If you are working with automation and control systems, you must have heard about proximity sensors. These sensors are extensively used in industrial applications for detecting the presence or absence of an object. PNP 4 wire proximity sensors are one of the widely used sensors in the industry. In this article, we will discuss the wiring diagram of a PNP 4 wire proximity sensor and other related information.
What is a PNP 4 Wire Proximity Sensor?
A PNP (Positive-Negative-Positive) 4 wire proximity sensor is a type of inductive sensor that uses an alternating current (AC) at the sensing coil’s resonance frequency for detecting metallic objects. These sensors operate on 24V DC and have four wires – positive, negative, signal and shield wire. The signal wire of the sensor delivers the output signal that indicates the object’s presence or absence.
PNP 4 wire proximity sensors can detect objects at a range of a few millimeters to a few centimeters, depending on the sensor’s size and rated sensing distance. These sensors are widely used in automation and control systems like conveyor systems, packaging machines, material handling systems, and many more.
Wiring Diagram of PNP 4 Wire Proximity Sensor
To wire a PNP 4 wire proximity sensor, you need to connect the sensor’s four wires to a power supply and the input of the controller. The wiring diagram of a PNP 4 wire proximity sensor is as follows:
| Wire Color | Function |
|---|---|
| Brown | Positive (+24V DC) |
| Blue | Negative (0V DC) |
| Black | Signal (output) |
| Transparent | Shield (ground) |
Connect the brown wire of the sensor to the positive terminal of the power supply. Then connect the blue wire of the sensor to the negative terminal of the power supply. After that, connect the black wire of the sensor to the input of the controller. Finally, connect the transparent wire of the sensor to the ground terminal of the power supply.
The wiring diagram of a PNP 4 wire proximity sensor is straightforward, and anyone with basic knowledge of electrical systems can wire it easily. However, you must follow the manufacturer’s guidelines and specifications while wiring the sensor to avoid any damage or malfunctioning of the sensor.
Frequently Asked Questions
1. What is the working principle of a PNP 4 wire proximity sensor?
A PNP 4 wire proximity sensor works on the principle of inductance. When a metallic object enters the magnetic field generated by the sensor’s coil, it induces eddy currents in the object. These eddy currents create an opposing magnetic field that changes the inductance of the sensing coil. The sensor detects this change in inductance and generates an output signal that indicates the object’s presence or absence.
2. What is the difference between PNP and NPN proximity sensors?
The main difference between PNP and NPN proximity sensors is the type of output signal they generate. PNP sensors deliver a positive output signal when the object is detected, while NPN sensors deliver a negative output signal. The wiring diagram of the two sensors is also different. In a PNP sensor, the load is connected between the positive terminal of the power supply and the output of the sensor, while in an NPN sensor, the load is connected between the output of the sensor and the negative terminal of the power supply.
3. What are the factors to consider while selecting a proximity sensor?
Several factors need to be considered while selecting a proximity sensor, such as the sensing range, sensing object, operating temperature, output type, mounting type, and the environment in which the sensor will operate. You must select a sensor that meets your application’s requirements and provides accurate and reliable sensing.
4. Can PNP 4 wire proximity sensors detect non-metallic objects?
No, PNP 4 wire proximity sensors cannot detect non-metallic objects as they work on the principle of inductance and require metallic objects to induce eddy currents in them. However, there are other types of proximity sensors like capacitive and ultrasonic sensors that can detect non-metallic objects.
5. What are the applications of PNP 4 wire proximity sensors?
PNP 4 wire proximity sensors are extensively used in industrial applications like conveyor systems, packaging machines, material handling systems, CNC machines, and many more. They are used for detecting metallic objects like screws, nuts, bolts, and other metallic components.
Conclusion
A PNP 4 wire proximity sensor is a widely used proximity sensor in industrial applications. The wiring diagram of a PNP 4 wire proximity sensor is straightforward and easy to wire. In this article, we discussed the wiring diagram of a PNP 4 wire proximity sensor and other related information. We hope this article will help you understand PNP 4 wire proximity sensors better.
