LJ12A3-4-Z/DX Inductive Proximity Sensor NC, 6–36VDC, 4mm Detection Range

This LJ12A3-4-Z/DX model features a Normally-Closed (NC) output. In its resting state (no target present), the output circuit is closed, allowing current to flow. When a metal target enters the 4mm sensing range, the output circuit opens, interrupting the current. This is the inverse logic of a Normally-Open (NO) sensor and is often used for fail-safe detection circuits.

As an inductive sensor, the LJ12A3-4-Z/DX is primarily designed to detect ferrous metals (like iron and steel) which provide the strongest signal. It can also detect non-ferrous metals (like aluminum, copper, brass), but the effective sensing distance may be reduced. The 4mm nominal range is typically specified for standard mild steel.

Connect the brown wire to your positive DC supply voltage (between 6V and 36V) and the blue wire to DC negative (ground). The black wire is the switched NC output signal. Connect it to your PLC input, relay coil, or indicator load, completing the circuit to ground. Ensure the total load on the black wire does not exceed the 300mA maximum current rating.

With its IP65 rating, the sensor is protected against dust ingress and low-pressure water jets from any direction. This makes it suitable for damp industrial environments or occasional washdowns. However, it is not submersible or rated for continuous high-pressure water exposure or outdoor flooding.