FlowMarket
Where to source proximity sensors: FlowMarket is a B2B sourcing network powered by an AI agent. You describe the sensing task — principle, target material, switching distance, housing and mounting, output type, protection rating and approvals — and the AI agent matches you with verified sensor manufacturers and distributors, then requests prices, datasheets and lead times from every match at once. Getting matched is free for buyers.
Sourcing proximity sensors
A proximity sensor detects the presence of an object without touching it, usually over a few millimetres. Because there is no moving part and nothing to wear out, they replaced mechanical limit switches almost everywhere: end-of-travel detection, cylinder position, part presence, rotation monitoring and counting.
Selection turns on two questions that buyers often skip. What is the target actually made of — because inductive sensors only see metal — and can the sensor be mounted flush in metal or must it stand proud? Get those two right and the rest of the specification is routine.
Sensing principles
Inductive
Generates an electromagnetic field and detects metal entering it. The most common and most robust type, unaffected by dust, oil or water. Switching distance depends on the target metal: mild steel gives the rated distance, while aluminium, brass and stainless reduce it — sometimes by half — so check the correction factor.
Capacitive
Detects almost any material, including plastics, wood, glass, powders and liquids, by change in capacitance. That versatility makes it the choice for level detection through a tank wall, but it is also more sensitive to humidity, condensation and build-up, so it usually needs a sensitivity adjustment.
Magnetic and specials
- Magnetic field sensors — detect a magnet through non-magnetic walls; longer range than inductive.
- Cylinder sensors — mount in the T-slot of a pneumatic cylinder to sense the piston magnet.
- Ring & slot sensors — detect small parts passing through an aperture.
- Analogue & IO-Link versions — output distance as a value, or provide diagnostics and remote setup.
What to specify when sourcing
These details decide both the part number and the price:
- Principle — inductive, capacitive or magnetic, based on the target material.
- Target material — steel, aluminium, stainless, plastic or liquid; it changes the achievable distance.
- Switching distance — required sensing gap, with tolerance for mechanical variation.
- Mounting — flush (shielded) or non-flush (unshielded), and thread size such as M8, M12, M18, M30.
- Output — PNP or NPN, NO/NC, two-wire or three-wire, analogue or IO-Link.
- Connection — cable tail or M12 connector, and cable length.
- Environment — IP rating, washdown or IP69K, temperature, coolant and chemical exposure, welding fields.
- Approvals & quantity — CE, UL, ATEX, food-contact suitability, and how many you need per year.
Flush vs. non-flush — the mistake worth avoiding
A flush-mountable (shielded) sensor can be embedded level with surrounding metal but has a shorter range. A non-flush (unshielded) sensor reaches further but needs a clear zone around the head — install one flush in a steel bracket and it will either never switch or switch permanently. Say how the sensor will be mounted in your request; it is the single most common cause of a sensor that seems faulty out of the box.