A magnetic reed sensor responds to a magnet rather than to metal. That gives it a decisive advantage in one common situation: sensing through a non-magnetic wall. The magnet can sit inside a sealed cylinder, tank or enclosure while the sensor stays outside, with nothing penetrating the barrier.
Reed switch technology
Inside the sensor, two ferromagnetic reeds sit inside a sealed glass capsule with a small gap between them. When a magnet approaches, the reeds magnetise, attract each other and close the contact. Remove the magnet and they spring apart. There is no contact with the target and no power drawn while idle.
The sealed capsule means the switching contacts never see the outside atmosphere — no oxidation, no dust ingress at the contact surface, and a long service life in dirty environments.
Key features
- PNP sourcing output — provides a positive signal when actuated.
- Normally open — output turns on when the magnetic field is present.
- Senses through non-magnetic walls — aluminium, stainless steel, plastic and glass.
- 30 V DC rating — compatible with standard industrial control systems.
- Available from M6.5 upward in larger diameters as needed.
- Brass and mild steel housing options for durability in harsh environments.
- No standby power draw and no physical contact with the target.
Technical specifications
| Parameter | Value |
|---|---|
| Brand | WEE |
| Sensor type | Magnetic reed switch |
| Model | PNP NO — normally open, PNP output |
| Magnetic type | Cylindrical |
| Operating voltage | Up to 30 V DC |
| Housing material | Brass (mild steel option available) |
| Available sizes | M6.5 and larger diameters |
| Frequency | 50 Hz |
| Power source | Electric (DC) |
| Actuation | Permanent magnet |
Typical applications
- Position sensing on doors, valves and linear actuators.
- Limit switching on CNC machines and robotic arms.
- Liquid level detection in tanks and pumps using a magnetic float.
- Security systems — door and window position monitoring.
- Automation control feeding PLCs, relays and counters.
How to order
Tell us the sensing gap, the target material, your supply voltage and the output type your controller needs. If you are replacing an existing sensor, a photograph of the body markings is usually enough for us to identify an equivalent. We will confirm the specification and quote — normally the same day.
Related products
Frequently asked questions
Do I need to buy the magnet separately?
Yes, unless your application already has one — for example a pneumatic cylinder with a magnetic piston, or a magnetic float in a level assembly. Tell us the sensing gap you need and we will recommend a suitable magnet.
Can a reed sensor detect ordinary steel without a magnet?
No. A reed sensor needs an actual magnetic field. To detect plain metal with no magnet, use an inductive proximity sensor instead.
Will it work through a stainless steel cylinder wall?
Through austenitic (non-magnetic) stainless such as 304 or 316, yes — that is a standard application. Through magnetic stainless grades or mild steel, no, because the wall shields the field.
Need a quote for the Cylindrical Magnetic Reed Sensor?
Send us your application — target material, sensing distance, supply voltage and housing constraint. We will recommend a part, quote it, and ship from Mumbai.