FAQs on Reflex Light Barriers

Reflex light barriers use LED red light for contactless object detection. If the light beam between the sensor and the defined background is interrupted, the sensor switches. The functional principle is based on a detection method that integrates both the energetic and the triangulation principle in one sensor.

More about the functional principle

Reflex light barriers can detect semi-transparent objects. The use of a static reference background, such as a stainless steel end piece, is recommended for the application. For particularly transparent materials, it is advisable to use retro-reflex sensors for transparent objects.

Reflex light barriers and retro-reflex sensors work with different functional principles. While reflex light barriers work with a defined background, retro-reflex sensors only work in combination with a reflector.

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To the retro-reflex sensors

PNG//smart reflex light barriers P1PM enable a range of up to 1,000 mm on a white reference background with 90% remission. The range depends, for example, on the remission level of the background and the mounting angle. Reflex light barriers P1MM detect objects up to a range of 500 mm. 

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Various factors must be considered during the installation of reflex light barriers, which vary depending on the application and reference background. These factors include, for example, the positioning and orientation of the barrier with highly reflective surfaces.

More about the installation instructions

A protective housing is available for the 1P format. Please note that there may be restrictions, e.g. with regard to the range.

To the protective housing

With PNG//smart retro-reflex sensors, two teach-in modes can be set via IO-Link. A teach-in can be set to static or moving reference background.

More about the teach-in modes

Dynamic readjustment dynamically adjusts the taught-in switching thresholds to gradual changes in the signals (e.g. in the event of slow contamination of the optics). This prevents the sensor from being taught in again.

A distinction must be made between the same remission between object and background and different remission. In the case of different remission, the hysteresis is not relevant, as the sensor detects the object based on the difference in intensity. With the same remission between object and background (example, white 90% remission), a switching hysteresis of < 5% is defined for P1PM sensors.