need help to identify the moving mustache on the over head conveyor

any input would be appreciated!
we had one over head conveyor system, we need to identify every moving mustache position at loader and unloader to synchronize with loader carrier and unloader carrier. we use photo sensor to detect the every flag of the mustaches. what is best way to do the logic program?
thanks!

the file is too big, cant attach.

There are many ways to do what you want but I think for anybody to help you. You will need to provide a lot more information
It sounds like you want a shift register or maybe a FIFO will work

still try to draw a picture to better explanation.

still try to draw a picture to better explanation.

every carriage mustache has even space, we made a logic ladder before, but it failed, what is bother us is the two rods between every flag.it gives us identification fault at conveyor motor acceleration period when the photo sensor is at the rod spot.we use RTO instruction.
we need clear pulse from every flag, but not interrupted by those rods.

Looking at your drawing the flag is much bigger than the rod, so I would set up a timer for the prox that said don't give signal unless you are flagged longer than a rod flag time.

Or use 2 prox switches spaced far enough apart that the rod can only be on one at a time but the flag can hit both.

very very nice idea, the flag length is 11.5 inches, there is connector to connect the top chain and the rod, so exactly the rod going through photo sensor is rod connector which has length about 2.5-3 inches, prox switch is not good for this case, since the rod connector thickness is much bigger than the flag, sometimes it could get bent by accident, it is hard to detect flag very closely, we can use two photo sensors apart which distance maybe bigger than half of the flag, that is good enough to identify the flag at any situation.
thank you very much to help us!