need help in writing program in comparator circuit

[jeddai]

any one can help me to write program in simatic s7.
i have two rotating pulleys with with 4 pulse per turn, i want to detect and give an alarm if pay off pulley are not rotating or not giving pulse. one pulley are attached to the line speed reference and the other to the pay off bobbins.
thanks

 

[PLC wizzaahd]

Sounds like you have plenty to figure out. Good luck with this. It sounds like a really tough project.

 

[bernie_carlton]

Imagine that you are sitting in a room. All you see is a light that is sometimes on and sometimes off. The light is triggered by the pulse from the pulley. Now, what about the action of the light tells you that the pulley is rotating or not? What should the light normally be doing? How are you going to tell if something is wrong? Think about this then let it be a guide.

 

[jrwb4gbm]

To add to what bernie carlton said, here's a hint:
I would use two timers per pulley, but there's more to it than that.