Generic LJ18A3-8-Z/AY Inductive Proximity Sensor PNP NC, DC 6–36V, 6.4mm Detection Range

This LJ18A3 model has a PNP (sourcing) output. In its Normally-Closed (NC) configuration, the output signal wire switches to the positive supply voltage when no target is present. When a metal target enters the sensing range, the output switches to a low state (connected to 0V). This is the opposite logic of an NPN (sinking) sensor and is typically used to interface directly with PLC digital inputs configured for PNP sourcing signals.

No, standard inductive proximity sensors like the LJ18A3 series are primarily designed to detect ferrous metals (iron and steel). The sensing distance is reduced significantly or may not function at all for non-ferrous metals like aluminum, brass, or copper. For non-ferrous detection, a capacitive proximity sensor would be required.

In common inductive sensor nomenclature, suffixes like 'Z/AY' often denote specific electrical and mechanical variants. Here, 'Z' typically indicates a 2-meter cable length (though this unit has 1.2m), and 'AY' often specifies a PNP Normally-Closed (NC) output configuration. Always verify the exact specifications against the datasheet for critical integration.

Yes, the LJ18A3-8-Z/AY is a shielded (flush-mountable) type. This design contains the magnetic field, allowing sensors to be mounted adjacent to each other or flush in metal without a reduction in the nominal sensing distance or causing mutual interference, which is essential for multi-sensor applications.

Connect the brown wire to your DC positive supply (6-36V), the blue wire to DC negative (0V/common). The black wire is the PNP switched output. For a Normally-Closed (NC) sensor, the black wire will be at supply voltage when idle (no target). Connect the black wire to your PLC's digital input. The PLC input's common must be connected to 0V to complete the circuit when the sensor switches.