The Allen-Bradley 440R-N23114 MSR126.1T, also cataloged as the MSR126.1T Safety Relay, operates as a dedicated hardware component for dual-channel input monitoring and safety output control within industrial logic platforms.

Model Suffix Analysis

The 440R-N23114 (MSR126.1T) designation indicates a specific hardware revision configured for dual-channel safety gate and emergency stop applications. The .1T suffix specifies the presence of fixed terminal blocks and internal circuitry calibrated for cross-fault detection across the input channels, distinguishing it from single-channel variants.

Technical Specifications

Allen-Bradley Industrial Control Architecture

This module integrates into PLC and control networks by providing deterministic safety state management. It adheres to strict I/O density scaling requirements within 22.5 mm enclosures, facilitating dense cabinet layouts. The internal logic is compatible with standard EtherNet/IP safety protocols where gateway interfaces permit. Firmware execution is hardware-locked to ensure deterministic timing of the normally open safety contacts during input fault detection.

Ordering Info

• 1 x 440R-N23114 MSR126.1T Safety Relay

• 1 x Product specification sheet

Field Installation Protocols

• Mounting: Install the device on a 35 mm DIN rail. Ensure vertical orientation to maintain convection airflow within the enclosure.

• Grounding: Terminate the safety circuit return to the system protective earth (PE) bus. Maintain separation between safety signal wiring and high-current power cables to prevent induced noise.

• Wiring: Utilize copper conductors rated for the operating temperature. Ensure that all terminal connections are secured to prevent vibration-induced loosening.

Frequently Asked Questions

• Does this relay support hot-swapping?

  No, the 440R-N23114 does not support hot-swapping. Disconnect all power sources before performing maintenance or module replacement to prevent electrical damage.

• What is the function of the S33-S34 jumper?

  The jumper across S33-S34 configures the relay for automatic reset mode. In this mode, the relay outputs engage immediately when safety inputs are closed, bypassing manual reset requirements.

• How does cross-fault detection operate?

  The relay monitors the relationship between the two input channels. If a short circuit occurs between the channels, the relay identifies the discrepancy and prevents output activation.

• Can the N.C. auxiliary outputs be used for safety functions?

  No, the N.C. auxiliary outputs are for monitoring purposes only and are not rated for safety-critical machine stop functions.

• What is the minimum switched current requirement?

  The relay requires a minimum current of 10 mA at 10 V to ensure reliable contact wetting and maintain signal integrity.

• Is the firmware user-upgradable?

  No, the device utilizes fixed internal logic. There is no provision for field firmware updates or user-side configuration of the safety logic parameters.

• What does the K1/K2 LED status indicate?

  The green LEDs indicate that the internal redundant safety contacts for channel 1 and channel 2 are closed and the circuit is energized.

• Is an external feedback loop required?

  When using a monitored manual reset, the external contactor feedback must be wired in series with the reset button to ensure the relay verifies contactor state before activation.