The five choices that specify an inductive sensor — barrel size, rated sensing distance Sn, flush or non-flush mounting, output transistor type (PNP/NPN) and switching function (NO/NC) — with the correction factors for target material and the catalogue's OsiSense XS size ladder.
An inductive sensor drives a coil in its face with a high-frequency oscillation; a metal target entering the field absorbs energy by eddy currents, the oscillation collapses, and a threshold stage switches the output. No contact, no wear, immune to dirt and oil — which is why inductives are the default position sensor on machinery wherever the target can be metal.
Rated sensing distance Sn scales with coil (barrel) diameter. The catalogue's OsiSense XS general-purpose ladder:
| Barrel | Typical Sn (flush) | Example |
|---|---|---|
| Ø6.5 mm smooth | 2.5 mm | XS106B3PAM12 |
| M8 | 2.5 mm | XS108B3PAM12 |
| M12 | 4 mm | XS112B3PAM12 |
| M18 | 8 mm | XS118B3PAM12 |
| M30 | 15 mm | XS130B3PAM12 |
| 26×26 / 40×40 / 80×80 blocks | 10 / 15–20 / 40 mm | XS7E 26×26, XS7D 80×80 |
Design the mechanics for an operating distance of ~0.8 × Sn at most — mounting tolerance, temperature drift and target run-out eat the rest. Sn is defined on mild steel; correction factors reduce it on other metals (stainless roughly ×0.7, brass/aluminium ×0.4, copper ×0.3 — per-model data sheets govern).
A flush-mountable (shielded) sensor can sit with its face level in steel — robust, protected, but shorter Sn. Non-flush (unshielded) types need a metal-free zone around the face and reward you with up to double the distance. The catalogue names mounting condition per item; the "Optimum" compact series (XS508 Ø8, XS530 Ø30) are the cost-effective flush DC 2-wire line.
PNP vs NPN: a PNP output switches the load to +24 V (load to 0 V) and dominates European PLC inputs; NPN sinks to 0 V and dominates Asian-built machines. Match the input card, nothing else. NO vs NC: NO closes on target; NC is chosen where a broken wire must read as "target present" for fail-safe logic. 2-, 3- or 4-wire: 3-wire DC is standard (brown +, blue −, black signal); 2-wire types (like the Optimum DC line) wire in series with the load and leak a small off-state current — check the PLC input accepts it; AC 2-wire versions (XS218 Ø18 AC) interface legacy 230 V circuits. Connection formats: M8/M12 connector or pre-wired cable (2/5/10 m) — see the connector reference.
For targets that aren't metal — liquids, plastics, wood — step to capacitive (XT230 Ø30), ultrasonic or photoelectric sensing: the photoelectric guide maps those choices.