Allen Bradley 440R-N23114 Guardmaster MSR126.1T Safety Relay

Allen-Bradley 440R-N23114 Guardmaster MSR126.1T Safety Relay

The Allen-Bradley 440R-N23114 Guardmaster MSR126.1T Safety Relay is a compact safety monitoring relay designed for dual-channel safety circuits. It is used to monitor safety devices such as emergency stop pushbuttons, safety gate switches, and interlock circuits, providing monitored safety outputs and auxiliary contacts for machine safety control systems. The relay supports both automatic and manual reset modes and is housed in a narrow 22.5 mm DIN rail-mounted enclosure.

Product Specifications

Safety Monitoring Function

The MSR126.1T is designed to monitor dual-channel safety devices and evaluate the consistency of both input channels before enabling the safety outputs. This architecture helps detect faults such as contact welding, wiring failures, or channel discrepancies within the safety loop.

When a monitored safety device is actuated, the relay de-energizes its safety outputs to remove power from the controlled machine circuit. Operation can be restored through a configured reset sequence once the safety condition has been cleared.

Inputs and Outputs

The relay accepts two normally closed safety input channels, making it suitable for dual-channel emergency stop circuits and guard interlock switches. This configuration supports fault detection and helps maintain the integrity of the safety function.

Two immediate safety outputs are provided through normally open contacts intended for safety-related machine shutdown circuits. In addition, two auxiliary normally open contacts are available for status indication, control system signaling, or non-safety functions.

Reset Configuration

The MSR126.1T supports both automatic and manual reset operation. Manual reset is commonly used where operator acknowledgment is required before machine restart, while automatic reset may be suitable for applications where risk assessment permits automatic restoration after the safety device returns to a safe state.

The reset mode should be selected according to machine safety requirements and the applicable safety standard.

Installation Characteristics

The relay is housed in a 22.5 mm wide enclosure designed for mounting on a standard 35 mm DIN rail. Fixed screw terminals provide secure field wiring connections for safety inputs, reset circuits, and output contacts.

The IP40 enclosure rating and IP20 terminal protection make the unit suitable for installation inside a properly rated control panel.

Frequently Asked Questions

Q: What safety devices can be connected to the 440R-N23114?

A: The relay is designed for dual-channel safety devices such as emergency stop pushbuttons, safety gate switches, and mechanical safety interlock contacts using two normally closed input channels.

Q: Does the relay support manual reset operation?

A: Yes. The MSR126.1T supports both automatic and manual reset modes, allowing the reset strategy to be selected according to the machine safety design.

Q: How many safety outputs are available?

A: The relay provides two immediate normally open safety outputs and two additional normally open auxiliary outputs.