Product: Inductive Proximity Switch SN04-N (3-wire, NPN, NO) Key benefits Reliable metal detection: Detects ferrous and non-ferrous metal objects up to 4 mm for consistent presence and position sensing. Clear status feedback: Built-in LED indicator shows switching state — the LED lights when a metal target is detected for the normally open (NO) configuration. Simple installation and wiring: Three-wire connection with clear assignment for positive, negative and signal output keeps setup fast and error-resistant. Wide operating range and adequate drive: Operates across a broad supply range and provides a switching output capable of driving common loads up to 300 mA. Main specifications Model: SN04-N Type: Inductive proximity switch, 3-wire, NPN, Normally Open (NO) Sensing distance: 4 mm Supply voltage: 5–30 V (DC) Output current capacity: 300 mA LED indicator: Lights when metal object detected (for NO configuration) Wiring: Connect positive supply to the positive wire/terminal, blue to negative (ground), black to the load (signal output) Function and compatibility The SN04-N is an NPN open-collector (sinking) output: when a metal target enters the 4 mm sensing range, the sensor switches and the output sinks current to ground. Ensure the load or controller input shares the same ground and does not exceed the 300 mA rating. LED provides immediate visual confirmation of detection for troubleshooting and setup. Compatible with a wide range of control systems, PLC inputs, relays, and low-voltage actuators within the specified supply and current limits. Practical use scenarios Conveyor presence detection: Detect metal parts passing a point on a conveyor for counting, sorting, or triggering downstream equipment. Position sensing in machinery: Monitor the end position of metal components on pneumatic or linear actuators to confirm travel and enable safe sequencing. Automated assembly and pick-and-place: Confirm presence or absence of metal fasteners or components before assembly steps or robotic pick operations. Installation and operation tips Maintain the sensing distance: Mount the sensor so metal targets are within the specified 4 mm detection range for reliable operation. Wiring: Connect supply + to the positive wire/terminal, blue to negative (0 V), and black to the load or controller input (signal output). Ensure common ground between sensor and control device. Observe current limits: Keep the switched load under 300 mA and within the 5–30 V supply range. Use appropriate mounting and alignment to prevent missed triggers and to maximize lifetime and stability. Safety and reliability notes Do not exceed the stated supply voltage or output current rating. Confirm wiring polarity before power-up to avoid damage. For integration with PLCs or other inputs that expect a sourcing signal, provide an appropriate pull-up or interface to accommodate the NPN sinking output. This SN04-N inductive proximity switch provides straightforward metal detection, visible status indication, and a robust output suitable for common automation and sensing tasks.