## Key Specifications
Manufacturer: Leuze electronic

Series: 3B Series

Part Number: ETR3B/4P-M12 (often referenced without the ‘3’, as ETR3B/4P-M12)

Sensing Principle: Photoelectric diffuse sensor with energetic reflection.

Sensing Range: Adjustable, typically up to 300 mm.

Outputs: Complementary PNP outputs. This means it provides both a Normally Open and a Normally Closed signal.

Light switching (Normally Open – NO): Output is ON when an object is detected.

Dark switching (Normally Closed – NC): Output is ON when no object is detected.

Power Supply: 10 – 30 V DC

Connection: M12 plug, 4-pin

Light Source: LED (Red)

Housing: M18 threaded cylindrical body

## Wiring & Pinout
For a standard 4-pin M12 connector on this type of sensor, the pinout is as follows:

Pin 1: (Brown) +V (Connect to 10 – 30 V DC)

Pin 2: (White) PNP Normally Closed (NC) Output

Pin 3: (Blue) GND (Connect to 0V)

Pin 4: (Black) PNP Normally Open (NO) Output

## Functionality
This sensor emits a focused beam of red light. When an object enters this beam, the light reflects off the object’s surface and returns to the sensor’s receiver. If the amount of returned light is sufficient, the sensor’s outputs will switch state.

The adjustable sensing distance allows you to fine-tune the detection range for your specific application. Having both NO and NC outputs provides flexibility in control logic without needing to change wiring or sensor types. It is commonly used in automation for tasks like presence detection on conveyor belts, part counting, and positioning.

DATA SHEET

LEUZE ELECTRONICRK 85/7-10UC sensor