Autonics PSN40-20DN 20mm NPN Rectangular Inductive Proximity Sensor

A. Product Overview

The Autonics PSN40-20DN is an inductive proximity sensor from the PSN series. It is designed to detect metallic objects without requiring physical contact between the sensor and target.

Its rectangular body design makes it suitable for installations where cylindrical proximity sensors may not be convenient. With a sensing distance of up to 20 mm, the PSN40-20DN can detect approaching metal objects and provide an electrical switching signal to a PLC, relay, counter, controller, or other automation equipment.

Key Features

• Model: PSN40-20DN

• Product type: Inductive proximity sensor

• Body type: Rectangular

• Sensing distance: 20 mm

• Output type: NPN

• Operation: Normally open

• Power supply: 12 to 24 VDC

• Detection method: Inductive sensing

• Detectable target: Metallic objects

• Non contact detection

• Protection rating: IP67

• Suitable for industrial automation

• Suitable for PLC and machine control applications

• Designed for repetitive industrial sensing

The PSN40-20DN is particularly useful where a relatively long sensing distance is required for detecting metal components.

B. Working Principle

The Autonics PSN40-20DN operates using the inductive proximity sensing principle.

An inductive proximity sensor generates a high frequency electromagnetic field around its sensing surface.

When a metallic object enters this electromagnetic field, electrical currents called eddy currents are generated in the metal target.

These currents affect the electromagnetic field produced by the sensor.

The internal electronic circuit detects this change and switches the sensor output.

The operating sequence can be understood as follows:

1. The sensor is supplied with 12 to 24 VDC power.

2. An electromagnetic field is generated at the sensing surface.

3. When no metal object is present, the output remains in its normal condition.

4. A metallic object moves toward the sensor.

5. The metal enters the electromagnetic sensing field.

6. The sensor detects the change in the electromagnetic field.

7. The NPN output switches.

8. The output signal is sent to the connected PLC, relay, counter, or controller.

9. When the metallic object moves away, the sensor returns to its original state.

Because there is no mechanical contact with the target, the sensor can perform a very large number of detection cycles with minimal mechanical wear.

C. Why Is the Autonics PSN40-20DN Used?

The PSN40-20DN is used when machines need reliable detection of metallic objects without physical contact.

Mechanical switches need direct contact with the moving component. Continuous mechanical contact can result in wear, alignment problems, or reduced operating life.

An inductive proximity sensor avoids these issues by detecting the target electronically.

Common Uses

The PSN40-20DN can be used for:

• Metal object detection

• Machine position sensing

• Component presence detection

• Conveyor object detection

• Machine limit detection

• Gear position detection

• Metal plate detection

• Production line automation

• Assembly line monitoring

• Packaging machine automation

• Material handling equipment

• Counting metallic components

• Machine sequencing

• Automatic production equipment

• Industrial interlocking

• Position confirmation

• Parts detection

• Automation safety logic

Why Use a 20 mm Sensing Distance?

A longer sensing distance can help when the target cannot move extremely close to the sensor.

The 20 mm sensing range can be useful for applications involving:

• Larger machinery

• Moving metal components

• Conveyor installations

• Difficult mounting positions

• Applications requiring additional clearance between the target and sensor

This can make installation and alignment easier in certain industrial environments.

D. Suitable Buyers

The Autonics PSN40-20DN is suitable for companies and professionals involved in industrial automation, machinery, manufacturing, and electrical control systems.

Typical buyers include:

• Industrial automation companies

• Machine manufacturers

• Original equipment manufacturers

• System integrators

• PLC automation companies

• Control panel manufacturers

• Electrical panel builders

• Conveyor manufacturers

• Packaging machine manufacturers

• Material handling companies

• Automobile component manufacturers

• Pharmaceutical machinery manufacturers

• Food processing machinery manufacturers

• Manufacturing plants

• Assembly line manufacturers

• Industrial maintenance departments

• Factory automation companies

• Electrical engineers

• Automation engineers

• Instrumentation engineers

• Maintenance engineers

• Machine designers

• Production engineers

• Industrial spare parts buyers

Frequently Asked Questions

1. What is the Autonics PSN40-20DN?

The Autonics PSN40-20DN is a rectangular inductive proximity sensor designed for non contact detection of metallic objects in industrial automation applications.

2. What is the sensing distance of PSN40-20DN?

The PSN40-20DN provides a sensing distance of up to 20 mm.

3. What type of proximity sensor is PSN40-20DN?

It is an inductive proximity sensor.

4. What objects can the PSN40-20DN detect?

The sensor is designed for detecting metallic objects.

5. Can PSN40-20DN detect plastic?

An inductive proximity sensor is primarily designed for detecting conductive metallic targets. It is not normally selected for detecting plastic, glass, paper, or similar non metallic materials.

For those applications, a photoelectric or capacitive sensor may be more suitable.

6. What output does PSN40-20DN provide?

The PSN40-20DN uses an NPN output configuration.

7. Is PSN40-20DN normally open?

Yes. The PSN40-20DN uses a normally open switching configuration.

8. What power supply does PSN40-20DN require?

The sensor operates from a 12 to 24 VDC power supply.

9. Is PSN40-20DN a contact sensor?

No. It detects metal objects without physical contact.

10. What is an inductive proximity sensor?

An inductive proximity sensor is an electronic sensor that detects metallic objects using an electromagnetic field. When metal enters the sensing field, the sensor changes its electrical output.

11. Can PSN40-20DN be connected to a PLC?

Yes. Its NPN output can be connected to a compatible PLC digital input.

The PLC input configuration should be checked to confirm compatibility with an NPN sensor.

12. What does NPN mean in a proximity sensor?

An NPN sensor switches its output toward the negative side of the DC supply when activated. It is commonly used with PLC inputs designed for NPN sensor connections.