Distance-based photoelectric sensors address more challenging applications than photoelectric sensors that only detect the absence and presence of an object. Not only do they determine the presence of something, but also its position or distance by using two different technologies.

Pepperl+Fuchs' Multipixel Technology (MPT) enables highly reliable and interference-free distance measurement for near-range applications. This technology combines the measuring functionality of conventional distance sensors with the proven triangulation principle. With this geometric method, an emitter—LED or laser—emits a light beam to the object, which reflects it back. The reflected light beam is then recaptured by a light-sensitive receiver in the sensor, the multipixel array. Depending on the position of the light spot on the receiver, the distance of the object to the sensor is calculated by geometric triangulation. This is done using intelligent software algorithms.

Pulse Ranging Technology (PRT) is a method developed by Pepperl+Fuchs that allows even large distances to be measured with high precision. This technology is based on short laser pulses emitted by a powerful light source. A light-sensitive receiver element in the sensor detects the light pulses reflected by the object. The distance to the object is calculated precisely by directly measuring the time of flight of the light. The high energy density of the laser pulses enables long ranges to be achieved and interference to be effectively suppressed.