Photo eyes should have a relay somewhere on your machine. Ryko uses Carlo Galvazzi photo eyes and relays. The relay will have 3 lights on the face and when you put something in front of the photo eye one of the lights will go n or off. The relay also has a dial on it that lets your vary the strength of the signal. I always have mine turned up to maximum. As you turn the dial down the lights will cycle on or off and give an idication of the strength of your photo eyes. The photo eyes have a transmitter and receiver. They come with either a black wire lead or a gray wire lead. In my experience the black wire photo eyes fail about 4 times as often as the gray wire. I get my photo eyes from Kaman bearing and pay about 1/3 the price I would from Ryko.
When you say that your machine is taking 45 seconds to reset after each wash it leads me to believe that one of your treadle plates is sticking or the wire connection for the mercury switch mounted on the treadle plate is getting wet and it takes that long to get dry enough to start working again.
On your PLC you should mark each light that should be lite up when the machine is operating correctly and ready to accept a wash. Then you can easily glance at the PLC lights and see what signals are missing or are extra and refer to the input and output sheet on your electrical cabinet
door to narrow your search for the problem.
I always replaced my treadle plates with pressure pads and had much better luck with the pads.