MSR142RTP, M = MSR138DP, N = MSR126/127, S = CU4/MSR57), while the numeric portion encodes supply voltage, reset mode (automatic/manual or monitored manual), and terminal style (fixed vs. removable). For example, 440R-D23166 is the MSR125H at 24V DC with fixed terminals, 440R-M23148 is the MSR138DP at 230V AC with removable terminals, and 440R-G23216 is the MSR142RTP at 24V AC/DC with automatic/manual monitored reset. Supply options across the family include 24V AC/DC, 24V DC, and 230V AC. Full catalog-number construction details are available in the Guardmaster 440R Safety Relay Technical Data (440R-TD001).