LJ12A3-4-Z/BY PNP DC 6-36V 4mm Tube Type Inductive Proximity Sensor Switch
Inductive Proximity Sensor (LJ12A3-4-Z/BY)
Overview
Industrial non-contact metal detection sensor
Type: Inductive Proximity Sensor (PNP, Normally Open)
Detects metal objects only
Cylindrical M12 tube-type design
Used in automation, CNC, robotics, 3D printers
Working Principle
Sensor generates an electromagnetic field
When metal comes near eddy currents are induced
This disturbs the magnetic field
Sensor detects change switches output ON/OFF
Works without physical contact (no wear & tear)
Key Specifications
Oong>Output Type: PNP, Normally Open (NO)
Detection Distance: 4 mm
Output Current: Up to 300 mA
Sensor Diameter: 12 mm (M12 thread)
Response Frequency: ~0.5 kHz
Operating Temperature: -25C to +70C
Cable Length: ~11.2 m
Protection: Reverse polarity & short-circuit protection
Wire Configuration (3-Wire PNP)
Brown VCC (+636V)
Blue GND
Black Output (signal)
Output becomes HIGH when metal is detected
Fast switching response
Resistant to dust, oil, vibration
Built-in LED indicator
Suitable for harsh industrial environments
Applications
CNC machines & automation
3D printer auto bed leveling
Conveyor belt object detection
Position sensing in robotics
Limit switch replacement
Metal detection systems
Usage Tips
Detects only metal (not plastic/wood)
Maintain distance 4mm for detection
Use proper voltage (6V required)
For microcontrollers use voltage divider or relay
Ensure correct
No physical contact long lifespan
High durability in industrial use
Fast and reliable switching
Easy installation (threaded mount)
Limitations
Cannot detect non-metal objects
Fixed detection distance (not adjustable)
Requires higher voltage than Arduino (needs interface circuit)
Summary
Inductive proximity sensor (PNP NO)
Detects metal objects within 4mm range
Operates on 636V DC
Ideal for industrial automation & robotics