Check if Cap is in Correct Position with Proximity Fiber

In the application video below you can see how it's possible to decide if the bottle cap is in the right position for the next production step. If not the cap will be blowing away by air. The machine builder uses a proximity fiber on top of the cap.
The bright, glossy top of the cap gives a high remission and is close to the fiber head, that leads to a long impulse of high actual value at the fiber amp. The inner white of the cap is far away from the proximity fiber head, therefore only two short impulses from the higher rim of the cap will occur. Because of the constant speed of the feeder it's easy to decide between the long impulse of the correct cap and the short impulses from the wrong positioned cap. Only a timer in the fiber amp or the customer PLC has to check "signal longer than time x = cap in wrong position > activate the air blower. Shorter impulses will be ignored.

Picture of the proximity fiber mounted on top of the cap: