A-B 800FM-LMT64 Limit Switch

The Allen-Bradley 800FM-LMT64 is not a traditional limit switch, but an 800F series 22 mm illuminated mushroom push button / emergency stop operator (twist-to-release type).

It is commonly used in industrial control panels and machine safety circuits.

Product Information

• Brand: Allen-Bradley (Rockwell Automation)
• Series: 800F / 800FM
• Part Number: 800FM-LMT64
• Type: Illuminated Emergency Stop / Mushroom Push Button
• Operation: Twist-to-release (latching safety button)
• Mounting size: 22.5 mm panel cutout

Key Characteristics

• Function: Emergency stop / safety shutdown input device
• Head type: 60 mm red mushroom head
• Operation: Latching (stays pressed until manually released)
• Illumination: Yes (integrated light option depending wiring)
• Protection: IP66 / industrial-rated enclosure design
• Contact block: Modular (NO/NC blocks attached separately)

Function (Simple Explanation)

This device is used to:

• Immediately stop a machine when pressed
• Stay in locked state after activation
• Require twist reset to restart system
• Provide visual safety status (lit/unlit depending version)

It is part of a safety control circuit, not a sensing limit switch.

System Role

It connects to:

• Safety relay modules
• Safety PLC inputs
• Contactor control circuits

It does not detect position like a limit switch, instead it is a manual safety command device.

Typical Applications

• CNC machine emergency stop
• Production line safety panels
• Conveyor emergency shutdown
• Robotics safety stations
• Industrial machinery control cabinets

Key Features

• Large mushroom head for fast emergency access
• Twist-to-release safety mechanism
• Modular contact block design
• High durability industrial construction
• Clear visual safety indication (illuminated versions)

Precautions

• Must be wired into safety-rated circuits only
• Do not bypass NC safety contacts
• Correct 22 mm panel cutout required
• Contact blocks must match correct configuration
• Illumination requires correct 24V wiring (if applicable)