Inductive Proximity Sensor: Types, Application and Working Principle

In today’s world of manufacturing and industries, sensors act as imperative devices that help make processes smart and intelligent. A type of sensor that is absolutely required in a given action is the inductive proximity sensor. Common in different industries, this kind of sensor provides metallic object detection with a high level of accuracy without mechanical touch, hence useful in rough conditions. In this detailed guide about inductive proximity sensors, we shall discuss the definition, categories, functions, operation methods, cost aspects and circuit layout of this sensor.

What is Inductive Productivity Sensor?

An inductive proximity sensor can be defined as a type of sensor that utilises an electromagnetic field to detect the existence of metallic substances. These sensors are proximity types of sensors, which denote that they do not come into physical contact with metals in their attempt to sense them. These types of sensors are mostly employed in industries, such as automation systems and manufacturing lines, for object recognition, process control, and safety.

Inductive proximity sensors are a type of sensor that is not prone to wear and tear, similar to other sensors where their component is in direct contact, making them ideal for a dusty and filthy environment. These sensors are mostly cylindrical or rectangular in shape, with dimensions, range of detection and styles of use varying depending on the needs of the user.

Inductive Proximity Sensor How It Works?

To understand how inductive proximity sensors work, it is essential to delve into their core principle: electromagnetic induction. Inductive proximity sensor working principle revolves around production of a magnetic field and also sensing of the produced field. Here’s how it functions:

• Oscillator Circuit: The sensor consists of an oscillator plate circuit that will produce a high-frequency AC signal. This current is passed through a coil, and it produces an electromagnetic field ahead of the sensor.
• Detection Zone: As we know, when a metallic object enters this detection zone, it interrupts the electromagnetic field. This disturbance creates eddy currents within the metal, which in turn neutralise the energy belonging to the electromagnetic field.
• Signal Processing: The sensor is able to identify the change that has occurred in the magnetic field due to the presence of metallic objects. This change is then taken by the signal circuit to change it into a macro output, for example, an ON/OFF signal output.
• Output Signal: This output can further be applied to initiate alarms, shut down a machine, or perform any other control actions depending on the design of the sensor.

Inductive Proximity Sensor Types

Inductive proximity sensors can be of different types depending on the kind of use and the function that it will be required to perform.

• Shielded (Flush) Sensors: Coaxial shields have an annular metal band around the sensing face of the device and focus the electromagnetic field ahead of the sensor. This design is best suited for when one wants to give accurate readings with minimal influence from the neighbouring objects.
• Non-Shielded (Non-Flush) Sensors: In non-shielded sensors, the sensing face is not covered, and hence, the electromagnetic field gets higher or spread out. These sensors operate at a range that is far from that of shielded sensors, but they are prone to interference.
• Extended Range Sensors: These kinds of sensors come with complicated circuits, which gives them a longer detecting range than normal sensors. They are fit for use in cases where bigger distances from the object being sensed to the sensing surface are desired.
• Factor 1 Sensors: The first feature of Factor 1 sensors is that they assess a similar distance of any of the metals in the material. They are, however, well suited for the detection of several metals such as aluminium, copper and iron without requiring re-calibration.
• Analog Sensors: While regular Inductive sensors only provide for switching indications between ‘ON’ and ‘OFF’ positions, the Analog sensors generate variable outputs depending on the distance from the target distance, allowing for very accurate determination of the position of an object.

Application of Inductive Proximity Sensor

Proximity sensors that utilise inductive proximity technology are applied frequently in a wide variety of industries because of their high accuracy, reliability, and versatility. Some common uses include:

• Manufacturing and Assembly Lines: Inductive proximity sensors are widely employed to determine the position of metallic components, to keep track of equipment condition and to manage automation equipment.
• Robotics: These sensors are important in robotics as they give positional information about the objects and detect any metal parts to increase the precision of the robotic arms.
• Automotive Industry: Inductive proximity sensors used in automotive manufacturing include detecting metal parts during automotive manufacturing, checking whether the parts have been assembled correctly, and checking the quality of the manufactured parts.
• Packaging Machines: They are used in packaging machines to identify the presence of metal objects, including lids or caps, to ascertain that they are well placed during packaging.
• Elevator Systems: Inductive proximity sensors are employed in elevator applications to determine the door positions for the correct opening and closing of the door.
• Industrial Automation: These sensors are used in industrial automation for position sensing, speed control, and the detection of movements of various parts.

Inductive Proximity Sensor Circuit

To understand how to design an inductive proximity sensor circuit, one needs to know its basic block, which includes the oscillator block, detection coil, amplifier block, and output block. Here’s a simplified overview of the circuit design:

• Oscillator: It is clear that the oscillator produces a high-frequency signal which passes through the detection coil. The coil generates an AC electromagnetic field. An AC current flows in the primary coil, thus producing an oscillating magnetic field.
• Sensing Coil: The sensing coil is at the core of the sensor, and its role is to generate the magnetic field with which metal objects are to operate or interact.
• Amplifier and Demodulator: The amplifier helps to amplify the signal picked up from the sensing coil, while the demodulator helps in decoding the changes in the electromagnetic field.
• Output Stage: The output stage translates the signal that has been processed into a usable form for the purpose of further interfacing with control systems such as electrical ON/OFF signals.
• Power Supply: Sensors require a stable power compensation; usually, the operating voltage lasts from 10V DC to 30 V DC.

Factors Affecting Inductive Proximity Sensor Price

The following are the most important aspects affecting the Inductive Proximity Sensor Price:

• Detection Range: Devices with extra sensing ranges are widely preferred because they come with more expensive technologies necessary to boost the electromagnetic field.
• Material and Build Quality: Sensors manufactured by employing Stainless Steel and other superior quality materials are more reliable and thereby costlier.
• Environmental Protection: Normally, sensible sensors with higher IP codes, such as IP67 or IP68, are built tough and may illustrate a much higher cost.
• Special Features: Sensors that have extra features such as factor 1 detection, analogue output, or the ability to work in low temperatures or even at high temperatures may cost more because of the added function that they offer.
• Brand and Supplier: As for the factors influencing the cost of sensors, the reputation of the brand and the availability of sensors from other sources also matter. Purchasing from reputable brands guarantees that the product is reliable and that it comes with the support it comes with.

Also Read: Electrical Contactors: How they work and what are they used for?

Conclusion

Inductive proximity sensors have highly transformed how industries, especially those that deal with metallic objects, are checked as well as controlled without physically touching them. Due to their flexibility, robustness, and accuracy, these systems find their application in automation, production, and industry. This blog has provided information on what an inductive proximity sensor is, how the device works, the different types available and their uses to guide users when choosing a proximity sensor to suit a particular task.

If you are interested in using higher-quality inductive proximity sensors in your work process, it is worthwhile visiting Lauritz Knudsen Electrical and Automation Smartshop. Lauritz Knudsen offers a wide portfolio of intricate sensors with a specific focus on fulfilling the needs of the industrial world, making it your ideal partner in elevating your automation systems.