Generic LJ5A3-1-Z/AX Inductive Proximity Sensor NPN NC, 1mm Detection, 10-30VDC, IP65

An NPN Normally Closed (NC) output provides a continuous current path to ground (sinking) when no target is present. When a metal object enters the sensing range, this path opens, interrupting the signal. Conversely, an NPN Normally Open (NO) output only provides a path to ground when a target is detected. The NC configuration is often used for safety-critical circuits where a wire break should trigger a fault state.

Yes, inductive proximity sensors can detect all conductive metals, but the effective sensing distance (Sn) is reduced for non-ferrous metals. For this LJ5A3 model with a 1mm nominal range for steel, the sensing distance for aluminum or copper will be approximately 0.3-0.5mm. Always verify detection reliability with the actual target material during system commissioning.

Connect the sensor's brown wire to the positive DC supply (10-30VDC), and the blue wire to the supply common (0V). Connect the black (signal) wire to your PLC's digital input terminal. The PLC input's common must be connected to the positive supply voltage (sourcing input). With no target present, the NPN NC switch is closed, completing the circuit and the PLC input reads 'ON'. When a target is detected, the switch opens and the input reads 'OFF'.

A 'shielded' or 'flush-mountable' inductive sensor has its sensing face surrounded by a metal ring (the shield). This allows the sensor to be installed flush with, or embedded into, a metal mounting bracket without the surrounding metal causing false triggers. Unshielded sensors require a clearance zone around the sensing face. The LJ5A3-1-Z/AX is a shielded design, offering greater installation flexibility.