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Brand: Allen-Bradley
Allen-Bradley 440G-T27121 TLS-1 GD2 Guard Locking Switch
Description
A power-to-release guard locking switch with 24V AC/DC solenoid
The Allen-Bradley 440G-T27121 is a TLS-1 GD2 guard locking switch of the Guardmaster 440G family, with a power-to-release lock, a 24V AC/DC solenoid and an M20 conduit entry. It is supplied without an actuator, so the actuator is ordered separately to suit the door hinge and the approach direction.
A power-to-release lock keeps the guard locked when the solenoid is not energized. That is the usual choice where stopping time is long, for example mixers, presses and spinning equipment, because loss of power cannot open the door while the hazard is still present.
Technical specifications
| Parameter | Specification |
|---|---|
| Catalog number | 440G-T27121 |
| Type | TLS-1 GD2 guard locking switch, power to release |
| Solenoid voltage | 24V AC/DC (the series covers 24V AC/DC, 110V AC or 230V AC) |
| Solenoid contacts | 1 N.C. + 1 N.O. |
| Safety and auxiliary contacts | 2 N.C. + 1 N.C. direct opening safety, 1 N.O. + 1 N.O. auxiliary (TLS-1) |
| Contact type | Break before make |
| Actuator | Not included |
| Conduit entry | M20 |
| Utilization category | A300 / AC-15: 240V 3 A, 120V 6 A |
| Thermal current | 10 A |
| Minimum current | 5V DC, 5 mA |
| Actuator holding force, max | 2000 N (450 lb) |
| Actuation speed | Min 100 mm per minute; max 160 mm per second |
| Ingress protection | IP67 |
| Operating temperature | -20 to +60 C |
| Mechanical / electrical life | 1,000,000 operations each |
| Rear release unit life | 10,000 operations |
| Torque settings | 1.4 N-m fixing bolts; 1.2 N-m lid screws; 1.0 N-m terminal screws; 0.8 N-m terminal block screws |
What the catalog data says
The installation sheet lists the TLS-1 version with two N.C. and one more N.C. direct-opening contact for safety, and two N.O. auxiliary contacts. Actuators are sold separately, and the sheet shows examples such as 440G-A27011 and 440G-A27143, with the actuator speed limits above. Fit guard stops and guides, because the switch must not be used as a mechanical stop.
The document also warns that spare actuators can weaken a safety system, so their use and availability should be controlled. The sheet’s warning also states that the escape release is for access through guarding and is not an emergency-stop device.
Installation checks
Mount with M5 bolts at 1.4 N-m, set the lock point as shown in the sheet, and use copper conductors in polymeric conduit with a single conduit entrance for the field connections. Safety contacts and solenoid feedback can be monitored together in series, or independently where jumpers are removed.
Two dual-channel safety circuits are common, wired to a relay such as the MSR127 or a safety PLC input. A power-to-release switch must never be the only protection against a hazard that persists after power is lost, which a risk assessment should confirm.
Related Allen-Bradley products: Allen-Bradley 440C-CR30-22BBB CR30 Configurable Safety Relay, Allen-Bradley 440R-ENETR GSR EtherNet/IP Interface, Allen-Bradley 440R-N23124 MSR127T Safety Relay 230V AC and Allen-Bradley 440R-N23135 MSR127RP Safety Relay 24V AC/DC.
Ordering and documents
Order 440G-T27121 exactly as printed. The hosted document is the TLS1-GD2 / TLS3-GD2 installation instructions 440G-IN003, and the photo is the official Rockwell product photograph of this part. Other safety devices are listed in the Safety Switches & Guard Locking category.
Seven Star LLC is an independent supplier in Muscat and quotes on request. Please confirm the catalog number, ratings and the current product status against the latest Rockwell Automation documents before ordering.
Datasheets & Documents
- Installation instructions TLS1-GD2 and TLS3-GD2 Escape Release Installation Instructions (440G-IN003) Download
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About brand
Allen-Bradley is the brand of Rockwell Automation for industrial control: ControlLogix and CompactLogix controllers, I/O systems, PanelView operator terminals, PowerFlex drives, motor control and industrial network equipment. The company began in Milwaukee in 1903, when Lynde Bradley and Dr. Stanton Allen formed the Compression Rheostat Company to make the motor speed controller Bradley had invented in 1901. It took the name Allen-Bradley in 1909 and was bought by Rockwell International in 1985. Since 2001 its owner has been Rockwell Automation, which is still headquartered in Milwaukee, Wisconsin.
