SN04-N Inductive Proximity Switch Sensor – NPN, Normally Open, 4 mm
Description
The SN04-N sensor is a compact inductive proximity switch designed to detect metal objects within approximately 4 mm of its sensing face. It features NPN, normally-open output, an LED indicator, and a durable ABS housing. It is commonly used in automation, robotics, CNC machines, and general non-contact detection applications.
Pin-Out & Wiring
The sensor utilises a 3-wire configuration:
| Wire Colour | Connection | Description |
|---|---|---|
| Brown | 10 – 30 V DC | Positive supply |
| Blue | 0 V (GND) | Negative supply |
| Black | Signal (NPN open-collector) | Pulls low when metal detected |
A pull-up resistor (1 kΩ–10 kΩ) is required on the signal line when connecting to microcontrollers or logic circuits.
Dimensions & Mechanical Details
Typical module size: 35 mm × 18 mm × 18 mm (L×W×H). The cable length is around 1 m, and the mounting holes fit M3 screws for easy installation.
Electrical Specifications
| Parameter | Value |
|---|---|
| Supply Voltage | DC 10 – 30 V |
| Current Consumption | ≤ 5 mA |
| Output Load Current | 200–300 mA |
| Detection Distance | 4 mm (effective range ~3.2 mm recommended) |
| Response Frequency | Up to 500 Hz |
| Protection Rating | IP65–IP67 |
| Operating Temperature | –20 °C to +70 °C |
| Housing | ABS plastic, resin-filled |
Usage & Setup
- Wire brown to positive supply, blue to ground, and black to input with pull-up resistor.
- The LED indicator illuminates when a metal target is detected.
- Ensure the sensing face is aimed directly at the target object and within the rated detection distance.
- Mount securely using M3 screws to prevent vibration or misalignment.
Troubleshooting
- No output or LED inactive: Verify wiring and supply voltage (10–30 V).
- Output always ON: Ensure no metal is near the sensor and confirm correct wiring.
- Intermittent triggering: Keep target within 3–4 mm; check for dirt, dust, or vibration.
- Driving high loads: If load exceeds 200 mA, use an external transistor or relay.
FAQs
- Can it detect non-ferrous metals?
- Yes, but detection distance is reduced compared with ferrous metals.
- Does it include a built-in indicator?
- Yes, a red LED illuminates when a target is detected.
- How fast can it switch?
- It can respond in under 2 ms, with a typical operating frequency of 500 Hz.