Both sensor families detect an object without touching it, but they answer different questions. An inductive proximity sensor reacts to metal only; a capacitive proximity sensor reacts to almost anything that changes the dielectric constant in front of its face – plastic, granules, liquids, glass. Picking the wrong family is the most common reason a proximity sensor “works on the bench and fails on the line”.
Side-by-side comparison
| Property | Inductive (M18, 8 mm) | Capacitive (M30, 15 mm) |
|---|---|---|
| Detects | Metals only (ferrous and non-ferrous) | Any material: plastic, liquid, grain, glass, wood |
| Typical range | 8 mm | 15 mm (sensitivity adjustable) |
| Through a container wall | No | Yes – level detection behind plastic or glass |
| Dust / moisture sensitivity | Low | Higher – face contamination can trigger it |
| Typical jobs | Metal part present / position of machine slides | Fill level, non-metal part presence, jam detection |
| Housing / connection | M18 threaded barrel, IP-rated, M12 plug | M30 threaded barrel, IP-rated, M12 plug |
Selection rules that hold up in practice
- Metal target within 8 mm? Inductive, every time – it ignores dust, chips and coolant that would false-trigger a capacitive head.
- Plastic, liquid or granular target? Capacitive, and mount it so the face can be wiped or blown clean; sensitivity is adjusted on the body.
- Wiring both types: keep the run to the M12 waterproof connector short and use a properly rated waterproof connector – most field failures traced to “bad sensors” are actually connector entries that were never sealed.
- Range derating: capacitive sensing distance drops with the dielectric constant of the target; apply the nominal 15 mm only to water-like media, and test-set the switch point on the real product.
Both models and the full range of industrial automation components are listed with dimensions and electrical data on the product pages.
FAQ
Can I use a capacitive sensor to detect metal?
Yes, but you lose the inductive sensor’s immunity to contamination, and the switch point varies with the target. If the target is metal, inductive is always the cleaner answer.
What supply voltage do the KaiVoy sensors take?
Standard DC three-wire ranges used on automated lines – the exact rating and output type (PNP/NPN) is on each product page, and we confirm it against your PLC input cards when you send an enquiry.
Do you supply with cable or with connector?
Both exist in the industry; the pages linked above show the fitted option for the KaiVoy models, and mating M12 cords are orderable with the sensor.