Allen-Bradley company profile
| Founded | 1903, Milwaukee, Wisconsin, USA, as the Compression Rheostat Company |
|---|---|
| Founders | Lynde Bradley (inventor of the compression rheostat, 1901) and Dr. Stanton Allen (investor); Harry Bradley joined in 1904 |
| Name | Allen-Bradley Company from 1909 |
| Ownership | Acquired by Rockwell International in 1985 for about USD 1.65 billion; a brand of Rockwell Automation (NYSE: ROK) since 2001 |
| Headquarters | Milwaukee, Wisconsin, USA |
| Product families | Logix programmable automation controllers (ControlLogix, CompactLogix), legacy SLC 500 and MicroLogix PLCs, Micro800 controllers, POINT, FLEX and Compact I/O, PanelView HMIs, PowerFlex AC drives, contactors, motor starters and soft starters, safety components, Stratix Ethernet switches |
Milestones
- 1901: Lynde Bradley invents the compression rheostat to control the speed of electric motors.
- 1903: The Compression Rheostat Company is formed in Milwaukee with an initial investment of USD 1,000.
- 1904: Harry Bradley joins; a crane controller is shown at the St. Louis World's Fair.
- 1909: The company is renamed Allen-Bradley.
- 1985: Rockwell International acquires Allen-Bradley.
- 2001: Rockwell Automation becomes the company's name; the Allen-Bradley brand marks 100 years in 2003.
Reading Allen-Bradley catalogue numbers
The first digits of an Allen-Bradley catalogue number identify the platform, which tells you what is compatible with what. 1756 is ControlLogix (chassis-based, used for large process and plant control), 1769 is CompactLogix 5370 with Compact I/O, 5069 is CompactLogix 5380 with Compact 5000 I/O, 1734 is POINT I/O, 1794 and 5094 are FLEX and FLEX 5000 distributed I/O, 1746 and 1747 belong to the older SLC 500 family, 1766 is MicroLogix 1400 and 2080 is Micro800. For drives, 25B is PowerFlex 525 and 22B is PowerFlex 40; in a code such as 25B-D010N114, "D" means 380–480 V, "010" is the output current rating, and N114 instead of N104 means the drive has an integrated EMC filter. Many plants in the region still run SLC 500 and older MicroLogix systems, which Rockwell has discontinued, so exact spares and migration to CompactLogix are both common requests.
Where Allen-Bradley products are used
In Oman and the GCC, Allen-Bradley controllers and drives run on oil and gas facilities, water treatment and pumping stations, cement, food and beverage and packaging plants, and on machines supplied by American OEMs. ControlLogix is often the platform for plant control systems, while PowerFlex drives are used on pumps, fans and conveyors.
Allen-Bradley products we list
| Family | Examples |
|---|---|
| ControlLogix | 1756-L85E, 1756-EN2T, 1756-EN2TR, 1756-IF16, 1756-IB32, 1756-PA75, 1756-A10 |
| CompactLogix and Micro controllers | 5069-L320ER, 5069-L340ERM, 1769-L33ER, 1769-L16ER, MicroLogix 1400, Micro820, SLC 500 (1746) |
| Distributed I/O | 1734-AENTR, 1734-IB8, 1734-IE2C, 1734-IB8S safety, 1794-AENTR, 5094-AENTR, 5069-IF8 |
| Operator terminals | PanelView Plus 7 10-inch, PanelView Plus 7 15-inch, PanelView 800, PanelView 5310 |
| Drives, motor control and networking | PowerFlex 525, PowerFlex 755, PowerFlex 4, 150-A180NBD SMC, Stratix 2000, 1783-NATR |
Ordering Allen-Bradley products: what we need
Send the full catalogue number and the series letter from the label (for example 1756-EN2T Series D), because firmware and compatibility can change between series. For drives, add the motor power, voltage and filter option. For a discontinued SLC 500 or MicroLogix part, tell us whether you need the exact spare or a migration proposal.
Facts checked against Rockwell Automation's published company history, October 2026.
Browse Allen-Bradley products by category: PLC & I/O Cards, AC Drives.
FAQ
Questions about the Allen-Bradley 440G-T27121 TLS-1 GD2 Guard Locking
Answers from our engineering team on installation, compatibility and integration.
01What is 440G-T27121?
A TLS-1 GD2 power-to-release guard locking switch with 24V AC/DC solenoid and M20 conduit entry.
02Is an actuator included?
No, the listing says no actuator.
03What is the holding force?
2000 N maximum per the installation sheet.
04What is the enclosure rating?
IP67.
05Is it an emergency stop?
No, the installation sheet states that the escape release is not an emergency-stop device.
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