How to Choose a Photoelectric Proximity Sensor: Guide to Types of Photoelectric Sensors

In the world of modern industries, photoelectric sensors act as the “eyes” of the production line. From counting high-speed packaging to detecting the minute position of a robotic arm, these components are vital for automation.

This guide discusses the different types of photoelectric sensors to help purchasing engineers select the best type for their industry’s needs. It also presents how to avoid common pitfalls in international procurement. 

Understanding the Core Types of Photoelectric Sensors

In general, proximity sensor systems or proximity switches function as an “electric eye” that senses changes in temperatures, fluid levels, and other small details. They are mostly used in manufacturing companies with production lines and industries where safety and security are crucial. 

Compared to proximity sensors, photoelectric sensors use light (photo) to detect objects at a distance. Proximity sensors use invisible magnetic fields to “sense” objects that are close by. The best example of proximity sensors is the face-detection feature of smartphones. Choosing the right sensor depends on what you need to detect and how far away it is.

As a purchasing engineer, knowing the different types of photoelectric sensors will help you determine the most appropriate and cost-effective proximity sensor for your industry’s needs:

1. Through-Beam – also known as opposed mode, transmitted beam, direct-scanning, or break-beam. The transmitter and receiver are housed in separate units. Installation is slightly costly and complicated because they require the exact mounting of two separate components that each require a power source. 

Through-Beam sensors provide the longest range in sensing distance. They are perfect for detecting objects in motion and are reliable in dirty environments. Opaque objects can be detected regardless of their shape, material, or color. 

A through-beam photosensor detects whenever an object crosses between the transmitter and receiver, which breaks the connection and results in an alarm or triggered action.

2. Retroreflective Sensors – also known as polarized retro-reflective sensors. In this setup, the photodetector transmitter and receiver are housed in the same unit. It is also recommended for long-distance detection and can detect transparent or shiny objects. They can also detect clothing, textiles, dust, and sand. These sensors are easy to install due to simple wiring. 

Retro-reflective photosensors utilize a “reflector” to bounce light back from an object. When an object blocks the light, the sensor detects the obstruction for an amount of time and triggers an alarm or action. 

3. Diffuse-reflective Sensor or Optical Proximity Sensor – One of its best features is its space-saving component because it requires a single-unit sensor installation. This is a huge benefit in small or restrictive spaces. It also works best in detecting minuscule objects at close range. The difference between the diffuse mode sensor and the retro-reflective sensor is that the diffuse mode sensor “diffuses” the light from an object to trigger the action. 

Diffuse mode sensors are easy to install because it is a single-unit system and no reflector is required. The only downside is the complicated setup of the sensing parameters due to its close-range proximity. 

An advanced type of diffuse mode sensor is the Background Suppression Sensor. It provides an even better solution than retro-reflective or diffuse-reflective sensors. It is the ideal diffuse-sensing mode because it ignores reflective backgrounds even behind dark, less reflective objects. The caveat is that background suppression sensors are more expensive due to their complexity.

The table below presents the different proximity sensor applications:

Frequently Asked Questions

Photoelectric sensor manufacturers should offer quick solutions for common technical issues. Here are some of the frequently asked questions:

Question1: Can I use a photoelectric sensor to detect clear plastic? 

Answer: Yes, use a retro-reflective polarized sensor as this can detect transparent objects in mid-range.

Question2: The photoelectric sensor is flickering in a dusty factory – what should I do?

Answer: Increase the excess gain or switch to a through-beam photoelectric system which works best for a dusty environment.

Question3: Which do I choose – inductive, capacitative, or photoelectric?

Answer: These are different sensors for different uses. To detect metal only, choose inductive. For liquid or non-metals, use capacitive. For visual detection, photoelectric sensors are recommended.

Conclusion

Selecting the right hardware is only part of the equation. The photoelectric sensor price is only a minor factor as compared to the safety, efficiency, and security of your industry. Getting it onto your production area is the other. This is where Simply Buy Global transforms your procurement process.

We recognize that for engineers in Mexico, Peru, and across Latin America, there is a high acceptance of Chinese-made sensors due to their reliability and cost-efficiency. However, communication is often a barrier. Simply Buy bridges this gap by providing professional technical support in Spanish, ensuring your requirements are understood perfectly from the first inquiry.

Beyond technical support, we resolve the “pain points” of international shipping that slow down your projects:

• Inventory Management: The manufacturer has a ready supply of photoelectric, inductive, and capacitive sensors, ready for immediate dispatch.

• Orders to Indonesia: The company offers specialized support for self-clearance and local logistics while navigating the complexities of Indonesian import regulations.

• Orders to Russia: We offer reliable “grey clearance” solutions to ensure your supply chain remains uninterrupted despite regional logistical hurdles.