Allen-Bradley 440R-N23126 Guardmaster MSR127T Safety Relay, 24V AC/DC, Auto/Manual Reset
Allen-Bradley 440R-N23126 is a Guardmaster single-function safety relay (type MSR127T) with selectable automatic or manual reset, three normally open safety outputs and one normally closed auxiliary output on a 24 V AC/DC control supply.
Overview
The 440R-N23126 accepts 1 N.C., 2 N.C. or light curtain input contacts, so the same relay covers interlocked doors, multi-door chains and presence sensing devices. Fixed screw terminals speed panel wiring, the 0 to 40 °C ambient range with 80% non-condensing humidity suits most industrial enclosures, and the unit operates up to 1000 m above sea level.
Key Features
- Single-function safety relay, type MSR127T (Guardmaster family)
- 24 V AC/DC rated supply voltage
- Automatic or manual reset — selectable per application
- 3 N.O. immediate safety outputs + 1 N.C. auxiliary output
- Input contact: 1 N.C., 2 N.C. or light curtain
- Fixed screw terminals for direct panel wiring
- 0 to 40 °C operating range; 80% RH non-condensing; 1000 m max altitude
Technical Specifications
| Attribute | Value |
|---|---|
| Manufacturer | Allen Bradley (Rockwell Automation) |
| Product Line | Guardmaster Safety Relays (440R) |
| Part Number / Catalog No. | 440R-N23126 |
| UPC | 611320826920 |
| Product Type | Single-Function Safety Relay (MSR127T) |
| Rated Supply Voltage | 24 V AC / 24 V DC |
| Reset Type | Automatic / Manual Reset |
| Safety Outputs | 3 N.O. |
| Auxiliary Outputs | 1 N.C. |
| Input Contact | 1 N.C., 2 N.C. or Light Curtain |
| Terminals | Fixed Screw Terminals |
| Operating Temperature | 0 to 40 °C (32 to 104 °F) |
| Relative Humidity | 80% maximum (non-condensing) |
| Maximum Operating Altitude | 1000 m above sea level |
| Mounting | 35 mm DIN Rail |
| Dimensions | 13 x 13 x 4 cm (5.1 x 5.1 x 1.6 in) |
| Weight | 0.56 lbs (0.26 kg) |
Applications
Use the 440R-N23126 wherever a single guarded zone needs flexible reset behavior — automatic restart for high-cycle conveyor access doors, or supervised manual restart for maintenance hatches and light-curtain pass-throughs on assembly and material handling equipment.
Why Buy from Us
This safety relay is available new in original factory packaging, fully tested and backed by a standard warranty of 1 year. We ship worldwide with careful protective packaging and fast dispatch. Quantity discounts and repair/exchange options are available on request.
Documents
| Resource | Title | Link |
|---|---|---|
| Publication | 440R-IN079 — MSR127T / MSR127TP / MSR127R / MSR127RP Safety Relays Installation Instructions (English) | 440r-in079_-en-p.pdf |
| Publication | 440R-TD001 — Guardmaster Safety Relays Technical Data (English) | 440r-td001_-en-p.pdf |
| Data Sheet | MSR127T Safety Relay Specification Sheet | MSR127T.PDF |















