Generic LJ4A3-1-Z/AX Inductive Proximity Sensor NPN NC, 1mm Detection Range, Shielded, 10-30VDC

An NPN Normally Closed (NC) output provides a closed circuit (current can flow) to the common wire when the sensor is idle (no target detected). When a metal target enters the detection zone, the switch opens, interrupting the current. This is often used for fail-safe circuits where an open wire indicates a fault. Conversely, an NPN Normally Open (NO) output is open at idle and closes upon detection.

A 'Shielded' or 'Z-type' inductive sensor has its sensing coil surrounded by a metal shield (usually ferrite). This design focuses the electromagnetic field primarily forward from the sensing face, allowing for flush mounting in metal without false triggering. It also provides better immunity to electromagnetic interference (EMI) from nearby motors or drives compared to unshielded models.

This 3-wire sensor requires a 10-30VDC power supply. Connect the brown wire to the positive DC supply (+V), the blue wire to the negative/common (0V). The black wire is the NPN switched output. Connect the black wire to your PLC's digital input. The PLC input must be configured as a sinking input (connected internally to +V) to complete the circuit when the sensor's NPN transistor turns on.

Yes, inductive sensors can detect all conductive metals, but the effective sensing distance is reduced for non-ferrous metals like aluminum, copper, or brass compared to steel. The nominal 1mm detection distance is typically specified for mild steel. For non-ferrous metals, you should derate the sensing distance, often by 30-50%, and perform practical testing to determine the reliable operating distance for your specific application.