Allen-Bradley 440R-M23145 Guardmaster Safety Relay

The Allen-Bradley 440R-M23145 Guardmaster MSR138DP is a 115V AC, single-function safety relay designed to monitor safety inputs and generate controlled safety outputs for Guardmaster safety circuits in industrial automation. Powered from 115 VAC, it accepts safety signals from devices such as light curtains and door interlocks, supports 1NC/2NC input configurations, and provides two normally open safety outputs to the control logic. The unit includes a delayed-output option with a 0.5 to 10-second time delay, enabling safe sequencing and controlled restart, and it can operate in Automatic or Manual (monitored manual) modes, with removable terminal blocks for easy wiring. With a 45 mm-wide housing designed to fit standard control panels, the MSR138DP is a compact component in the Guardmaster line that helps ensure machine safety by requiring proper sensor conditions before a restart.