Inductive proximity sensors are suitable for many applications. By choosing a model with Factor 1 functionality, you can more easily use it to detect targets made of a variety of metals.
Almost all forms of machine and equipment automation are based on the precise detection of the presence of physical components. Proximity sensors, also known as proximity switches or proximity switches, are a great way to achieve this in many applications. Their non-contact operation makes them durable and their solid state nature makes them extremely reliable. As a result, proximity sensors can improve the overall durability and reliability of virtually any automated sensing system.
Inductive proximity sensors are specifically designed to detect ferrous metals, while capacitive proximity sensors can detect both metallic and non-metallic targets. For many reasons, sensor technology is the best choice for many machine sensing applications. The metal is very common, durable, economical and easy to use as targets on machines. Because inductive sensors by their nature cannot see other materials, they are not easily fooled by random materials, dust, water, or other environmental factors.
As with any automation component, there are factors to consider when choosing the right sensor for a specific application. This includes the required form factor, expected sensing distance, and target material. One of the disadvantages of standard non-contact sensors is the sensitivity of this model when used on various metal target materials (especially ferrous and non-ferrous metals). This results in the need to specify multiple models to meet the requirements of different applications.
A special class of inductive proximity sensors with a correction factor of 1 solves this problem by providing a constant sensing range without adjustment, regardless of the metal of the object. We’ll look at some aspects of proximity sensors and show how Factor 1 sensors can help meet automated sensing needs.
Inductive proximity sensors are compact and reliable and provide a suitable method for detecting the presence or absence of metal in automation applications. All data provided by AutomationDirect.
Limitations of Standard Inductive Proximity Sensors Inductive proximity sensors are best suited for detecting the presence of metal (Figure 1). Traditional versions of these sensors use a single ferrite core and coil to generate and measure electromagnetic fields. When a metal object enters the field and interacts with it, the switch is activated, indicating its presence.
Proximity sensors react to different metals at different distances, resulting in range depending on the material of the object. The nominal target is usually considered to be mild steel, so the correction factor in this case is 1 (or factor k = 1, sometimes abbreviated K1). Other metals containing little or no iron will result in a reduced response range, and each sensor manufacturer will provide data tables indicating the k-factor for certain materials.
For example, if the target is made of aluminum, a proximity switch can be installed that provides a sensing distance of 3 mm with a k factor of 0.5. So the effective sensing distance in this case is actually 1.5 mm.
Standard proximity sensors come in a variety of diameters and sensing distances, but each sensor must be carefully selected for its specific application.
To meet the diverse needs of end users, proximity sensors are cylindrical in shape with a diameter ranging from 3mm to 30mm. Generally speaking, the larger the diameter, the longer the sensing distance. In addition, within any size there may be standard (1X), extended (2X), triple (3X) and even some quadruple (4X) response range options (Figure 2). Therefore, there are many options, but the response range relative to the correction factor must be assessed for each location.
Other considerations may apply to all types of proximity sensors. For example, if the sensor will be installed flush or in a metal location, it must be rated for that use so that the installation does not affect its performance.
Adaptation to changing sensing distances under different conditions is not ideal. For end users with different sensing needs, this means that more device types must be specified and stocked, and different mounting clearances are required to achieve correct sensing. Factor 1 proxy sensors provide a cost-effective solution to this problem.
Factor Sensor 1: Problem Solution A suitable inductive proximity sensor will have the same range and sensitivity for any type of metal target. Apart from mild steel, common industrial materials include stainless steel, aluminum, copper, brass, etc. Ideally, the sensor can be used throughout the machine without any adjustments or special adjustments.
In fact, this is achieved through a new technology that provides proximity sensors with a k factor of 1 for all metals. Various techniques allow Factor 1 sensors to achieve greater sensitivity while increasing the ability to detect the presence of various metallic materials. The result of this technology is a constant sensitivity range for all types of target metals. This greatly simplifies the design, application, commissioning and inventory of proximity sensors.
Ratio 1 inductive proximity sensors offer many advantages over traditional technologies, making them the right choice for many new and retrofit applications, especially since they require virtually no additional cost.
The main advantage is the increased measuring range of all metals, not just steel. This means the sensor can be installed with increased clearance from moving parts, minimizing the chance of damage. Their higher sensitivity also ensures that less fine tuning is required to detect difficult metal targets.
For manufacturing applications where product conversion involves various metals that need to be detected, Factor 1 technology is the obvious choice. But even on machines and equipment that are expected to rarely need to be replaced, there may often be a need to detect targets made of different types of metals.
Because Factor 1 sensors are more adaptable, they save design effort because there is no need to choose among multiple devices for an application. This allows machine builders to find the sensors they need early in the design process and then quickly move on to the next task.
New designs benefit from Factor 1 sensors because engineers can focus on standardization to ensure consistency, which also results in fewer parts that need to be stocked. For all the above reasons, these retrofit sensors are also suitable for retrofitting, subject to confirmation of installation, sensing distance and electrical compatibility. For both new and existing applications, the best reason to use standard proximity sensors is to fit existing in-service equipment or inventory.
Regardless of which type of sensor is selected, it must be rated for the environmental conditions. Factor 1 sensors are available in stainless steel versions up to IP69K and are suitable for high pressure and high temperature washing, so there is likely to be a version suitable for most applications.
The K1 Proximity Sensor provides stable range for many metal materials, making it a good value when considering cost based on sensing distance.
Design Considerations Although the K1 sensor must detect all metals at the same distance, it is important to evaluate each application (Figure 3). The situation where the sensor is in a fixed location (and various types of metal targets pass by) is very specific and not necessarily universal across the industry. However, this feature demonstrates the product’s versatility in situations where designers use one K1 sensor model to replace several different instances on a machine or system, thereby reducing maintenance.
The biggest advantage of the K1 sensor is cost and distance estimation. For a given housing size and material type, the cost of the sensor increases as the sensing range increases. Using a typical 12mm diameter flush sensor as an example, the standard sensing range is 2mm, the extended sensing range is 4mm, the triple sensing range is 6mm and the quad sensing range is up to 8mm.
Generally speaking, as a flight doubles in size, the cost increases. If the application measures stainless steel, the corresponding correction factors will result in a 30% reduction in range. This results in spending more money on a triple sensor model, which effectively provides an extended detection range.
The K1 sensor costs about the same as the advanced sensor, but provides the same measurement range for any metal. By using K1 sensors, designers not only realize better cost, but can also reduce the number of maintenance parts and robust design installations required due to any changes in target materials.
Ruler? Inductive proximity sensors have become the mainstay of metal detection in all forms of industrial and machine automation due to their exceptional durability and reliability. However, traditional sensors are somewhat application dependent and require a lot of design effort to select the right sensor.
Factor 1 sensors use specialized sensing and receiving coils to overcome this disadvantage and are therefore capable of detecting a variety of metal targets with consistent range and sensitivity. This not only makes Factor 1 sensors more suitable for new applications, but also allows them to be retrofitted into existing systems. This flexibility reduces design costs and allows users to minimize the number of sensor parts in stock. Since all these benefits have virtually no difference in cost, choosing a single-factor inductive proximity sensor is the obvious choice in most applications.
Paul J. Heaney, vice president and editorial director of Design World magazine, holds a bachelor’s degree in engineering and mechanical engineering and a bachelor’s degree in technical communications and biomedical engineering from the Georgia Institute of Technology. For 25 years, he has written on topics in hydropower, aerospace, robotics, medicine, environmental engineering, and general manufacturing. His writing has received numerous regional and national awards from the American Society of Business Publications Editors.
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Post time: Dec-18-2023