Pepperl+fuchs Phototalk

Background suppression sensors contain an emitter and two receiver elements, a near receiver and far receiver, all in the same housing. Based on triangulation, objects in the foreground are detected when emitted light is reflected onto the near receiver and background objects are suppressed when emitted light is reflected onto the far receiver.  Because objects are detected based on which receiver the light is reflected on, black and white targets are detected at virtually the same distance.  Background evaluation sensors function just the opposite and use the background as a reference.  Objects are detected when they pass between the sensor and background and light is reflected onto the near receiver or in the case of curved surfaces, on neither receiver. --Background suppression sensors detect objects based on triangulation --Background suppression sensors detect black and white at almost the same range --Background evaluation sensors can accurately detect irregular shaped objects