Omron Limit Switch

Omron Limit Switch, Industrial Use - D4N-1B20

This limit switch is a compact, industrial mechanical sensor designed to detect position changes and provide reliable switching for automation and control equipment. Engineered for environments where sealed performance matters, it offers multiple actuator styles and contact arrangements to suit safety and general-purpose roles. The product supports direct-opening mechanisms and can be installed with a variety of conduit or M12 connector options to simplify wiring and maintenance.

Features & Benefits

• IP67-rated sealing for protection against dust and temporary immersion
  Direct-opening NC contact for positive contact separation
  Mechanical durability of at least 15,000,000 operations
  Electrical durability up to 500,000 operations for 3A at 250 VAC
  Contact resistance maximum 25 mΩ for consistent signal integrity
  Operating temperature range −30°C to 70°C for wide ambient use

Applications

• Suitable for industrial conveyor end-of-travel detection
  Ideal for safety interlocks on access doors and guards
  Used with hoists and lifts requiring position feedback
  Can be used for machine-tool limit sensing in production lines
  Suitable for retrofitting older control panels as a replacement switch

What contact forms and switching patterns are available?

The internal modules include snap-action and slow-action types with 1 NC/1 NO, 2 NC, 2 NC/1 NO, 3 NC and make-before-break variants to match different control logic requirements.

How should it be wired to maintain the sealed rating?

Use recommended connectors or conduit adaptors with correct seal packing and tighten to the specified torque
for 1/2-14 NPT types, apply sealing tape to ensure IP67 performance.

What are the applicable electrical ratings for control circuits?

The switch meets AC and DC utilisation categories with rated currents such as 10A at 120 VAC and 3A at 240 VAC for typical switching loads
use a 10A gI or gG fuse for short-circuit protection to meet specified ratings.

How does the mechanism address contact sticking from metal deposition?

A direct-opening mechanism forces NC contacts apart via the plunger action so separation occurs even when metal transfer has occurred, preserving safety-oriented operation.

What environmental limits affect installation choice?

Avoid locations with explosive or corrosive gases, constant oil/water splashing or extreme condensation
the head is not impervious to fine particle ingress so protective placement is recommended.