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U-system photo sensors


The Schlüter universal system, or U-system for short, enables the use of photo sensors in the M18 (SPM-18) and M30 (SPM-30) designs and fiber optics in a wide variety of applications. Few basic devices are supplemented by a large number of different fiber optics. Due to their robust design and the complete encapsulation with silicone, the sensors are very insensitive to vibrations, impacts and mechanical loads.

The lack of optical focusing and the associated high transmission energy make the devices insensitive to dust, steam and dirt. Still, the devices are safe for humans as they do not use laser light and invisible infrared light is not focused on the retina.

The glass fiber optics enable use in tight, inaccessible places and at temperatures of up to 300 ° C. If installed appropriately, it can be used as a light barrier in industrial ovens with an internal temperature of over 1.000 degrees. Small objects can also be detected at distances of up to 4 m.

But the devices can also be used without problems in Siberian cold.

The U-System is therefore often used wherever difficult conditions prevail and years of trouble-free operation are still necessary.

There are customers who have been using the Schlüter U-System photo sensors for decades without problems.

Features and benefits

  • Robust design, completely encapsulated
  • Sensors with high transmission power
  • Devices for fast switching operations
  • No optical focusing
  • Easy installation and handling
  • Precisely adjustable
  • Insensitive to extraneous light
  • Thousands of possible combinations with fiber optics


  • Types M18 and M30 with metal housing
  • Cable and connector versions
  • Switching frequencies up to 20.000 Hz
  • Insensitive to extraneous light
  • Glass fiber reflex sensors with ranges up to 800 mm
  • Fiber optic light barriers with ranges of up to 4.800 mm
  • Integrated PNP and NPN switching output
  • NC / NO switchable

Product catalogue

Reflex light barrier: photo sensors and light guides from Schlüter

Choose photo sensors and light guides from Schlüter, your specialist for automation and sensor technology. Here you will find products and solutions that will convince you. We advise you optimally on your individual use of linear axis systems and sensors and your satisfaction is our top priority.

Reflex light barrier: excellent products

With us you can be sure that you are buying excellent products, and we will create an optimal solution for your specific application. Within the category “Photo sensors and light barriers” you will also find the reflex light barrier under the optical sensors on our website Take a moment to take a look at the overview of the available types, the advantages and the product catalog. We would be happy to advise you on further questions.

Reflex light barrier: various dimensions and housing shapes

You can find photo sensors and light guides in various dimensions and housing shapes. Our smallest design is Ø 4 mm x 22 mm. You can get these as reflex sensors or as one-way photoelectric switches. Buy the inexpensive models, but also the other sensors for special applications. This includes the reflex sensor with background suppression.

Other types available

In addition to the reflex light barrier, you can also buy the cylindrical design in Ø 4 mm, M5, M12 and M18 or the reflex sensor with and without background suppression as well as the through-beam light barriers and the fiber optic sensors. The advantages are apparent. Discuss your purchase of the reflex light barrier or another device with our support. With us you not only get inexpensive models, but also devices with high switching speed, with large switching distances and always with a robust design. The high quality standard will convince you and our sensors are insensitive to contamination. In addition to the reflex light barrier, we offer you a wide range of standard products.

More than 50 years

We can look back on more than 50 years of experience. When purchasing your reflex light barrier or another product, have the product catalog sent to you or view it online as a PDF file.