PNP vs NPN Proximity Sensors – Simple Wiring Guide

In industrial automation, proximity sensors are widely used to detect objects without physical contact. The two common types are:

1. PNP Sensor:

Provides a positive (+V) output signal when an object is detected.
Wiring:
• Brown: +V (Power Supply)
• Blue: 0V (Ground)
• Black: Signal (sends +V)

2. NPN Sensor:

Provides a negative (-V) output signal when an object is detected.
Wiring:
• Brown: +V
• Blue: 0V
• Black: Signal (sends -V)

The diagram also shows how to connect sensors to a control system (PLC), HMI, relay card, and contactor.

Understanding the difference helps avoid wiring mistakes in real-world applications.