Pro-Range CLJ-C18-5ANB NC NPN Inductive Proximity Sensor - 5mm Detection, 18x18mm Thread

This is a 3-wire DC sensor. Connect the brown wire to your positive DC supply (typically 12-24V), the blue wire to the DC common (0V), and the black wire is the NPN Normally-Closed output signal. The black wire will switch to a low voltage (near 0V) when a metal target is detected, sinking current to the common (blue) line. Always connect a pull-up resistor to the black wire if interfacing with a microcontroller input.

Inductive sensors are primarily optimized for ferrous metals (steel, iron). While they can detect non-ferrous metals like aluminum or copper, the effective sensing distance will be significantly reduced, often by 30-50% or more. For reliable detection of non-ferrous metals, it is recommended to test with the actual target material or select a sensor specifically rated for such applications.

A Normally-Closed (NC) output provides a continuous signal path (logical '1' or voltage high) when no target is present. When a metal target enters the detection zone, the switch opens, breaking the circuit (logical '0' or voltage low). A Normally-Open (NO) output behaves oppositely. The NC configuration is often used in safety-critical circuits, as a broken wire or loss of power mimics a 'target detected' state, triggering a fault condition.

For accurate and stable operation, maintain a clearance of at least one sensor diameter (18mm) from any surrounding metal objects (like the mounting bracket or machine frame). This prevents the sensor's electromagnetic field from being influenced by adjacent metal, which can cause false triggering or a reduction in the nominal sensing distance. Use non-metallic spacers if necessary.